Improved Flammability Standards for Thermal/Acoustic Insulation Materials Used in Transport Category Airplanes

Part III

Department of Transportation

-----------------------------------------------------------------------

Federal Aviation Administration

-----------------------------------------------------------------------

14 CFR Parts 25, 91, et al.

Improved Flammability Standards for Thermal/Acoustic Insulation

Materials Used in Transport Category Airplanes; Final Rule

Federal Register / Vol. 68, No. 147 / Thursday, July 31, 2003 / Rules

and Regulations

[[Page 45046]]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 25, 91, 121, 125, and 135

[Docket No. FAA-2000-7909; Amdt. Nos. 25-110, 91-275, 121-289, 125-43,

135-85]

RIN 2120-AG91

Improved Flammability Standards for Thermal/Acoustic Insulation

Materials Used in Transport Category Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting upgraded flammability standards for

thermal and acoustic insulation materials used in transport category

airplanes. These standards include new flammability tests and criteria

that address flame propagation and entry of an external fire into the

airplane. This action is necessary because the current standards do not

realistically address situations in which thermal or acoustic

insulation materials may contribute to the propagation of a fire. This

action is intended to enhance safety by reducing the incidence and

severity of cabin fires, particularly those in inaccessible areas where

thermal and acoustic insulation materials are installed, and providing

additional time for evacuation by delaying the entry of post-crash

fires into the cabin.

DATES: This final rule is effective on September 2, 2003.

FOR FURTHER INFORMATION CONTACT: Jeff Gardlin, FAA Airframe and Cabin

Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft

Certification Service, 1601 Lind Avenue SW., Renton, Washington 98055-

4056; telephone (425) 227-2136, facsimile (425) 227-1149, e-mail:

[email protected].

SUPPLEMENTARY INFORMATION:

Availability of Rulemaking Documents

You can get an electronic copy of this final rule using the

Internet by:

(1) Searching the Department of Transportation's electronic Docket

Management System (DMS) Web page (http://dms.dot.gov/search);

(2) Visiting the Office of Rulemaking's Web page at http://www.faa.gov/avr/arm/index.cfm; or

(3) Accessing the Federal Register's Web page at http://www.access.gpo.gov/su_docs/aces/aces140.html.

You can also get a copy by submitting a request to the Federal

Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence

Avenue SW., Washington, DC 20591, or by calling (202) 267-9680. Make

sure to identify the amendment number or docket number of this

rulemaking.

Small Business Regulatory Enforcement Fairness Act

The Small Business Regulatory Enforcement Fairness Act (SBREFA) of

1996 requires FAA to comply with small entity requests for information

or advice about compliance with statutes and regulations within its

jurisdiction. Therefore, any small entity that has a question regarding

this document may contact their local FAA official, or the person

listed under FOR FURTHER INFORMATION CONTACT. You can find out more

about SBREFA on the Internet at our site, http://www.faa.gov/avr/arm/sbrefa.htm. For more information on SBREFA, e-mail us at [email protected].

Background

On September 20, 2000, the FAA published a Notice of Proposed

Rulemaking (NPRM) in which we proposed to adopt upgraded flammability

standards for thermal and acoustic insulation materials used in

transport category airplanes. See 65 FR 56992. The NPRM included the

following:

[sbull] A test to measure the propensity of the insulation to

spread a fire; and

[sbull] A test to measure the fire penetration resistance of the

insulation.

Readers should refer to the NPRM for information about the

background of this rulemaking, including descriptions of the following:

[sbull] The types of insulation materials used in airplanes;

[sbull] Other FAA regulations relating to insulation materials;

[sbull] Past incidents involving insulation materials; and

[sbull] Fire safety research activities and findings.

The background material in the NPRM also contains the basis and

rationale for these requirements and, except where we have specifically

expanded on the background elsewhere in this preamble, supports this

final rule as if it were contained here. That is, any future

discussions regarding the intent of the requirements may refer to the

background in the NPRM as though it was in the final rule itself. It is

therefore not necessary to repeat the background in this document.

The comment period on the NPRM extended 120 days and closed on

January 18, 2001. We received comments on the NPRM from twenty-six

commenters, including aircraft manufacturers, insulation manufacturers,

aviation industry associations, a labor union, and individuals. None of

the commenters disagree with the objectives of the proposal. Ten of the

commenters expressed explicit support for the objectives of the NPRM or

for the NPRM in general. We discuss specific, substantive comments in

the ``Discussion of the Final Rule'' section later in this preamble.

Legal Basis for the Final Rule

The FAA's authorizing legislation gives the agency general

authority to take actions necessary to carry out the law, including

prescribing regulations (49 U.S.C. 40113). The FAA is responsible for

promoting safety in civil aviation and, in carrying out that

responsibility, has the authority to prescribe minimum standards for

the design, material, and construction of aircraft, among other things

(49 U.S.C. 44701).

The regulations we are adopting today are intended to enhance the

safety of civil aviation by reducing the possibility that insulation

materials used in airplanes will contribute to either the spread of

fire within airplanes or the penetration of external fire into

airplanes. This final rule requires new airplane type designs to

include insulation that passes improved flammability tests. It also

requires manufacturers of new airplanes that enter service after a

phase-in period to equip them with insulation that passes improved

flammability tests. Finally, it requires air carriers, operating under

part 121, to use insulation meeting the new flame propagation

requirements when they replace insulation.

The flammability tests we are adopting today will not eliminate all

damage to, or losses of, airplanes by fire, nor prevent all injuries or

deaths from airplanes fires. The improved tests will, however, ensure

that insulation used in airplanes will resist the propagation of fire

and thereby reduce the severity of fires or the speed with which fires

spread. They will also ensure that insulation will delay the

penetration of the airplanes by fire from outside. These effects will

give flight crews additional time to safely land or taxi, as well as

giving both passengers and crew more time to safely evacuate airplanes.

This final rule is focused on the goal of enhancing the safety of

civil aviation. The regulations adopted today have their origin in

incidents described in the NPRM where insulation that met our previous

flammability standards may have contributed to airplane fires. Since we

published the NPRM, there have been two more incidents where in-flight

[[Page 45047]]

fires occurred that involved thermal or acoustic insulation. The

flammability tests and criteria adopted today represent the outcome of

research conducted by our technical center in cooperation with

acknowledged experts in the field. We believe these tests and criteria

are the minimum necessary for future designs to provide an adequate

level of civil aviation safety.

This final rule enhances safety while at the same time considering

the impact on the aviation industry. For example, we are adopting

regulations that become effective for existing type designs after a

phase-in period. This phase-in period gives manufacturers time to plan

for changes in designs, manufacturing processes, and sources of supply.

The flammability test criteria we are adopting are reasonable, as shown

by research and development and the availability of materials that meet

the new standards. The flammability test requirements we are adopting

are flexible. Both the flame propagation test and the burnthrough test

requirements allow for the development and use of approved equivalent

tests.

We acknowledge that this final rule has cost implications for

airplane manufacturers. There are costs associated with testing,

obtaining, and installing upgraded insulation. Our analysis of the

costs and benefits of this final rule shows that the benefits (in the

form of reduced property damage, injury, and loss of life) outweigh the

costs. For more information on costs and benefits, see the ``Economic

Evaluation'' section of this preamble and the Regulatory Evaluation for

this final rule, which we have placed in the docket for this

rulemaking. Based on our analysis of the issues involved, taking into

account our responsibility for civil aviation safety, and the

administrative record for this rulemaking, including the comments we

received on the NPRM, this final rule is a proper and reasonable means

of carrying out our responsibility to enhance civil aviation safety.

Discussion of the Final Rule

This part of the preamble describes in general terms some of the

major features of the final rule. A reader who is interested in a quick

overview of the final rule may find this part useful. If you are

looking for a detailed description of the final rule, you should look

at the section-by-section analysis, which appears later in this

preamble, or the regulatory text itself, which appears at the end of

this document.

This final rule requires thermal/acoustic insulation material

installed in the fuselage of transport category airplanes to pass a

flame propagation test. The test involves exposing samples of thermal/

acoustic insulation to a radiant heat source and a propane burner flame

for 15 seconds. The tested insulation must not propagate flame more

than 2 inches away from the burner. The flame time after removal of the

burner must not exceed 3 seconds on any specimen. See final part VI of

Appendix F to Part 25 for more details.

For airplanes with a passenger capacity of 20 or greater, this

final rule also requires insulation materials installed in the lower

half of the airplane to pass a test of resistance to flame penetration.

The test involves exposing samples of thermal/acoustic insulation

blankets mounted in a test frame to a burner for four minutes. The

insulation blankets must prevent flame penetration for at least four

minutes and must limit the amount of heat that passes through the

blanket during the test. See final part VII of Appendix F to Part 25

for more details.

This final rule requires all transport category airplanes

manufactured more than two years after the effective date of this final

rule to comply with the new flame propagation test. This applies to

airplanes operating under parts 91, 121, 125, and 135. This means that

manufacturers have two years after the effective date of the final rule

to begin installing more flame resistant insulation materials in new

airplanes. This final rule requires all transport category airplanes

with a passenger capacity of 20 or greater manufactured more than four

years after the effective date of this final rule to comply with the

new test of resistance to flame penetration. This applies to airplanes

operating under part 121.

Airplanes must also comply with the new flame propagation test when

thermal/acoustic insulation materials installed in the fuselage are

replaced more than two years after the effective date of this final

rule. This requirement applies only to the materials that are replaced.

Both service history and laboratory testing demonstrate that the

current flammability requirements applicable to thermal/acoustic

insulation materials may not be providing the intended protection

against the spread of fires. Additionally, we consider that increased

protection against external fire penetrating the fuselage can be

provided by proper selection of the same material. We consider that the

new test methods described earlier will not only provide for increased

in-flight fire safety, by reducing the flammability of thermal/acoustic

insulation blankets, but will also provide increased time for

evacuation during externally fed, post-crash fires by increasing

fuselage burnthrough resistance.

Section-by-Section Analysis

Proposed Sec. Sec. 25.853(a) and 25.855(d)

Existing Sec. 25.853(a) requires that materials in airplane

compartment interiors meet the flammability test prescribed in part I

of Appendix F to Part 25. Existing Sec. 25.855(d) requires materials

used in construction of cargo or baggage compartments meet the same

test. In the NPRM, we proposed to add specific exceptions to these

provisions for ``thermal/acoustic insulation materials.'' The intent of

this proposal was to make it clear that thermal acoustic insulation was

not required to meet the requirements of Appendix F, part I, in

addition to the requirements of Appendix F, parts VI and VII. However,

as discussed below, this action might have confused the issue of

whether or not ``small parts'' required testing. We have therefore

decided not to adopt these proposed changes. As proposed in the NPRM,

we are deleting language from part I of Appendix F to Part 25 that

addresses thermal/acoustic insulation materials. This action has the

same effect as the two proposed additions would have had.

Section 25.856 Thermal/Acoustic Insulation Materials

Final Sec. 25.856(a) requires thermal/acoustic insulation material

installed in the fuselage to meet the flame propagation test

requirements of part VI of Appendix F to Part 25, or other approved

equivalent test requirements. This requirement does not apply to

``small parts,'' as defined in part I of Appendix F to Part 25.

The current flammability requirements focus almost exclusively on

materials located in occupied compartments (Sec. 25.853) and cargo

compartments (Sec. 25.855). The potential for an in-flight fire is not

limited to those specific compartments. Thermal/acoustic insulation is

installed throughout the fuselage in other areas, such as electrical/

electronic compartments or surrounding air ducts, where the potential

exists for materials to spread fire as well. The final rule accounts

for insulation installed in areas that might not otherwise be

considered within a specific compartment. Final Sec. 25.856(a) is

applicable to all transport category airplanes, regardless of size or

passenger capacity, since the consequences of an in-flight fire are not

related to these factors. We are developing advisory material to

describe test sample configurations to address

[[Page 45048]]

design details such as tapes and hook-and-loop fasteners.

One commenter recommended that we exclude ``small parts,'' as

defined in part I of Appendix F to Part 25, from the requirement that

insulation materials pass the upgraded flame propagation test. The

commenter pointed out that there is a ``small parts'' exception to the

flammability test in part I of Appendix F to Part 25.

The FAA agrees that ``small parts'' would not be practical to test

in the flame propagation test apparatus specified in part VI of

Appendix F to Part 25. In response, we have added to final Sec.

25.856(a) an exception for ``small parts'' from the requirement to pass

the upgraded flame propagation test. Under paragraph I(a)(v) of

Appendix F to Part 25, the FAA considers ``small parts'' to be things

that would not contribute significantly to a fire, including knobs,

handles, rollers, fasteners, clips, grommets, rub strips, pulleys, and

small electrical parts. In addition, ``small parts'' should not be

installed in proximity to each other. As a result of this change,

``small parts'' will continue to be governed by existing Sec. Sec.

25.853 and 25.855 and part I of Appendix F to Part 25.

One commenter suggested that, based on the language of proposed

Sec. 25.856, thermal/acoustic insulation not installed in the fuselage

might also have to pass the upgraded flame propagation test.

The FAA agrees that the proposed language could allow this

unintended interpretation. For this reason, we changed final Sec.

25.856(a) to specify that thermal/acoustic insulation installed in the

fuselage must meet the flame propagation test requirements.

A commenter stated that certain interior panels perform both

thermal and acoustic attenuation functions to some extent and might

therefore be categorized as thermal/acoustic insulation in the absence

of a more precise definition.

The FAA does not intend to require interior panels to comply with

final Sec. 25.856. These panels are subject to existing heat release

and smoke emissions requirements in parts IV and V of Appendix F to

Part 25, which are more relevant to the role of interior panels in fire

safety. This final rule is aimed at ensuring that thermal/acoustic

insulation materials, which are usually installed in inaccessible

areas, do not propagate fire. Their inaccessibility is what creates the

hazard, especially with regard to in-flight fires. Interior panels are

accessible and are clearly not exposed to the same threat. Thus, we do

not apply the final rule to them.

A commenter stated that certain interior panels often receive

acoustic damping treatments which, by virtue of their function, could

be interpreted as requiring compliance under the proposal. The

commenter recommended that these treatments be required to comply.

The FAA agrees in part. To the extent that acoustic damping

treatments applied to the inaccessible sides of interior panels could

permit fire propagation, they are required to pass the flame

propagation test. On the other hand, it is clear that the many possible

combinations of treatments and panels could result in large amounts of

testing. We intend to investigate whether compliance for such

treatments can be substantiated by tests on a generic panel, or whether

testing of the actual panel is necessary. Up to now, we have not

evaluated acoustical damping treatments in the context of the NPRM.

Based on comments, it appears that they are typically aluminum based,

so the adhesive used to bond the treatment to the panel is probably the

component of concern. We will evaluate any treatments provided for

review to develop guidance. As proposed in the NPRM, however, this

final rule requires that thermal/acoustic insulation installed in the

fuselage pass the flame propagation test. This includes material

installed on the pressure shell, ducts, floor panels, and within

equipment bays.

Final Sec. 25.856(b) requires, for airplanes with a passenger

capacity of 20 or greater, thermal/acoustic insulation materials

(including the means of fastening the materials to the fuselage)

installed in the lower half of the airplane fuselage to meet the flame

penetration resistance test requirements of part VII of appendix F of

Part 25, or other approved equivalent test requirements.

Final Sec. 25.856(b) applies only to airplanes with a passenger

capacity of 20 or greater. This effectively excludes the smaller

transport category airplanes, as well as airplanes operating in an all-

cargo mode. The primary reason for this is that airplanes with small

passenger capacities are not expected to realize a significant benefit

from enhanced burnthrough protection owing to their very rapid

evacuation capability. That is, they have a favorable exit-to-passenger

ratio. Since enhanced burnthrough protection will impose additional

cost, there must be a commensurate benefit to justify the requirement.

We do not consider that such benefits are substantial for airplanes

with low passenger capacities. We chose the 20-passenger threshold to

be consistent with other occupant safety regulations, such as those for

interior materials and cabin aisle width. The enhanced burnthrough

protection provided by this final rule will increase the evacuation

capability of airplanes with 20 or more passengers, regardless of the

exit arrangement.

Final Sec. 25.856(b) applies to insulation materials installed in

the lower half of the fuselage because that area is most susceptible to

burnthrough from an external fuel fire. Flames from an external fuel

fire typically impinge on the fuselage from below. Therefore, the lower

half of the fuselage derives the most benefit from enhanced burnthrough

protection. We chose this approach based on full-scale fire test data,

as documented in the reports referenced in the NPRM, and the potential

for an airplane to be off its landing gear. When the landing gear

collapse, an airplane can roll significantly, and the area most

susceptible to burnthrough can be correspondingly higher on the

fuselage than when the airplane is on its gear. By providing

burnthrough protection for the lower half of the fuselage (as opposed

to just the underside), the final rule takes this situation into

account.

This final rule establishes a standard for the ability of thermal/

acoustic insulation to resist penetration by an external flame, rather

than a standard for fuselage burnthrough per se. This distinction is

important, since fuselage burnthrough is a complex process, dependent

on many variables. For example, the ability of the fuselage to resist

penetration from an external fuel fire is directly related to the

thickness and material of the skin. Skin thickness varies considerably,

and essentially means that each airplane type has different burnthrough

resistance. In addition, factors internal to the airplane can also

affect penetration of an external fire into the occupied areas. For

example, differences in the air return grills can influence the time

required for an external fire to penetrate the occupied area.

Therefore, establishing a minimum standard for fuselage burnthrough

resistance and identifying possible means of compliance would be a

highly complex undertaking.

This final rule adopts a simple standard that increases the time it

takes for a fire to penetrate the airplane beyond what currently

exists, regardless of the specific capability that currently exists.

Since this increase in time can be achieved by addressing thermal/

acoustic insulation material, and this rule revises the standard for

insulation to address flame propagation anyway, it is in the public

interest to incorporate

[[Page 45049]]

criteria that enhance the overall level of safety and that can be

achieved with reasonable cost. Therefore, this rule addresses two

aspects of fire safety related to insulation material.

We intend this final rule to enhance the overall level of safety of

the airplane when insulation that meets the upgraded flammability tests

is installed. Because of the need to provide a suitable thermal and

acoustical environment inside the airplane, we consider it extremely

unlikely that insulation would be removed as a means to avoid having to

comply with this rule. In fact, we considered requiring the removal of

insulation material as an option to address flame propagation issues,

but rejected it since it would effectively diminish the burnthrough

capability that currently exists. Should removal of insulation become a

common practice, we will revisit the need for a specific fuselage

burnthrough standard.

A commenter asserted that the NPRM was ambiguous with regard to

whether materials installed in the lower half of the fuselage would

have to pass the fire penetration test. The commenter assumed that only

those materials installed near the exterior skin of the fuselage would

have to comply. Other commenters were concerned that the proposed

requirement would apply to any thermal/acoustic insulation installed in

the lower half, whether or not it would play a role in burnthrough.

The FAA's intent is that final Sec. 25.856(b) applies to all

thermal/acoustic insulation installed in the lower half of the fuselage

that contributes to delaying burnthrough. For example, insulation on

ducts in the lower half of the fuselage does not have to comply. To

clarify this point, we added to final Sec. 25.586(b) a statement that

it does not apply to thermal/acoustic insulation installations that the

FAA finds would not contribute to fire penetration resistance.

One commenter recommended that the flame penetration test not be

limited to airplanes with 20 or more passenger seats. The commenter

cited an accident involving an airplane with fewer than 20 seats, where

improved insulation might have provided a benefit.

The FAA does not agree with the commenter's assessment of the

potential role of insulation materials in the cited accident. The

accident involved a non-transport category airplane that does not meet

the other safety requirements of part 25. Thus, considering the

addition of insulation materials apart from the other requirements of

part 25 is not an accurate way to assess potential benefits. As noted

in the NPRM, we have assessed the potential benefits of requiring

insulation materials to pass the flame penetration test and have

concluded that smaller airplanes, with their greater evacuation

capability, would not realize a benefit commensurate with the costs of

compliance. Readers should note, however, that this final rule does not

preclude manufacturers from installing upgraded insulation materials on

smaller airplanes, if they so choose.

Several commenters recommended that the requirement for flame

penetration resistance be applied to insulation materials installed in

the entire fuselage, not just the lower half. One commenter stated that

upgraded insulation materials installed in the entire fuselage would

help protect airplanes from events such as lightning strikes, which

usually come from above or to the side of the airplane. These

commenters noted that the NPRM stated that providing such protection

would not result in great cost. Conversely, several other commenters

asked that the term ``lower half'' be better defined, or that the

requirement be changed to something related to the airplane design,

such as the window line, or the main deck cabin floor.

The FAA has carefully considered whether insulation materials

installed in the entire fuselage should have to pass the flame

penetration test. As discussed in the preamble to the NPRM, the main

issue is that the benefits of such a requirement would be negligible.

While a scenario can be envisaged where materials in the upper fuselage

would provide a benefit, the conditions would be extremely rare, and

were not evident in the benefit study used to develop the proposal. For

materials in the upper fuselage to be beneficial, the airplane would

have to be rolled an extreme amount (by specifying the lower half, the

requirement already accounts for significant roll), and still be

intact. While this scenario may not be far-fetched, there must also be

post-crash fire for there to be any benefit from the materials. An

accident that causes a combination of severe roll attitude, no fuselage

rupture, but with a post-crash fire, is extremely rare if even feasible

and is not considered a reasonable basis on which to base a

requirement. In addition, while the NPRM characterized the increased

costs as ``not great,'' it should be noted that they are also not

trivial. Any added weight would effectively be doubled, and the costs

of materials would also rise. Since these costs would not be balanced

by benefit, it would not be appropriate to mandate that the entire

fuselage be fitted with thermal/acoustic insulation that meets the

flame penetration requirement. Regarding threats from other in-flight

occurrences, such as lightning, the flame propagation test required by

final Sec. 25.856(a), which is applicable to all thermal/acoustic

insulation installed in the airplane, will provide added protection.

Final Sec. 235.586(b) applies to thermal/acoustic insulation

installed in the ``lower half of the airplane fuselage.'' This phrase

means the area below a horizontal line that bisects the cross section

of the fuselage, as measured with the airplane in a normal attitude on

the ground. We have looked at the accident history, as well as research

testing, and concluded that benefits will be realized with the lower

half of the fuselage protected. Using another measure, such as the

window line, or the main cabin floor, would not provide the intended

benefit, unless those locations were in the upper half of the fuselage.

We realize that thermal/acoustic insulation installations are not

typically tied to the upper or lower half of the airplane, so this

requirement will probably result in either changes to insulation

installation approaches, or use of the complying material over somewhat

more than half of the fuselage. Since new installations of insulation

materials will likely be required for compliance anyway, this is not

considered to be a significant point.

The FAA has determined that future design possibilities, such as

blended wing-body configurations, would have to be addressed

specifically, if the concept of the lower half is not appropriate.

As discussed above, final Sec. 25.856(b) applies to thermal/

acoustic insulation installed near the outer skin of the lower half of

the airplane fuselage. The intent of the rule, however, is to provide a

barrier that will delay entry of a post-crash fire into the occupied

areas of the airplane. Therefore, if an airplane were to incorporate

insulation not on the fuselage shell, but along the underside of the

floor, this insulation would be subject to the flame penetration test

of final Sec. 25.856(b). In the case where insulation is installed in

both places, an applicant may choose which insulation would be subject

to the flame penetration test. This will be discussed and illustrated

in more depth in a forthcoming Advisory Circular.

Both final 25.856(a) and 25.856(b) include a provision that allows

a manufacturer to substitute approved equivalent methods for the tests

specified in final parts VI and VII of Appendix F to Part 25. These

provisions allow for the incorporation of improvements to the test

methods as

[[Page 45050]]

they are identified, without requiring specific findings of equivalent

level of safety under 14 CFR 21.21. Experience has shown that such

improvements frequently originate with the International Aircraft Fire

Test Working Group (IAMFTWG) and are readily adopted by the industry.

The IAMFTWG consists of experts in the materials and fire testing

specialties who help refine and support the development of test methods

used in aviation, and includes representatives from the airlines,

airframe manufacturers, material suppliers, and regulatory authorities,

among others. A representative from the FAA Technical Center chairs

this group. The IAMFTWG is a technical peer group that contributes to

FAA research, but its activities are not regulatory in nature. Readers

should note that final parts VI and VII of Appendix F to Part 25

constitute the basic requirements, and that such equivalent methods

that might be developed would have to be adopted in total. It is not

acceptable to selectively adopt portions of a modified test method that

has been found to be equivalent and not all of the modified method. We

will make the determination of an acceptable equivalent method.

In proposed Sec. 25.856, we stated that these equivalent test

methods would be ``FAA-approved.'' One commenter suggested that, for

the sake of consistency with existing regulations, including Sec.

25.853, this simply read ``approved.'' The FAA agrees that the

suggested language is consistent with Sec. 25.853. We believe that

specifying ``FAA-approved'' adds no value. Therefore, we have accepted

the suggestion and changed the wording of final Sec. 25.856(a) and (b)

to allow for ``approved equivalent test requirements.'' We consider

this a non-substantive, editorial change.

Two commenters, representing the major airframe manufacturers in

the United States and Europe, urged that the FAA withdraw proposed part

VII of appendix F to Part 25 and propose instead a general requirement

for fuselage fire penetration resistance. Other commenters stated that

the FAA must address areas that currently have no insulation, or areas

where insulation might be removed. Some commenters stated that

insulation should be required as part of this rule.

The FAA disagrees with the comments. As noted in the NPRM, we

elected to propose a standard related to thermal/acoustic insulation,

since this approach is known to yield improved fire penetration

resistance. A requirement related to protection of the fuselage in

general involves many variables and would be much more complicated to

define. We recognize that removal of insulation would avoid complying

with the requirement. This possibility was discussed in the preamble,

and we noted our intent to monitor this possible course of action. We

agree that an ideal standard would simply require that the cabin be

protected from a post-crash fire of specified intensity for an

additional four minutes, and permit the manufacturer to develop his own

design approach. At present, we do not have a proposal or test standard

to address the overall resistance of the fuselage to fire penetration.

In addition, a proposal of that nature would go beyond the scope of

the NPRM, since the NPRM only addressed a material standard for

thermal/acoustic insulation. Nonetheless, it appears that industry is

considering alternatives that might address the issue more generally,

and we do not want to dismiss this possibility. A more general

requirement would also address concerns with areas that do not

currently have insulation, or where insulation is removed.

Nevertheless, we consider that there is a need to adopt a standard that

will provide added post-crash fire protection now, and will proceed

with adoption of the final rule. Based on the comments, however, we

consider it appropriate to review the industry's proposal to approach

burnthrough protection as an airplane performance requirement and, if

such a standard can be developed, consider it as an alternative means

of compliance. Therefore, we are considering assigning the Aviation

Rulemaking Advisory Committee (ARAC) the task of developing a

recommendation to the FAA for a fuselage burnthrough standard. In the

meantime, this regulation will be in effect, but will not actually

require compliance for newly manufactured airplanes until four years

after the effective date of the rule. If ARAC is successful in

developing an alternative approach, we will consider whether a change

to the regulations is appropriate or whether approval as an equivalent

level of safety under Sec. 21.21(b)(1) is sufficient. Regardless,

under the provisions of Sec. 21.21(b)(1), any applicant that wishes to

do so can propose an alternative standard and design features meeting

the objectives of the requirement at any time.

As noted in the NPRM, we have no plans to require installation of

thermal/acoustic insulation in areas that currently do not have this

insulation installed. Our intent is to take advantage of materials that

are typically installed to affect a safety improvement, and requiring

thermal/acoustic insulation to be installed in such areas would not be

consistent with this intent. In fact, this approach would be more

consistent with a general requirement for burnthrough protection, as

discussed above. Therefore, this issue will necessarily be addressed in

the proposed ARAC activity discussed above.

Part VI of Appendix F to Part 25--Flame Propagation Test

Final part VI of Appendix to Part 25 consists of a method of

evaluating the flammability and flame propagation characteristics of

thermal/acoustic insulation materials when exposed to both a radiant

heat source and a flame. The test method we are adopting today includes

specific instructions for constructing the test apparatus, calibrating

instruments, and conducting the test. It also includes the standards

the insulation must meet. The test involves exposing samples of

thermal/acoustic insulation to a radiant heat source and a propane

burner flame for 15 seconds. The tested insulation must not propagate

flame more than 2 inches away from the burner. The flame time after

removal of the burner must not exceed 3 seconds on any specimen.

This test method is based on American Society of Testing and

Materials (ASTM) test method E 648, which uses a modest ignition source

combined with exposure to radiant heat to determine fire propagation

performance. This test method represents a realistic fire threat and

imposes realistic success criteria, considering the state of the art of

insulation materials. The test method we are adopting today is

substantially the same as the one included in the NPRM, with the

exception of the burn-length and after-flame standards. We discuss the

changes to the standards below in the responses to comments. We have

also made minor editorial changes to the language of the test method

for clarity. These editorial changes are not substantive.

One commenter questioned the rationale for applying the flame

propagation test to all forms of thermal/acoustic insulation, rather

than just a thin film-encapsulated batting type of thermal/acoustic

insulation.

The FAA's intent is to address thermal/acoustic insulation in

general because of its location and quantity in inaccessible areas of

the fuselage. The flame propagation test represents a realistic in-

flight fire threat, and a method of assessing the tendency for

materials to spread fire. We recognize that there may be different

material/

[[Page 45051]]

installation schemes for which the flame propagation test is not well

suited. However, up to now, all currently used and prospective

materials that we have tested have been accommodated by the flame

propagation test, with no obvious incompatibilities. If an applicant

identifies an instance where this is not the case, the applicant is

free to propose an alternative method of compliance that shows

equivalent level of safety. However, based on the experience gathered

to date, this would not seem necessary.

Several commenters addressed specific details of the test

apparatus, or the test method itself, that are intended to simplify and

improve the reliability of the tests. These range from correcting

conversion of measurement units to test sample size to the type of

radiant panel used.

The FAA has reviewed the commenters suggested improvements and

adopted several of the suggested changes as appropriate; those that are

not adopted verbatim are addressed in principle. Since publication of

the NPRM, the FAA Technical Center has been working to improve the test

methods for determining the flammability and flame propagation

characteristics of thermal/acoustic insulation materials. We have

revised the test methods in Appendix VI to include these improvements.

A copy of the Technical Center's report, which includes a summary of

the improvements, is included in the public docket for this rulemaking.

We received several comments on proposed paragraph VI(h)(1), which

would have allowed no flaming beyond two inches to the left of the

centerline of the point of pilot flame application to the specimen

tested. One commenter noted that the designation ``to the left'' was

not clear, and should specify a frame of reference. Other commenters

noted that the two-inch limit was not specified as an average, or a

not-to-exceed value for a sample. One commenter proposed that it must

be an average to be viable. This commenter noted that virtually any

material will eventually exhibit a burn length greater than two inches

if enough samples are tested.

The FAA does not agree that the flame propagation length should be

adjusted. The intent of the proposal (and this final rule) is to

require materials that will not propagate a fire. The requirement that

the flame not propagate more than two inches along the sample is

intended to account for the damage that occurs as a result of the pilot

burner, but not to allow any additional flame propagation. We have

conducted hundreds of tests since issuance of the NPRM, and

determination of propagation distance has not been a problem. The

requirement of this rule is not the same as the traditional Bunsen

burner requirements for ``burn length.'' For a burn-length

determination, no distinction is made between burning caused by the

burner itself and self-sustained combustion of the material. The Bunsen

burner is oriented in the same (vertical) direction as the burn length

determination, and making a distinction would be difficult at best.

For this rule, the issue is propagation of a flame beyond the

damage caused by the pilot burner. The pilot burner is oriented at a

right angle to the direction of measured flame propagation, making the

distinction much clearer. A two-inch limit will adequately account for

the damage caused by the burner, and materials that exceed this limit

exhibit some tendency to propagate flame. Determination of the extent

of propagation requires that a person actually watch the test, however.

An after-the-fact determination is not reliable, and would probably

result in failure determinations of materials that were, in fact,

acceptable. Based on all of the data gathered to date, we are satisfied

that the criteria are readily achievable, and that samples that exceed

two inches indicate the need for corrective action. Therefore, we are

adopting the burn-length standard as proposed.

We received several comments on proposed paragraph VI(h)(2), which

would have allowed one of three specimens tested to have an after

flame, which could not have exceeded three seconds in duration. One

commenter believed that no sample should be permitted to flame after

removal of the pilot burner. Several other commenters stated that the

presence of such an ``after flame'' is highly dependent on the ability

of the person conducting the test to remove the pilot flame at

precisely 15 seconds, and that slight variation can influence whether

there is a short after flame. Several commenters recommended an average

after flame for three samples. Some suggested a maximum total after

flame time for all samples, with a maximum for any one sample. One

commenter stated that an average must be allowed, since a single sample

can effectively prohibit a material from use, regardless of how many

other samples are tested with satisfactory results.

The FAA agrees that we should adjust the pass/fail standard. We

also believe we can adjust the standard without affecting the intent of

the requirement, which is to prevent insulation materials from

spreading a fire. Based on the comments and a review of the test data

acquired to date, we agree that materials that meet the intent of the

requirement can sometimes fail the test, as proposed. (The proposed

test standard would have required two of the three test samples to have

no after flame whatsoever). As noted by commenters, this could be due

to operator variations in detailed test procedures, material

variability, or a combination of the two. While we have made every

effort to remove operator variables from the test method, the

stringency of the requirement tends to magnify whatever slight

variations exist. Similarly, slight material variations are inevitable,

even with the best materials. In light of the above, we have determined

that we should adjust the pass/fail standard for after-flame time to

account for slight variations. Therefore, we have revised final

paragraph VI(h)(2) of appendix F to Part 25 to permit after flame on

any sample, but require that none of the three samples have an after

flame time of greater than three seconds. This change allows small

variability in all of the samples, but retains the intent of the

requirement that the material not continue to burn after the pilot

flame is removed.

Several commenters addressed the fact that insulation materials

frequently consist of more than a film-covered batting material. These

commenters point out that tapes and hook-and-loop fastening systems are

often used on insulation to perform various functions. Some commenters

state that these additional features must be included in the

requirement, while others only question how they would be tested if

they were to be included.

Final part VI of Appendix F to Part 25 applies to the thermal/

acoustic insulation assembly, which includes tapes or hook-and-loop

fasteners that are affixed to the film. In addition, research testing

has shown that these details can have a pronounced effect on the flame

propagation characteristics of the insulation. We are developing

advisory material that will explain an acceptable test sample

configuration to address those details. We recognize that the use of

tapes, for example, is quite variable, and it may not be possible to

address each production configuration with a single test sample

configuration. We hope to be able to establish a critical case that may

be used to qualify other configurations, and plan to outline this

approach in the advisory material.

One commenter noted that, for air ducts in particular, the test

criteria do not provide sufficient detail as to how they should be

tested. The commenter contends that we did not give adequate

[[Page 45052]]

consideration to ducting when the proposal was developed, since

insulation on air ducts is frequently different than that attached to

the fuselage.

The FAA agrees that insulation on air ducts has not been addressed

to the same extent as other insulation. However, the concerns with fire

propagation are the same, and insulation on air ducts should meet the

same standard, as noted in the NPRM. We are developing advisory

material that will include discussion of insulation on air ducts, and

the proper method of configuring test samples. This might require

modification to some of the installation practices that are currently

employed. For example, complete surface bonding of film to the batting

material requires a large amount of adhesive, and adhesives have been

shown to be problematic for flame propagation. However, other methods

are available that will comply.

The commenter also noted that acoustic treatments are sometimes

applied to the interior of ducts, and that this treatment should not be

required to comply since it is not exposed.

The FAA agrees that this requirement would not apply to acoustic

treatment completely enclosed by ducts. However, we are studying all

materials in inaccessible areas, and intend to develop standards for

such materials that are consistent with the threat level established to

develop the flame propagation test. In that case, it is likely that the

duct construction itself would be included.

Under the current requirements, parts too large to be considered

``small parts'' require testing, and the basic requirements for the

test sample construction will be no different under this final rule.

The major difference is the size of the test sample. Parts that are

smaller than the test sample size could be addressed on a case-by-case

basis. We have reduced the sample size from that in proposed paragraph

VI(c)(2), based on data acquired since publication. See final paragraph

VI(C)(3). We encourage use of materials and constructions that meet the

radiant panel test for all such parts, no matter how small.

Part VII of Appendix F to Part 25--Flame Penetration Test

Final part VII of Appendix to Part 25 consists of a method for

evaluating the burnthrough resistance characteristics of aircraft

thermal/acoustic insulation materials when exposed to a high-intensity

open flame. The test method we are adopting today includes specific

instructions for constructing the test apparatus, calibrating

instruments, and conducting the test. It also includes the standards

the insulation must meet. The test involves use of a kerosene burner

apparatus that realistically simulates the thermal characteristics of a

post-crash fire. The test stand and specimen are configured to simulate

a small section of fuselage frame and stringers with insulation

material mounted over them. Fuselage skin is not represented in this

test since the delay in burnthrough afforded by the skin is not

directly related to the performance of the insulation. The test is

intended to measure the performance of the insulation installation

itself. The test involves exposing samples of thermal/acoustic

insulation blankets mounted in a test frame to a burner for four

minutes. The insulation blankets must prevent flame penetration for at

least four minutes and must limit the amount of heat that passes

through the blanket during the test.

For new designs, the new burnthrough test method is applicable to

the insulation as installed on the airplane. Thus, consistent with

similar flammability testing of other installed materials, the means

intended to be used for fastening the insulation to the fuselage must

be accounted for when performing tests. For consistency, the test

method imposes a standard methodology for fastening. In addition, we

are developing advisory material concerning the installation of

insulation that would enable the installer to avoid a specific test on

the fasteners, etc. Although failures of fasteners or seams during this

test may not exacerbate flame propagation characteristics, such

failures could adversely affect the burnthrough protection capability.

Since research has shown practical fastening means are available for

ensuring that the insulation material remains in place, we have

determined that fastening means must be considered for newly

manufactured airplanes.

The test method we are adopting today is substantially the same as

the one included in the NPRM. We discuss changes to the test method

below in the responses to comments. We have also made minor editorial

changes to the language of the test method for clarity. These editorial

changes are not substantive.

Some commenters asserted the test method has not been demonstrated

to be repeatable.

The FAA has sponsored three round-robin test series to date and has

made refinements to the test method and apparatus as a result. One

significant problem with the test equipment that has been rectified is

the use of various shapes and sizes of airflow vanes (stators) inside

the burner draft tube. For reasons unknown, this inconsistency in

fabrication developed and significantly contributed to the scatter of

data obtained during inter-laboratory comparisons. Since all

laboratories now have the identical stators installed, the inter-

laboratory test correlation should be much better. All test results are

currently displayed on the IAMFTWG Web site at http://www.fire.tc.faa.gov. The repeatability of results has improved with

each successive round robin, and we are satisfied that the test is

sufficiently repeatable for use in the final rule.

One commenter specifically addressed the effects of altitude as not

being accounted for in the test method, and proposes that this variable

among test facilities must be addressed.

Regarding the potential effects due to altitude of the test

facility, the FAA agrees that this is possible. In fact, the test

results seen in the round robin tests discussed above strongly suggest

that the effects of altitude are responsible for much of the variation.

It should be noted that the fuel and airflow prescribed in this test

method are meant to reflect an actual pool fire condition in which the

fuel/air ratio is typically not stoichiometric. The conditions are

representative of a large pool fire with respect to the two main

criteria of temperature and heat flux. Therefore, the differences in

combustion using the specified airflow and fuel flow values at

different altitudes would also not be expected to result in a

stoichiometric process. We agree that an altitude correction factor

could be implemented in order to obtain more repeatable test results

from labs located at various altitudes. An applicant would be free to

propose an alternative method, with supporting data. If requested, we

will work with an applicant to establish the proper correction.

Several commenters addressed specific details of the test method

and test apparatus. One commenter stated that the calibration

parameters are too narrowly specified to permit reliable calibration.

The commenter proposed tolerances on the fuel flow and air intake. One

commenter advised that the combined heat flux/thermocouple calibration

rig is not practical and separate rigs should be used. Another

commenter requested clarification of the term ``assembly processes''

for sample fabrication.

The FAA has considered detailed comments on the test apparatus

itself, and these have been adopted for the most part. The new

apparatus details are specified in final part VII of Appendix

[[Page 45053]]

F to Part 25, and do not change the scope or intent of the test. As

noted above, a significant clarification is the use of a standard

stator vane assembly for the burner draft tube.

With respect to the calibration requirements, the test method

prescribes the use of a highly dynamic fire source, the characteristics

of which are highly transient. Testing has shown that the set-up

(configuration) of the test burner plays a major role in the

performance of many materials. The parameters with which to control the

burner flame, (namely fuel flow rate, air intake velocity, as well as

the positioning of the components necessary for firing the fuel/air mix

(stators and igniter set)) must be very tightly controlled in order to

minimize error between testing facilities. A tolerance of +/-1 gallon

per hour fuel flow rate is well beyond the limit that is necessary to

eliminate fluctuation between testing facilities. Similarly, a

tolerance of +/-100 ft/min air velocity is excessive, and will only

result in increased fluctuation of test results between testing

facilities.

The accuracy of the heat flux measurement of the burner flame is

highly dependent on the condition of the heat flux transducer, its

position, and its accuracy. However, we agree that a minimum heat flux

value (rather than a range, as proposed) is sufficient to establish

whether a material performs acceptably, and have revised the test

method accordingly.

The term ``assembly processes'' is intended to address the way in

which the thermal/acoustic insulation components are built up. For

example, for a traditional batting encapsulated in a moisture barrier,

there may be seams that are heat sealed, or stitched, or utilize a hook

and loop type closure. These must be included in the test sample.

However, features added to the surface of the thermal/acoustic

insulation would not need to be included in the test sample if they do

not affect the fire penetration resistance. For example, use of tapes

on the moisture barrier will not require assessment in the fire

penetration test. Note that these same features will require assessment

in the flame propagation test of part VI of Appendix F to Part 25.

Some commenters proposed that the burnthrough time be increased to

five or six minutes to provide a margin for the desired four minutes,

or to account for more fire resistant materials. Other commenters

questioned the heat flux value specified, and proposed that it be

reduced.

The FAA does not agree that the burnthrough time should be extended

to five or six minutes. In the benefit study conducted on behalf of the

FAA by Cherry & Associates,\1\ a four-minute extension in evacuation

time is shown to provide a measurable improvement in survivability.

Beyond four minutes, there is little benefit. Although a product may

provide more than four minutes of burnthrough protection, this does not

justify a requirement if no additional benefit is provided.

---------------------------------------------------------------------------

\1\ FAA Office of Aviation Research, U.S. Dept. of

Transportation, Fuselage Burnthrough Protection for Increased

Postcrash Occupant Survivability: Safety Benefit Analysis Based on

Past Accidents, DOT/FAA/AR-99/57, Sept. 1999. Available at http://www.tc.faa.gov/its/worldpac/techrpt/ar99-57.pdf.

---------------------------------------------------------------------------

Regarding comments that the time should be extended to provide a

margin of safety that will ensure four minutes of protection, we agree

that a certification requirement cannot assure that every material lot

and batch will perform identically. However, this would be true

regardless of the time specified in the regulation. We consider that

the rule should not account for variation in material lot or batch. The

certification requirement is intended to address the basic material and

installation scheme in accordance with the type design. The

manufacturer will need to develop quality control procedures to ensure

consistent performance of the material.

The heat flux measurement provision is included in the pass/fail

criteria to account for materials that behave similarly to a flame

arrestor, and do not inhibit heat transfer. The heat flux measurement

provides an indication of the hazard inside the airplane, but

supplements, rather than replaces, the basic requirement to resist

flame penetration. Flame penetration time is the fundamental concern.

This can be described as the time at which the test burner flames

directly cause a breach to form in the insulation material, thereby

allowing the flames to pass through from the front to the back face.

For some materials, the failure event is catastrophic and the

occurrence can be measured quite accurately. However, it can be

difficult to measure the event for other longer-lasting materials, as

the failure does not occur instantaneously, but rather gradually over

time. These materials typically allow a very small breach to occur

initially, and the breach gradually increases in size as the test

progresses. As a guideline, a material can be considered to fail when

the size of the breach reaches 0.25 inch in diameter.

There have been instances where tested insulation materials

(insulation and film) have ignited on the back face and caused surface

propagation to occur. This surface propagation is not considered a

burnthrough and would be acceptable, provided the heat flux level

measured behind the sample does not exceed 2.0 Btu/ft\2\ sec at any

time during the test. However, since the same materials will also be

required to meet the flame propagation standard of part VI of Appendix

F to Part 25, it is likely that a material exhibiting this type of back

face ignition would be screened out by that test.

There have been other instances whereby flames can reach the back

side of the insulation materials by passing through passageways created

between blankets or between the sample and the test frame. This

typically occurs between clamping locations, and is generally not a

function of the material's flame penetration resistance, but rather a

result of improper mounting. This occurrence should not be considered a

failure, provided the material is not breached when inspected after the

test. We will address issues related to material overlap and

installation in a forthcoming Advisory Circular.

Several commenters addressed the issue of attachment of thermal/

acoustic insulation to the fuselage. Some commenters noted what they

consider to be a conflict between proposed Sec. 25.856 and proposed

part VII of Appendix F to Part 25, since the regulation requires that

the means of attachment comply, but the appendix specifies an

attachment scheme for test. Several commenters state that advisory

material is needed to establish acceptable means of attachment, and

stress its importance in providing burnthrough protection.

The FAA does not agree that the wording of proposed Sec. 25.856

and part VII of Appendix F to Part 25 are in conflict. As noted in the

NPRM, the test fixture is intended to test the material system in a

manner that will ensure its retention since, for the sake of

simplicity, the fixture does not replicate any specific airplane. In

other words, the installation must meet the requirement, but, for

simplicity, the test method does not include installation details. We

have participated in a research program with the Civil Aviation

Authority (CAA) in the United Kingdom to assess acceptable installation

methods. Acceptable methods can only be established using

representative airframe structure, since the interaction between the

attachment and the airframe will influence the performance of an

otherwise acceptable material. In addition to the collaborative effort

with the CAA, we have conducted additional full-scale fire tests to

assess

[[Page 45054]]

the sensitivity of burnthrough performance to minor installation

variations. As a result of this research, we are developing an advisory

circular that describes acceptable methods of installation. The

advisory circular addresses attachment schemes, overlap between the

insulation and airframe structure and overlap of more than one

insulation blanket. We recognize that other methods of installation may

be equally acceptable, or necessary, particularly with insulation

systems that are different from those described in the AC. However, an

applicant would need to demonstrate that alternative approaches provide

an equivalent level of safety. Such demonstrations would require

testing of a scale appropriate to the feature being investigated.

One commenter disagrees with discussing detailed installation

methods in an advisory circular. The commenter states that installation

methods should be part of the rule, and not separated into an AC.

The FAA does not agree. The installation methods are, in fact, part

of the regulation. However, in order to address the installation

methods in the certification test method, the test fixture would have

to be modified for each installation, which is impractical and could

lead to a lack of standardization. In addition, it is doubtful that the

scale of the oil burner test could adequately assess certain

installation issues that would be significant in a post crash fire. For

these reasons, we have elected to simplify the test method, and provide

guidance on acceptable installation methods. An applicant is free to

propose testing that would substantiate the actual installation, but we

do not intend to require this when the advisory material covers the

installation methodology.

One commenter states that the test method does not adequately

address ``non-conforming'' materials, such as rigid foams, and could

result in the placement of a fire barrier that is closer to the

calorimeter than is the case for traditional blanket materials. The

commenter contends that the relationship of the barrier to the

calorimeter can affect the test results.

The FAA agrees that the relative position of the fire barrier and

the calorimeter can influence the test results. However, we do not

agree that moving the barrier closer to the calorimeter will always

have negative effects. The relationship of the burner to the

calorimeter is constant, so the relative performance of the barrier

material, whatever it is, is based on the effect of the burner at the

calorimeter location. To vary this relationship would compromise the

standardization of the test method. We recognize that the test method

is only representative of, and not identical to, the actual fire

threat. Therefore, an applicant would be free to demonstrate that a

particular design approach provides the same level of safety if the

applicant believes that the test setup does not adequately evaluate the

design.

Operating Requirements in Parts 91, 121, 125, and 135

Newly Manufactured Airplanes

This final rule requires transport category airplanes operating

under parts 91, 121, 125, and 135 to comply with the new standards

relative to flame propagation in final Sec. 25.856(a). This portion of

the final rule applies to airplanes manufactured more than two years

after the effective date of this final rule. These requirements are

found in final Sec. Sec. 91.613(b)(2), 121.312(e)(2), 125.113(c)(2),

and 135.170(c)(2). We are adopting these requirements exactly as

proposed in the NPRM except for adding the words ``in the fuselage'' to

make clear that only thermal/acoustic insulation materials installed in

the fuselage are subject to the requirements.

Since there are materials currently available that will meet the

new standards, these requirements impose minimal additional costs.

These requirements are applicable to airplanes manufactured more than

two years after the effective date of the final rule. Two years is

considered sufficient time to allow for material production capacity to

be developed and for disposition of existing inventory.

Readers should note that these requirements differ from previous

rulemaking related to flammability of materials in that the

applicability to newly manufactured airplanes is not limited to

operations under part 121. The reasons for this are that the rule adds

minimal cost and the potential for an in-flight fire is not limited to

air carrier operations.

In accordance with Sec. 21.17, these new standards are applicable

to new type certificates for which application is made after the

effective date of the final rule. In addition to changing the design

standards for future type certificate applications, we consider that

the benefits from improved flammability standards can be realized for

existing designs as well. The technology exists today so that these

benefits can be obtained in a cost-effective manner by applying the

standards under some circumstances to newly manufactured airplanes and

to existing airplanes when insulating materials are replaced. Our means

for obtaining benefits earlier than would be provided by changing

design standards is to revise the operating rules. Requirements for

newly manufactured airplanes become a basic airworthiness requirement

for those airplanes and apply throughout their service life.

Requirements for the existing fleet relate to materials that are

replaced in service. This latter aspect of the rule does not affect

newly manufactured airplanes, since they are already required to comply

by virtue of their date of manufacture.

Replacement of Existing Insulation

This final rule requires that thermal/acoustic insulation

materials, when installed as replacements more than two years after the

effective date of this final rule, meet the new flame propagation test

requirements of final Sec. 25.856(a). This requirement applies to

existing transport category airplanes operating under parts 91, 121,

125, and 135 and to the same types of airplanes manufactured within two

years of the effective date of this final rule. See final Sec. Sec.

91.613(b)(1), 121.312(e)(1), 125.113(c)(1), and 135.170(c)(1). We are

adopting these requirements exactly as proposed in the NPRM except for

adding the words ``in the fuselage'' to make clear that only thermal/

acoustic insulation materials installed in the fuselage are subject to

the requirements.

This action provides for the gradual attrition of materials

installed under earlier standards. Since there are existing materials

that meet the new standards, and since those materials cost and weigh

only marginally more than other materials, this should result in

negligible additional cost to operators.

As with newly manufactured airplanes, it is appropriate to address

not only those airplanes operated in part 121 air carrier service, but

other operations as well, since the flame propagation portion of this

final rule enhances safety over the current regulatory requirements,

and can be done inexpensively.

Although it is difficult to quantify the benefits of piecemeal

replacement of materials, the cost of replacement is low and adds

minimal burden. This final rule allows time for attrition of current

inventories and acquisition of new materials. Replacement insulation

does not have to comply until two years after the effective date of

this final rule. We expect this requirement to have little impact since

only a relatively small amount of insulation materials are replaced

every year.

[[Page 45055]]

Larger Airplanes Operating Under Part 121

This final rule requires newly manufactured airplanes with a

passenger capacity of 20 or greater operating under part 121 to comply

with the burnthrough protection standards in final Sec. 25.856(b). See

final Sec. 121.312(e)(3). This requirement applies to airplanes

manufactured more than four years after the effective date of the final

rule. Although there are materials currently available that will meet

the standards, these materials are not widely used. Therefore, we

expect the burnthrough portion of the rule to require both material

and, in many cases, design changes. As discussed in the context of the

part 25 changes, these design changes relate primarily to the means of

fastening the insulation to the fuselage structure. For those airplanes

that require design changes, we recognize that adequate time is

necessary to perform the necessary engineering and to obtain approval

for the changes. We consider four years to be a reasonable time to

implement any design changes and configuration control measures

required to account for the new standard and to allow for material

availability.

Generally, airplanes operated under parts 91, 125, and 135 carry

fewer passengers than airplanes operating under part 121 and can, as a

result, be evacuated more quickly. Therefore, we consider that the

additional evacuation time provided by enhanced fuselage burnthrough

protection would not provide the same increase in safety for these

airplanes. In light of the costs associated with requiring compliance

with the burnthrough standard, imposing the requirement would have a

negligible benefit. This conclusion is similar to the conclusion,

discussed in the context of the proposed part 25 burnthrough standard,

not to impose the new standard for airplanes with fewer than 20

passengers. However, since transport category airplanes can be operated

under different regulatory requirements throughout their service life,

it is likely that most, if not all, affected newly manufactured

transport category airplanes will comply, to account for potential

future part 121 operations.

Replacement

This final rule does not require installation of materials

complying with the burnthrough test standards in all transport category

airplanes because it would not provide a substantial benefit. If the

fuselage is subjected to an external fire, it is unlikely that

insulation complying with this standard that has been installed in a

portion of the fuselage would significantly delay burnthrough if the

rest of the fuselage contains insulation that does not comply with the

new standard. As discussed previously, in order to be effective against

burnthrough, new insulation materials would also have to be installed

in a manner that would allow them to remain in place when exposed to an

external fire. Requiring that the means of fastening, and the

associated engineering necessary to incorporate design changes, be

accounted for on a material replacement basis would be very expensive,

with negligible benefit.

Date of Manufacture

For the purposes of this final rule, we consider the date of

manufacture to be the date on which inspection records show that an

airplane is in a condition for safe flight. This is not necessarily the

date on which the airplane is in conformity with the approved type

design, or the date on which a certificate of airworthiness is issued,

since some items not relevant to safe flight, such as passenger seats,

may not be installed at that time. It could be earlier, but would be no

later, than the date on which the first flight of the airplane occurs.

This definition has been used in previous rulemaking, including the

preamble to our February 2, 1995, final rule entitled Improved

Flammability Standards for Materials Used in the Interiors of Transport

Category Airplane Cabins (60 FR 6616, 6617).

Compliance Time

Commenters were divided as to whether more or less time should be

allowed for compliance by newly manufactured airplanes with the flame

propagation requirement of final Sec. 25.856(a). No commenter provided

any data to support this position, although one commenter noted that it

might be required to make part number changes in order to facilitate a

material changeover, which will take time. Another commenter noted that

a longer compliance period for retrofit of non-compliant insulation on

air ducts on a particular airplane type was permitted in accordance

with an airworthiness directive, and this seems inconsistent with the

proposal.

With respect to comments that the compliance period for newly

manufactured airplanes should be adjusted either up or down, in the

absence of any data to support either position, the FAA cannot justify

a change. While we agree that part number changes might be necessary,

it is not the only method to assure configuration control. Any other

method in which configuration control is assured would be acceptable.

Therefore, a change to the compliance time is not justified on this

basis.

Finally, the comment that the proposed compliance time does not

coincide with a similar airworthiness directive is not relevant to this

rule. The airworthiness directive requires retrofit of airplanes that

are already in service. This is a much more labor intensive and

complicated process than incorporating a different material in

production. Therefore no change is made to the compliance time for

flame propagation.

Paperwork Reduction Act

In accordance with the Paperwork Reduction Act of 1995 (44 U.S.C

3507(d)), we have determined that there are no requirements for

information collection associated with this final rule.

International Compatibility

In keeping with U.S. obligations under the Convention on

International Civil Aviation, it is FAA policy to comply with

International Civil Aviation Organization (ICAO) Standards and

Recommended Practices to the maximum extent practicable. We have

determined that there are no ICAO Standards and Recommended Practices

that correspond to these regulations.

Economic Evaluation, Regulatory Flexibility Determination, Trade Impact

Assessment, and Unfunded Mandates Assessment

Changes to Federal regulations must undergo several economic

analyses. First, Executive Order 12866 directs each Federal agency

proposing or adopting a regulation to first make a reasoned

determination that the benefits of the intended regulation justify its

costs. Second, the Regulatory Flexibility Act of 1980 requires agencies

to analyze the economic impact of regulatory changes on small entities.

Third, the Trade Agreements Act prohibits agencies from setting

standards that create unnecessary obstacles to the foreign commerce of

the United States. In developing U.S. standards, this act requires

agencies to consider international standards, and use them where

appropriate as the basis of U.S. standards. Fourth, the Unfunded

Mandates Reform Act of 1995 requires agencies to prepare a written

assessment of the costs and benefits and other effects of proposed and

final rules. An assessment must be prepared only for rules that impose

a Federal mandate on State, local, or tribal governments, or on

[[Page 45056]]

the private sector, likely to result in a total expenditure of $100

million or more in any one year (adjusted for inflation).

In conducting these analyses, the FAA has determined that this rule

has benefits that justify its costs. This rulemaking does not impose

costs sufficient to be considered ``significant'' under the economic

standards for significance under Executive Order 12866. Due to public

interest, however, it is considered significant under the Executive

Order and DOT policy. This rule will not have a significant impact on a

substantial number of small entities. This rule has no affect on trade-

sensitive activity. This rule does not impose an unfunded mandate on

state, local, or tribal governments, or on the private sector. The FAA

has placed these analyses in the docket and summarized them below.

Benefits and Costs

Benefits

This rule will generate safety benefits by averting accidents that

involve propagation of flame on the film bags that encase thermal

acoustic insulation batting, and by mitigating accidents that involve

fire burning through from outside an airplane into its cabin. Over a

20-year analysis period the rule is expected to avert one catastrophic

accident and a recoverable accident. The estimated present value of the

combined flame propagation and burnthrough benefits is about $222.6

million in constant 2001 dollars.

Flame Propagation Benefits

When an in-flight fire that propagates on insulation in an

inaccessible area is detected soon enough, diversion of the flight is

likely, thus averting death, injury, and damage to the airplane.

However, if such a fire is not detected until it grows beyond the

capacity of the aircrew to control, a catastrophic accident with 100

percent fatalities and the complete loss of the airplane can result.

The estimate of the expected benefits of complying with the flame

propagation requirements is based on averting such a catastrophic

accident. The components of this estimate include (1) averting the

deaths; (2) averting the loss of the airplane; and (3) averting the

costs of investigating the accident.

An example of a potential future averted accident (basis accident)

is the catastrophic accident that occurred on September 2, 1998, when

Swissair Flight 111 crashed off the coast of Nova Scotia, Canada, with

the loss of 229 lives. Although the Transportation Safety Board of

Canada has not released its final investigative report, on August 28,

2001, that agency issued Aviation Safety Recommendations, stating that

``* * *The most significant material flammability deficiency discovered

has been the inappropriate flammability characteristics of the MPET-

covered thermal acoustic insulation blankets* * *''

In September 2001, the Fire Safety Section of the FAA's William J.

Hughes Technical Center provided its professional engineering opinion

that ``* * *this rule change will likely prevent one catastrophic in-

flight accident over a twenty-year period after implementation.''

The Section supports its judgment as follows:

``During the study period from 1967 through 1998 three fatal in-

flight fires occurred on 121 carriers in North America and an

additional six throughout the rest of the world in which the fire

was in an inaccessible area and the thermal/acoustic film may have

played an important role. A review of recent incident, accident, and

service difficulty reports indicates that there are between three

and five in-flight fires causing serious damage on part 121 aircraft

in the U.S. per year. Most of those occurrences included the spread

of fire on the thermal/acoustic film. Preliminary information

obtained on one accident (Air Tran Airways, DC-9-32 on November 29,

2000, at Atlanta, Georgia) indicates that had the fire started a

little later in the flight the aircraft would not have been able to

make it back to the airport.

Given the above, it is estimated that one catastrophic in-flight

fire accident will occur every ten years in the U.S. Thermal

acoustic insulation film makes up a large percentage of the surface

area in the inaccessible areas of airplanes. If this rule change

were fully implemented, it would eliminate 50% of the annual 3 to 5

in-flight fires, thus halving the likelihood of a catastrophic

accident to one in every 20 years.'' (emphasis added)

The expected present-value benefits from averting a catastrophic

accident are estimated to include: averting fatalities ($110 million);

averting the loss of an airplane hull ($16 million); and averting the

costs of an accident investigation ($1 million). These benefits total

to $127 million.

Burnthrough Benefits

The estimated burnthrough benefits of this rule are based in the

September 1999 report ``Fuselage Burnthrough Protection for Increased

Postcrash Occupant Survivability: Safety Benefit Analysis Based on Past

Accidents,'' DOT/FAA/AR-99/57 (http://www.tc.faa.gov/its/act141/reportpage.html), hereafter referred to as the Cherry Study. This study

concludes that four minutes of additional resistance to burnthrough

will result in averting 10.1 fatalities and 13.5 injuries per year over

the worldwide fleet of passenger-carrying airplanes. The FAA adjusted

these fatalities and injuries so as to apply only to part 25 airplanes

in part 121 service over the forecast period. The present value total

benefit of $95 million includes $50 million from averted fatalities,

$34 million from averted injuries, and $11 million from averted

accident investigations

Benefit Summary

Thus, over the 20-year period of analysis examined in this

evaluation, the estimated total present value of flame propagation and

burnthrough benefits is $222.6 million.

Summary of Benefits

--------------------------------------------------------------------------------------------------------------------------------------------------------

Monetary benefits

Monetary benefits Monetary benefits derived by averting loss of derived by Total monetary

derived by aircraft or injuries averting accident benefits

averting deaths investigations

--------------------------------------------------------------------------------------------------------------------------------------------------------

Flame Propagation........................... $110.3 loss of aircraft--$15.6.......................... $1.4 $127.3

Burnthrough................................. 50.5 Injuries--33.9................................... 10.8 * 95.3

--------------------

Total................................... 160.8 49.5............................................. 12.2 * 222.6

--------------------------------------------------------------------------------------------------------------------------------------------------------

* Rounded

[[Page 45057]]

Estimates of Costs

This evaluation examines four components of cost: (1) The

acquisition of test apparatus used to establish the new testing

standards; (2) the installation and the maintenance of insulating

material to meet the flame propagation requirement; (3) the

installation of insulating material to meet the burnthrough

requirement; and (4) engineering costs, including those of

configuration management, which includes changing (also called

``rolling'') parts numbers.

Final rule evaluation estimates differ from those of the NPRM

evaluation with respect to cost components (1), (2) and (4), as follow:

[sbull] The cost of test apparatus was excluded;

[sbull] Costs of material to be installed and replaced for the

flame propagation requirement were added;

[sbull] The cost of a fuel-weight penalty for burnthrough

compliance was added;

[sbull] The engineering cost of possible changes in design and

installation of insulation blankets was eliminated;

[sbull] Costs of the engineering work of configuration management

were greatly increased.

Each of the four components of the cost estimate is considered in

turn below.

The cost of test apparatus was excluded because this cost of

compliant insulation is expected to include the cost of test apparatus.

To include the cost of test apparatus will result in counting the cost

of test apparatus twice.

This final rule evaluation found that flame propagation material

requirements is expected to add cost and weight that was not considered

in the NPRM evaluation. While neither installation during manufacture

nor replacement during maintenance is expected to add to labor costs,

each will add to cost of material and to weight. The incremental cost

of the insulation is $2.05 per square yard. The additional weight will

result in additional fuel cost.

Unlike the NPRM this final rule evaluation assigns a minimal cost

to the design and installation expense. This change in approach results

from FAA technical opinions that became available after the completion

of the NPRM evaluation. FAA technical opinions state that the common

method of installation shown will meet burnthrough requirements if a

layer of ceramic paper is laminated inside the outboard layer (the

layer next to the aluminum skin of the airplane) of the metalized

polyvinylfloride film. As the method of installation will not change,

there will be no additional engineering expense for design and

installation.

While one commenter stated that the FAA's NPRM estimate of

engineering costs was greatly overstated, this final rule evaluation

finds that the NPRM estimate of the costs of the engineering work of

configuration management costs was low. Considering other comments and

clarifications about the formalization, technical and regulatory

requirements, and organizational complexity involved in managing

aviation parts nomenclature, the FAA revised its NPRM cost estimate

upward.

The agency accepts the industry estimate that as much as eight

hours can be required to fully effect changes in nomenclature for each

aviation part involved in compliance. These eight hours make up the

time needed for work that begins with the initiation of a change in (or

with the introduction of new) nomenclature, and that ends with the

completion of the authorized and documented release of that

nomenclature to all appropriate holders.

Summary of Cost

Flame propagation present-value compliance costs are estimated to

be approximately $76.2 million. The burnthrough present-value

compliance costs are expected to be approximately $32.2 million. Thus

the total cost for this rule is $108.4 million (total does not add due

to rounding). The specific cost elements for flame propagation and

burnthough are present in the Summary of Costs table.

Summary of Costs

----------------------------------------------------------------------------------------------------------------

Maintenance

New driven Added fuel Engineering

installation replacement weight cost costs Total costs

material cost cost

----------------------------------------------------------------------------------------------------------------

Flame Propagation............... $13.8 $2.8 $1.5 $58.1 $76.2

Burnthrough..................... 20.6 .............. 2.0 9.6 32.2

-----------------

Total....................... .............. .............. .............. .............. 108.4

----------------------------------------------------------------------------------------------------------------

Comparison of Benefits and Costs

When discounted at 7 per cent annually, the present value of the

overall benefits of this final rule is about $222.6 million in constant

2001 dollars. Estimated overall costs are about $108.4 million in 2001

dollars. Thus, taken as a whole, the rule is cost effective. The

discounted present values of the benefits of the flame propagation

requirements are about $127.3 million, and comparable costs are about

$76.2 million. The discounted present values of benefits of the

burnthrough requirements are about $95.3 million, and comparable costs

are about $32.2 million. Thus, each part of the rule, considered

separately, is cost effective.

Regulatory Flexibility Determination

The Regulatory Flexibility Act of 1980 (RFA) establishes ``as a

principle of regulatory issuance that agencies shall endeavor,

consistent with the objective of the rule and of applicable statutes,

to fit regulatory and informational requirements to the scale of the

business, organizations, and governmental jurisdictions subject to

regulation.'' To achieve that principle, the Act requires agencies to

solicit and consider flexible regulatory proposals and to explain the

rationale for their actions. The Act covers a wide-range of small

entities, including small businesses, not-for-profit organizations and

small governmental jurisdictions.

Agencies must perform a review to determine whether a proposed or

final rule will have a significant economic impact on a substantial

number of small entities. If the determination is that it will, the

agency must prepare a regulatory flexibility analysis as described in

the Act.

However, if an agency determines that a proposed or final rule is

not expected to have a significant economic impact on a substantial

number of small entities, section 605(b) of the 1980 act provides that

the head of the agency may so certify and a regulatory flexibility

analysis is not required. The certification must include a statement

providing the factual basis for this determination, and the reasoning

should be clear.

[[Page 45058]]

The FAA conducted the required review of this final rule, and finds

the following:

(1) Engineering and manufacturing costs of this rule apply to

manufacturers of part 25 airplanes. No such manufacturer is a small

business;

(2) In December 2000, the FAA identified 28 airlines that were

small businesses. This evaluation assumes each will replace about 2.8%

of the insulation in each of its airplanes with rule compliant

insulation yearly, on a maintenance-driven basis. Fleet sizes of those

27 carriers still in business range from 2 to 24. The FAA believes the

average annual cost of compliance for these carriers will approximate

$60 per airplane. Based on fleet size, the annual costs incurred by

average small business carrier is estimated at $420. This amount is

less than an hour of annual operating cost for the airplanes affected

by this rule;

(3) Because the FAA believes that manufacturers will pass along

their increased compliance costs to the airlines the agency reviewed

the scope and significance of these costs to operators. The discounted

present (2001) value of the average airplane newly delivered in 2006

(the first year both flame propagation and burnthrough requirements

will be implemented) is about $34.8 million in constant 2001 dollars.

Assuming the manufacturer spreads engineering costs (for each

requirement) over a 10-year production run, about $12,000 will be added

to the cost of the average airplane. Material costs for both

requirements will add another $11,000. Thus, about $23,000, or just

under seven one-hundredths of one percent is added to the cost of the

average airplane that might be acquired by the average small business

airline. The FAA believes a small business airline that will acquire,

or will secure the use of a $34.8 million capital asset will not be

burdened by this small increment.

Accordingly, pursuant to the Regulatory Flexibility Act, 5 U.S.C.

605(b), the Federal Aviation Administration certifies that this rule

will not have a significant economic impact on a substantial number of

small entities.

International Trade Impact Assessment

The Trade Agreement Act of 1979 prohibits Federal agencies from

engaging in any standards or related activities that create unnecessary

obstacles to the foreign commerce of the United States. Legitimate

domestic objectives, such as safety, are not considered unnecessary

obstacles. The statute also requires consideration of international

standards and where appropriate, that they be the basis for U.S.

standards.

In accordance with the above statute, the FAA has assessed the

potential effect of this final rule and has determined that it will

impose the same costs on domestic and international manufacturing

entities, and will impose minimal operating costs on domestic

operators. The agency believes this final rule will approximate a

neutral impact on trade.

Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act of 1995 (the Act),

enacted as Pub. L. 104-4 on March 22, 1995, requires each Federal

agency, to the extent permitted by law, to prepare a written assessment

of the effects of any Federal mandate in a proposed or final agency

rule that may result in the expenditure by State, local, and tribal

governments, in the aggregate, or by the private sector, of $100

million or more (adjusted annually for inflation) in any one year.

Section 204(a) of the Act, 2 U.S.C. 1534(a), requires the Federal

agency to develop an effective process to permit timely input by

elected officers (or their designees) of State, local, and tribal

governments on a proposed ``significant intergovernmental mandate.''

A ``significant intergovernmental mandate'' under the Act is any

provision in a Federal agency regulation that would impose an

enforceable duty upon State, local, and tribal governments, in the

aggregate, of $100 million (adjusted annually for inflation) in any one

year. Section 203 of the Act, 2 U.S.C. 1533, which supplements section

204(a), provides that before establishing any regulatory requirements

that might significantly or uniquely affect small governments, the

agency shall have developed a plan that, among other things, provides

for notice to potentially affected small governments, if any, and for a

meaningful and timely opportunity to provide input in the development

of regulatory proposals.

This rule does not contain any significant Federal

intergovernmental or private sector mandate. Therefore, the analytical

requirements of Title II of the Unfunded Mandates Reform Act of 1995 do

not apply.

In estimating the costs associated with this final rule, we refined

the analysis that we prepared for the September 20, 2000 NPRM. See 65

FR 56998. At that time, we estimated the total discounted costs of the

NPRM to be $68.2 million. As stated above, we estimate the total

discounted cost of the final rule to be $108.4 million. The primary

reason for the increase in the cost estimate is that we believe that

the NPRM cost estimate of configuration management was too low. Based

on comments we received on the NPRM about the complexity of managing

aviation parts nomenclature, we revised the cost estimate upward.

Several commenters on our estimates of the costs of the proposed

rule address our use of a particular commercial product in the cost and

benefit assessment. Some commenters note that the material discussed is

actually a family of materials, rather than a single product, and it

could be misleading to imply that only one material is being

considered. Other commenters object to the use of any trade name, and

state that this implies that the FAA is endorsing a particular product.

As discussed in the NPRM, the FAA specifically requested

information on materials that manufacturers would use to comply with

the requirement. This was because we could not obtain definitive

information on the optimal means of compliance, and were forced to rely

on information available to make an assessment of the costs of

compliance. In so doing, we used as an example a product where the

performance and cost information could be readily obtained. This is not

a product endorsement, or even a suggestion of a preferred means of

compliance. It is merely an example that could be quantified to

illustrate what the cost of compliance could be. In order for this

information to be of any value, the particular product has to be

mentioned. Otherwise, there would be no way for the public to comment

on the validity of our estimates.

Executive Order 13132, Federalism

The FAA has analyzed this final rule under the principles and

criteria of Executive Order 13132, Federalism. We have determined that

this action will not have a substantial direct effect on the States, on

the relationship between the national Government and the States, or on

the distribution of power and responsibilities among the various levels

of government. Therefore, we determined that this final rule does not

have federalism implications.

Environmental Analysis

FAA Order 1050.1D defines FAA actions that may be categorically

excluded from preparation of a National Environmental Policy Act (NEPA)

environmental impact statement. In accordance with FAA Order 1050.1D,

appendix 4, paragraph 4(j), this rulemaking action qualifies for a

categorical exclusion.

[[Page 45059]]

Energy Impact

The energy impact of this final rule has been assessed in

accordance with the Energy Policy and Conservation Act (EPCA) and

Public Law 94-163, as amended (42 U.S.C. 6362) and FAA Order 1053.1. It

has been determined that the final rule is not a major regulatory

action under the provisions of the EPCA.

Regulations Affecting Intrastate Aviation in Alaska

Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat.

3213) requires the Administrator, when modifying regulations in Title

14 of the CFR in a manner affecting intrastate aviation in Alaska, to

consider the extent to which Alaska is not served by transportation

modes other than aviation, and to establish such regulatory

distinctions as he or she considers appropriate. Because this final

rule applies to the certification of future designs of transport

category airplanes and their subsequent operation, it could affect

intrastate aviation in Alaska. Because no comments were received

regarding this regulation affecting intrastate aviation in Alaska, we

will apply the rule in the same way that it is being applied

nationally.

List of Subjects

14 CFR Part 25

Aircraft, Aviation safety, Reporting and recordkeeping

requirements.

14 CFR Part 91

Aircraft, Aviation safety, Reporting and recordkeeping

requirements.

14 CFR Part 121

Aircraft, Aviation safety, Reporting and recordkeeping

requirements, Safety, Transportation

14 CFR Part 125

Aircraft, Aviation safety, Reporting and recordkeeping

requirements.

14 CFR Part 135

Aircraft, Aviation safety, Reporting and recordkeeping

requirements.

The Amendment

0

In consideration of the foregoing, the Federal Aviation Administration

amends parts 25, 91, 121, 125, and 135 of Title 14, Code of Federal

Regulations as follows:

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

0

1. The authority citation for part 25 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701-44702, and 44704.

0

2. Add Sec. 25.856 to read as follows:

Sec. 25.856 Thermal/Acoustic insulation materials.

(a) Thermal/acoustic insulation material installed in the fuselage

must meet the flame propagation test requirements of part VI of

Appendix F to this part, or other approved equivalent test

requirements. This requirement does not apply to ``small parts,'' as

defined in part I of Appendix F of this part.

(b) For airplanes with a passenger capacity of 20 or greater,

thermal/acoustic insulation materials (including the means of fastening

the materials to the fuselage) installed in the lower half of the

airplane fuselage must meet the flame penetration resistance test

requirements of part VII of Appendix F to this part, or other approved

equivalent test requirements. This requirement does not apply to

thermal/acoustic insulation installations that the FAA finds would not

contribute to fire penetration resistance.

0

3. Amend appendix F to part 25 as follows:

0

a. In part I, paragraph (a)(1)(ii), by removing the words ``thermal and

acoustical insulation and insulation covering'' and ``insulation

blankets'' from the first sentence.

0

b. In part I, by removing and reserving paragraph (a)(2)(i).

0

c. By adding parts VI and VII to read as follows:

Appendix F to Part 25--[Amended]

* * * * *

Part VI--Test Method To Determine the Flammability and Flame

Propagation Characteristics of Thermal/Acoustic Insulation

Materials

Use this test method to evaluate the flammability and flame

propagation characteristics of thermal/acoustic insulation when

exposed to both a radiant heat source and a flame.

(a) Definitions.

``Flame propagation'' means the furthest distance of the

propagation of visible flame towards the far end of the test

specimen, measured from the midpoint of the ignition source flame.

Measure this distance after initially applying the ignition source

and before all flame on the test specimen is extinguished. The

measurement is not a determination of burn length made after the

test.

``Radiant heat source'' means an electric or air propane panel.

``Thermal/acoustic insulation'' means a material or system of

materials used to provide thermal and/or acoustic protection.

Examples include fiberglass or other batting material encapsulated

by a film covering and foams.

``Zero point'' means the point of application of the pilot

burner to the test specimen.

(b) Test apparatus.

[[Page 45060]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.003

(1) Radiant panel test chamber. Conduct tests in a radiant panel

test chamber (see figure 1 above). Place the test chamber under an

exhaust hood to facilitate clearing the chamber of smoke after each

test. The radiant panel test chamber must be an enclosure 55 inches

(1397 mm) long by 19.5 (495 mm) deep by 28 (710 mm) to 30 inches

(maximum) (762 mm) above the test specimen. Insulate the sides,

ends, and top with a fibrous ceramic insulation, such as Kaowool

MTM board. On the front side, provide a 52 by 12-inch

(1321 by 305 mm) draft-free, high-temperature, glass window for

viewing the sample during testing. Place a door below the window to

provide access to the movable specimen platform holder. The bottom

of the test chamber must be a sliding steel platform that has

provision for securing the test specimen holder in a fixed and level

position. The chamber must have an internal chimney with exterior

dimensions of 5.1 inches (129 mm) wide, by 16.2 inches (411 mm) deep

by 13 inches (330 mm) high at the opposite end of the chamber from

the radiant energy source. The interior dimensions must be 4.5

inches (114 mm) wide by 15.6 inches (395 mm) deep. The chimney must

extend to the top of the chamber (see figure 2).

[[Page 45061]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.004

(2) Radiant heat source. Mount the radiant heat energy source in

a cast iron frame or equivalent. An electric panel must have six, 3-

inch wide emitter strips. The emitter strips must be perpendicular

to the length of the panel. The panel must have a radiation surface

of 12\7/8\ by 18\1/2\ inches (327 by 470 mm). The panel must be

capable of operating at temperatures up to 1300[deg]F (704[deg]C).

An air propane panel must be made of a porous refractory material

and have a radiation surface of 12 by 18 inches (305 by 457 mm). The

panel must be capable of operating at temperatures up to 1,500[deg]F

(816[deg]C). See figures 3a and 3b.

[[Page 45062]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.005

[[Page 45063]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.006

/(i) Electric radiant panel. The radiant panel must be 3-phase

and operate at 208 volts. A single-phase, 240 volt panel is also

acceptable. Use a solid-state power controller and microprocessor-

based controller to set the electric panel operating parameters.

(ii) Gas radiant panel. Use propane (liquid petroleum gas--2.1

UN 1075) for the radiant panel fuel. The panel fuel system must

consist of a venturi-type aspirator for mixing gas and air at

approximately atmospheric pressure. Provide suitable instrumentation

for monitoring and controlling the flow of fuel and air to the

panel. Include an air flow gauge, an air flow regulator, and a gas

pressure gauge.

(iii) Radiant panel placement. Mount the panel in the chamber at

30[deg] to the horizontal specimen plane, and 7\1/2\ inches above

the zero point of the specimen.

(3) Specimen holding system.

(i) The sliding platform serves as the housing for test specimen

placement. Brackets may be attached (via wing nuts) to the top lip

of the platform in order to accommodate various thicknesses of test

specimens. Place the test specimens on a sheet of Kaowool

MTM board or 1260 Standard Board (manufactured by Thermal

Ceramics and available in Europe), or equivalent, either resting on

the bottom lip of the sliding platform or on the base of the

brackets. It may be necessary to use multiple sheets of material

based on the thickness of the test specimen (to meet the sample

height requirement). Typically, these non-combustible sheets of

material are available in \1/4\ inch (6 mm) thicknesses. See figure

4. A sliding platform that is deeper than the 2-inch (50.8mm)

platform shown in figure 4 is also acceptable as long as the sample

height requirement is met.

[[Page 45064]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.007

(ii) Attach a \1/2\ inch (13 mm) piece of Kaowool MTM

board or other high temperature material measuring 41\1/2\ by 8\1/4\

inches (1054 by 210 mm) to the back of the platform. This board

serves as a heat retainer and protects the test specimen from

excessive preheating. The height of this board must not impede the

sliding platform movement (in and out of the test chamber). If the

platform has been fabricated such that the back side of the platform

is high enough to prevent excess preheating of the specimen when the

sliding platform is out, a retainer board is not necessary.

(iii) Place the test specimen horizontally on the non-

combustible board(s). Place a steel retaining/securing frame

fabricated of mild steel, having a thickness of \1/8\ inch (3.2 mm)

and overall dimensions of 23 by 13\1/8\ inches (584 by 333 mm) with

a specimen opening of 19 by 10\3/4\ inches (483 by 273 mm) over the

test specimen. The front, back, and right portions of the top flange

of the frame must rest on the top of the sliding platform, and the

bottom flanges must pinch all 4 sides of the test specimen. The

right bottom flange must be flush with the sliding platform. See

figure 5.

[[Page 45065]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.008

(4) Pilot Burner. The pilot burner used to ignite the specimen

must be a BernzomaticTM commercial propane venturi torch

with an axially symmetric burner tip and a propane supply tube with

an orifice diameter of 0.006 inches (0.15 mm). The length of the

burner tube must be 2\7/8\ inches (71 mm). The propane flow must be

adjusted via gas pressure through an in-line regulator to produce a

blue inner cone length of \3/4\ inch (19 mm). A \3/4\ inch (19 mm)

guide (such as a thin strip of metal) may be soldered to the top of

the burner to aid in setting the flame height. The overall flame

length must be approximately 5 inches long (127 mm). Provide a way

to move the burner out of the ignition position so that the flame is

horizontal and at least 2 inches (50 mm) above the specimen plane.

See figure 6.

[[Page 45066]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.009

(5) Thermocouples. Install a 24 American Wire Gauge (AWG) Type K

(Chromel-Alumel) thermocouple in the test chamber for temperature

monitoring. Insert it into the chamber through a small hole drilled

through the back of the chamber. Place the thermocouple so that it

extends 11 inches (279 mm) out from the back of the chamber wall,

11\1/2\ inches (292 mm) from the right side of the chamber wall, and

is 2 inches (51 mm) below the radiant panel. The use of other

thermocouples is optional.

(6) Calorimeter. The calorimeter must be a one-inch cylindrical

water-cooled, total heat flux density, foil type Gardon Gage that

has a range of 0 to 5 BTU/ft\2\-second (0 to 5.7 Watts/cm\2\).

(7) Calorimeter calibration specification and procedure.

(i) Calorimeter specification.

(A) Foil diameter must be 0.25 +/-0.005 inches (6.35 +/-0.13

mm).

(B) Foil thickness must be 0.0005 +/-0.0001 inches (0.013 +/-

;0.0025 mm).

(C) Foil material must be thermocouple grade Constantan.

(D) Temperature measurement must be a Copper Constantan

thermocouple.

(E) The copper center wire diameter must be 0.0005 inches (0.013

mm).

(F) The entire face of the calorimeter must be lightly coated

with ``Black Velvet'' paint having an emissivity of 96 or greater.

(ii) Calorimeter calibration.

(A) The calibration method must be by comparison to a like

standardized transducer.

(B) The standardized transducer must meet the specifications

given in paragraph VI(b)(6) of this appendix.

(C) Calibrate the standard transducer against a primary standard

traceable to the National Institute of Standards and Technology

(NIST).

(D) The method of transfer must be a heated graphite plate.

(E) The graphite plate must be electrically heated, have a clear

surface area on each side of the plate of at least 2 by 2 inches (51

by 51 mm), and be \1/8\ inch +/-\1/16\ inch thick (3.2 +/-1.6 mm).

(F) Center the 2 transducers on opposite sides of the plates at

equal distances from the plate.

(G) The distance of the calorimeter to the plate must be no less

than 0.0625 inches (1.6 mm), nor greater than 0.375 inches (9.5 mm).

(H) The range used in calibration must be at least 0-3.5 BTUs/

ft\2\ second (0-3.9 Watts/cm\2\) and no greater than 0-5.7 BTUs/

ft\2\ second (0-6.4 Watts/cm\2\).

(I) The recording device used must record the 2 transducers

simultaneously or at least within \1/10\ of each other.

(8) Calorimeter fixture. With the sliding platform pulled out of

the chamber, install the calorimeter holding frame and place a sheet

of non-combustible material in the bottom of the sliding platform

adjacent to the holding frame. This will prevent heat losses during

calibration. The frame must be 13\1/8\ inches (333 mm) deep (front

to back) by 8 inches (203 mm) wide and must rest on the top of the

sliding platform. It must be fabricated of \1/8\ inch (3.2 mm) flat

stock steel and have an opening that accommodates a \1/2\ inch (12.7

mm) thick piece of refractory board, which is level with the top of

the sliding platform. The board must have three 1-inch (25.4 mm)

diameter holes drilled through the board for calorimeter insertion.

The distance to the radiant panel surface from the centerline of the

first hole (``zero'' position) must be 7\1/2\ +/-\1/8\ inches (191

+/-3 mm). The distance between the centerline of the first hole to

the centerline of the second hole must be 2 inches (51 mm). It must

also be the same distance from the centerline of the second hole to

the centerline of the third hole. See figure 7. A calorimeter

holding frame that differs in construction is acceptable as long as

the height from the centerline of the first hole to the radiant

panel and the distance between holes is the same as described in

this paragraph.

[[Page 45067]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.010

(9) Instrumentation. Provide a calibrated recording device with

an appropriate range or a computerized data acquisition system to

measure and record the outputs of the calorimeter and the

thermocouple. The data acquisition system must be capable of

recording the calorimeter output every second during calibration.

(10) Timing device. Provide a stopwatch or other device,

accurate to +/-1 second/hour, to measure the time of application of

the pilot burner flame.

(c) Test specimens.

(1) Specimen preparation. Prepare and test a minimum of three

test specimens. If an oriented film cover material is used, prepare

and test both the warp and fill directions.

(2) Construction. Test specimens must include all materials used

in construction of the insulation (including batting, film, scrim,

tape etc.). Cut a piece of core material such as foam or fiberglass,

and cut a piece of film cover material (if used) large enough to

cover the core material. Heat sealing is the preferred method of

preparing fiberglass samples, since they can be made without

compressing the fiberglass (``box sample''). Cover materials that

are not heat sealable may be stapled, sewn, or taped as long as the

cover material is over-cut enough to be drawn down the sides without

compressing the core material. The fastening means should be as

continuous as possible along the length of the seams. The specimen

thickness must be of the same thickness as installed in the

airplane.

(3) Specimen Dimensions. To facilitate proper placement of

specimens in the sliding platform housing, cut non-rigid core

materials, such as fiberglass, 12\1/2\ inches (318mm) wide by 23

inches (584mm) long. Cut rigid materials, such as foam, 11\1/2\ +/-

\1/4\ inches (292 mm +/-6mm) wide by 23 inches (584mm) long in order

to fit properly in the sliding platform housing and provide a flat,

exposed surface equal to the opening in the housing.

(d) Specimen conditioning. Condition the test specimens at 70 +/

-5[deg]F (21 +/-2[deg]C) and 55% +/-10% relative humidity, for a

minimum of 24 hours prior to testing.

(e) Apparatus Calibration.

(1) With the sliding platform out of the chamber, install the

calorimeter holding frame. Push the platform back into the chamber

and insert the calorimeter into the first hole (``zero'' position).

See figure 7. Close the bottom door located below the sliding

platform. The distance from the centerline of the calorimeter to the

radiant panel surface at this point must be 7.\1/2\ inches +/-\1/8\

(191 mm +/-3). Prior to igniting the radiant panel, ensure that the

calorimeter face is clean and that there is water running through

the calorimeter.

(2) Ignite the panel. Adjust the fuel/air mixture to achieve 1.5

BTUs/ft\2\-second +/-5% (1.7 Watts/cm\2\ +/-5%) at the ``zero''

position. If using an electric panel, set the power controller to

achieve the proper heat flux. Allow the unit to reach steady state

(this may take up to 1 hour). The pilot burner must be off and in

the down position during this time.

(3) After steady-state conditions have been reached, move the

calorimeter 2 inches (51 mm) from the ``zero'' position (first hole)

to position 1 and record the heat flux. Move the calorimeter to

position 2 and record the heat flux. Allow enough time at each

position for the calorimeter to stabilize. Table 1 depicts typical

calibration values at the three positions.

Table 1.--Calibration Table

------------------------------------------------------------------------

Position BTU's/ft\2\sec Watts/cm\2\

------------------------------------------------------------------------

``Zero'' Position........... 1.5 1.7

Position 1.................. 1.51-1.50-1.49 1.71-1.70-1.69

Position 2.................. 1.43-1.44 1.62-1.63

------------------------------------------------------------------------

[[Page 45068]]

(4) Open the bottom door, remove the calorimeter and holder

fixture. Use caution as the fixture is very hot.

(f) Test Procedure.

(1) Ignite the pilot burner. Ensure that it is at least 2 inches

(51 mm) above the top of the platform. The burner must not contact

the specimen until the test begins.

(2) Place the test specimen in the sliding platform holder.

Ensure that the test sample surface is level with the top of the

platform. At ``zero'' point, the specimen surface must be 7\1/2\

inches +/-\1/8\ inch (191 mm +/-3) below the radiant panel.

(3) Place the retaining/securing frame over the test specimen.

It may be necessary (due to compression) to adjust the sample (up or

down) in order to maintain the distance from the sample to the

radiant panel (7\1/2\ inches +/-\1/8\ inch (191 mm+/-3) at ``zero''

position). With film/fiberglass assemblies, it is critical to make a

slit in the film cover to purge any air inside. This allows the

operator to maintain the proper test specimen position (level with

the top of the platform) and to allow ventilation of gases during

testing. A longitudinal slit, approximately 2 inches (51mm) in

length, must be centered 3 inches +/-\1/2\ inch (76mm+/-13mm) from

the left flange of the securing frame. A utility knife is acceptable

for slitting the film cover.

(4) Immediately push the sliding platform into the chamber and

close the bottom door.

(5) Bring the pilot burner flame into contact with the center of

the specimen at the ``zero'' point and simultaneously start the

timer. The pilot burner must be at a 27[deg] angle with the sample

and be approximately \1/2\ inch (12 mm) above the sample. See figure

7. A stop, as shown in figure 8, allows the operator to position the

burner correctly each time.

[GRAPHIC] [TIFF OMITTED] TR31JY03.011

(6) Leave the burner in position for 15 seconds and then remove

to a position at least 2 inches (51 mm) above the specimen.

(g) Report.

(1) Identify and describe the test specimen.

(2) Report any shrinkage or melting of the test specimen.

(3) Report the flame propagation distance. If this distance is

less than 2 inches, report this as a pass (no measurement required).

(4) Report the after-flame time.

(h) Requirements.

(1) There must be no flame propagation beyond 2 inches (51 mm)

to the left of the centerline of the pilot flame application.

(2) The flame time after removal of the pilot burner may not

exceed 3 seconds on any specimen.

Part VII--Test Method To Determine the Burnthrough Resistance of

Thermal/Acoustic Insulation Materials

Use the following test method to evaluate the burnthrough

resistance characteristics of aircraft thermal/acoustic insulation

materials when exposed to a high intensity open flame.

(a) Definitions.

Burnthrough time means the time, in seconds, for the burner

flame to penetrate the test specimen, and/or the time required for

the heat flux to reach 2.0 Btu/ft2sec (2.27 W/

cm2) on the inboard side, at a distance of 12 inches

(30.5 cm) from the front surface of the insulation blanket test

frame, whichever is sooner. The burnthrough time is measured at the

inboard side of each of the insulation blanket specimens.

Insulation blanket specimen means one of two specimens

positioned in either side of

[[Page 45069]]

the test rig, at an angle of 30[deg] with respect to vertical.

Specimen set means two insulation blanket specimens. Both

specimens must represent the same production insulation blanket

construction and materials, proportioned to correspond to the

specimen size.

(b) Apparatus.

(1) The arrangement of the test apparatus is shown in figures 1

and 2 and must include the capability of swinging the burner away

from the test specimen during warm-up.

[[Page 45070]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.012

[[Page 45071]]

(2) Test burner. The test burner must be a modified gun-type

such as the Park Model DPL 3400. Flame characteristics are highly

dependent on actual burner setup. Parameters such as fuel pressure,

nozzle depth, stator position, and intake airflow must be properly

adjusted to achieve the correct flame output.

[GRAPHIC] [TIFF OMITTED] TR31JY03.013

[[Page 45072]]

(i) Nozzle. A nozzle must maintain the fuel pressure to yield a

nominal 6.0 gal/hr (0.378 L/min) fuel flow. A Monarch-manufactured

80[deg] PL (hollow cone) nozzle nominally rated at 6.0 gal/hr at 100

lb/in2 (0.71 MPa) delivers a proper spray pattern.

(ii) Fuel Rail. The fuel rail must be adjusted to position the

fuel nozzle at a depth of 0.3125 inch (8 mm) from the end plane of

the exit stator, which must be mounted in the end of the draft tube.

(iii) Internal Stator. The internal stator, located in the

middle of the draft tube, must be positioned at a depth of 3.75

inches (95 mm) from the tip of the fuel nozzle. The stator must also

be positioned such that the integral igniters are located at an

angle midway between the 10 and 11 o'clock position, when viewed

looking into the draft tube. Minor deviations to the igniter angle

are acceptable if the temperature and heat flux requirements conform

to the requirements of paragraph VII(e) of this appendix.

(iv) Blower Fan. The cylindrical blower fan used to pump air

through the burner must measure 5.25 inches (133 mm) in diameter by

3.5 inches (89 mm) in width.

(v) Burner cone. Install a 12 +0.125-inch (305 +/-3 mm) burner

extension cone at the end of the draft tube. The cone must have an

opening 6 +/-0.125-inch (152 +/-3 mm) high and 11 +/-0.125-inch (280

+/-3 mm) wide (see figure 3).

(vi) Fuel. Use JP-8, Jet A, or their international equivalent,

at a flow rate of 6.0 +/-0.2 gal/hr (0.378 +/-0.0126 L/min). If this

fuel is unavailable, ASTM K2 fuel (Number 2 grade kerosene) or ASTM

D2 fuel (Number 2 grade fuel oil or Number 2 diesel fuel) are

acceptable if the nominal fuel flow rate, temperature, and heat flux

measurements conform to the requirements of paragraph VII(e) of this

appendix.

(vii) Fuel pressure regulator. Provide a fuel pressure

regulator, adjusted to deliver a nominal 6.0 gal/hr (0.378 L/min)

flow rate. An operating fuel pressure of 100 lb/in\2\ (0.71 MPa) for

a nominally rated 6.0 gal/hr 80[deg] spray angle nozzle (such as a

PL type) delivers 6.0 +/-0.2 gal/hr (0.378 +/-0.0126 L/min).

[[Page 45073]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.014

[[Page 45074]]

(3) Calibration rig and equipment.

(i) Construct individual calibration rigs to incorporate a

calorimeter and thermocouple rake for the measurement of heat flux

and temperature. Position the calibration rigs to allow movement of

the burner from the test rig position to either the heat flux or

temperature position with minimal difficulty.

(ii) Calorimeter. The calorimeter must be a total heat flux,

foil type Gardon Gage of an appropriate range such as 0-20 Btu/ft

\2\-sec (0-22.7 W/cm \2\), accurate to +/-3% of the indicated

reading. The heat flux calibration method must be in accordance with

paragraph VI(b)(7) of this appendix.

(iii) Calorimeter mounting. Mount the calorimeter in a 6- by 12-

+/-0.125 inch (152- by 305- +/-3 mm) by 0.75 +/-0.125 inch (19 mm +/

-3 mm) thick insulating block which is attached to the heat flux

calibration rig during calibration (figure 4). Monitor the

insulating block for deterioration and replace it when necessary.

Adjust the mounting as necessary to ensure that the calorimeter face

is parallel to the exit plane of the test burner cone.

[[Page 45075]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.015

[[Page 45076]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.016

[[Page 45077]]

(iv) Thermocouples. Provide seven \1/8\-inch (3.2 mm) ceramic

packed, metal sheathed, type K (Chromel-alumel), grounded junction

thermocouples with a nominal 24 American Wire Gauge (AWG) size

conductor for calibration. Attach the thermocouples to a steel angle

bracket to form a thermocouple rake for placement in the calibration

rig during burner calibration (figure 5).

(v) Air velocity meter. Use a vane-type air velocity meter to

calibrate the velocity of air entering the burner. An Omega

Engineering Model HH30A is satisfactory. Use a suitable adapter to

attach the measuring device to the inlet side of the burner to

prevent air from entering the burner other than through the

measuring device, which would produce erroneously low readings. Use

a flexible duct, measuring 4 inches wide (102 mm) by 20 feet long

(6.1 meters), to supply fresh air to the burner intake to prevent

damage to the air velocity meter from ingested soot. An optional

airbox permanently mounted to the burner intake area can effectively

house the air velocity meter and provide a mounting port for the

flexible intake duct.

(4) Test specimen mounting frame. Make the mounting frame for

the test specimens of \1/8\-inch (3.2 mm) thick steel as shown in

figure 1, except for the center vertical former, which should be \1/

4\-inch (6.4 mm) thick to minimize warpage. The specimen mounting

frame stringers (horizontal) should be bolted to the test frame

formers (vertical) such that the expansion of the stringers will not

cause the entire structure to warp. Use the mounting frame for

mounting the two insulation blanket test specimens as shown in

figure 2.

(5) Backface calorimeters. Mount two total heat flux Gardon type

calorimeters behind the insulation test specimens on the back side

(cold) area of the test specimen mounting frame as shown in figure

6. Position the calorimeters along the same plane as the burner cone

centerline, at a distance of 4 inches (102 mm) from the vertical

centerline of the test frame.

[[Page 45078]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.017

[[Page 45079]]

(i) The calorimeters must be a total heat flux, foil type Gardon

Gage of an appropriate range such as 0-5 Btu/ft2-sec (0-

5.7 W/cm2), accurate to +/-3% of the indicated reading.

The heat flux calibration method must comply with paragraph VI(b)(7)

of this appendix.

(6) Instrumentation. Provide a recording potentiometer or other

suitable calibrated instrument with an appropriate range to measure

and record the outputs of the calorimeter and the thermocouples.

(7) Timing device. Provide a stopwatch or other device, accurate

to +/-1%, to measure the time of application of the burner flame and

burnthrough time.

(8) Test chamber. Perform tests in a suitable chamber to reduce

or eliminate the possibility of test fluctuation due to air

movement. The chamber must have a minimum floor area of 10 by 10

feet (305 by 305 cm).

(i) Ventilation hood. Provide the test chamber with an exhaust

system capable of removing the products of combustion expelled

during tests.

(c) Test Specimens.

(1) Specimen preparation. Prepare a minimum of three specimen

sets of the same construction and configuration for testing.

(2) Insulation blanket test specimen.

(i) For batt-type materials such as fiberglass, the constructed,

finished blanket specimen assemblies must be 32 inches wide by 36

inches long (81.3 by 91.4 cm), exclusive of heat sealed film edges.

(ii) For rigid and other non-conforming types of insulation

materials, the finished test specimens must fit into the test rig in

such a manner as to replicate the actual in-service installation.

(3) Construction. Make each of the specimens tested using the

principal components (i.e., insulation, fire barrier material if

used, and moisture barrier film) and assembly processes

(representative seams and closures).

(i) Fire barrier material. If the insulation blanket is

constructed with a fire barrier material, place the fire barrier

material in a manner reflective of the installed arrangement For

example, if the material will be placed on the outboard side of the

insulation material, inside the moisture film, place it the same way

in the test specimen.

(ii) Insulation material. Blankets that utilize more than one

variety of insulation (composition, density, etc.) must have

specimen sets constructed that reflect the insulation combination

used. If, however, several blanket types use similar insulation

combinations, it is not necessary to test each combination if it is

possible to bracket the various combinations.

(iii) Moisture barrier film. If a production blanket

construction utilizes more than one type of moisture barrier film,

perform separate tests on each combination. For example, if a

polyimide film is used in conjunction with an insulation in order to

enhance the burnthrough capabilities, also test the same insulation

when used with a polyvinyl fluoride film.

(iv) Installation on test frame. Attach the blanket test

specimens to the test frame using 12 steel spring type clamps as

shown in figure 7. Use the clamps to hold the blankets in place in

both of the outer vertical formers, as well as the center vertical

former (4 clamps per former). The clamp surfaces should measure 1

inch by 2 inches (25 by 51 mm). Place the top and bottom clamps 6

inches (15.2 cm) from the top and bottom of the test frame,

respectively. Place the middle clamps 8 inches (20.3 cm) from the

top and bottom clamps.

[[Page 45080]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.018

[[Page 45081]]

(Note: For blanket materials that cannot be installed in

accordance with figure 7 above, the blankets must be installed in a

manner approved by the FAA.)

(v) Conditioning. Condition the specimens at 70[deg] +/-5[deg]F

(21[deg] +/-2[deg]C) and 55% +/-10% relative humidity for a minimum

of 24 hours prior to testing.

(d) Preparation of apparatus.

(1) Level and center the frame assembly to ensure alignment of

the calorimeter and/or thermocouple rake with the burner cone.

(2) Turn on the ventilation hood for the test chamber. Do not

turn on the burner blower. Measure the airflow of the test chamber

using a vane anemometer or equivalent measuring device. The vertical

air velocity just behind the top of the upper insulation blanket

test specimen must be 100 +/-50 ft/min (0.51 +/-0.25 m/s). The

horizontal air velocity at this point must be less than 50 ft/min

(0.25 m/s).

(3) If a calibrated flow meter is not available, measure the

fuel flow rate using a graduated cylinder of appropriate size. Turn

on the burner motor/fuel pump, after insuring that the igniter

system is turned off. Collect the fuel via a plastic or rubber tube

into the graduated cylinder for a 2-minute period. Determine the

flow rate in gallons per hour. The fuel flow rate must be 6.0 +/-0.2

gallons per hour (0.378 +/-0.0126 L/min).

(e) Calibration.

(1) Position the burner in front of the calorimeter so that it

is centered and the vertical plane of the burner cone exit is 4 +/-

0.125 inches (102 +/-3 mm) from the calorimeter face. Ensure that

the horizontal centerline of the burner cone is offset 1 inch below

the horizontal centerline of the calorimeter (figure 8). Without

disturbing the calorimeter position, rotate the burner in front of

the thermocouple rake, such that the middle thermocouple (number 4

of 7) is centered on the burner cone.

[[Page 45082]]

[GRAPHIC] [TIFF OMITTED] TR31JY03.019

[[Page 45083]]

Ensure that the horizontal centerline of the burner cone is also

offset 1 inch below the horizontal centerline of the thermocouple

tips. Re-check measurements by rotating the burner to each position

to ensure proper alignment between the cone and the calorimeter and

thermocouple rake. (Note: The test burner mounting system must

incorporate ``detents'' that ensure proper centering of the burner

cone with respect to both the calorimeter and the thermocouple

rakes, so that rapid positioning of the burner can be achieved

during the calibration procedure.)

(2) Position the air velocity meter in the adapter or airbox,

making certain that no gaps exist where air could leak around the

air velocity measuring device. Turn on the blower/motor while

ensuring that the fuel solenoid and igniters are off. Adjust the air

intake velocity to a level of 2150 ft/min, (10.92 m/s) then turn off

the blower/motor. (Note: The Omega HH30 air velocity meter measures

2.625 inches in diameter. To calculate the intake airflow, multiply

the cross-sectional area (0.03758 ft2) by the air

velocity (2150 ft/min) to obtain 80.80 ft3/min. An air

velocity meter other than the HH30 unit can be used, provided the

calculated airflow of 80.80 ft3/min (2.29 m3/

min) is equivalent.)

(3) Rotate the burner from the test position to the warm-up

position. Prior to lighting the burner, ensure that the calorimeter

face is clean of soot deposits, and there is water running through

the calorimeter. Examine and clean the burner cone of any evidence

of buildup of products of combustion, soot, etc. Soot buildup inside

the burner cone may affect the flame characteristics and cause

calibration difficulties. Since the burner cone may distort with

time, dimensions should be checked periodically.

(4) While the burner is still rotated to the warm-up position,

turn on the blower/motor, igniters and fuel flow, and light the

burner. Allow it to warm up for a period of 2 minutes. Move the

burner into the calibration position and allow 1 minute for

calorimeter stabilization, then record the heat flux once every

second for a period of 30 seconds. Turn off burner, rotate out of

position, and allow to cool. Calculate the average heat flux over

this 30-second duration. The average heat flux should be 16.0 +/-0.8

Btu/ft2 sec (18.2 +/-0.9 W/cm \2\).

(5) Position the burner in front of the thermocouple rake. After

checking for proper alignment, rotate the burner to the warm-up

position, turn on the blower/motor, igniters and fuel flow, and

light the burner. Allow it to warm up for a period of 2 minutes.

Move the burner into the calibration position and allow 1 minute for

thermocouple stabilization, then record the temperature of each of

the 7 thermocouples once every second for a period of 30 seconds.

Turn off burner, rotate out of position, and allow to cool.

Calculate the average temperature of each thermocouple over this 30-

second period and record. The average temperature of each of the 7

thermocouples should be 1900[deg]F +/- 100[deg]F (1038 +/-

56[deg]C).

(6) If either the heat flux or the temperatures are not within

the specified range, adjust the burner intake air velocity and

repeat the procedures of paragraphs (4) and (5) above to obtain the

proper values. Ensure that the inlet air velocity is within the

range of 2150 ft/min +/-50 ft/min (10.92 +/-0.25 m/s).

(7) Calibrate prior to each test until consistency has been

demonstrated. After consistency has been confirmed, several tests

may be conducted with calibration conducted before and after a

series of tests.

(f) Test procedure.

(1) Secure the two insulation blanket test specimens to the test

frame. The insulation blankets should be attached to the test rig

center vertical former using four spring clamps positioned as shown

in figure 7 (according to the criteria of paragraph (c)(4) or

(c)(4)(i) of this part of this appendix).

(2) Ensure that the vertical plane of the burner cone is at a

distance of 4 +/-0.125 inch (102 +/-3 mm) from the outer surface of

the horizontal stringers of the test specimen frame, and that the

burner and test frame are both situated at a 30[deg] angle with

respect to vertical.

(3) When ready to begin the test, direct the burner away from

the test position to the warm-up position so that the flame will not

impinge on the specimens prematurely. Turn on and light the burner

and allow it to stabilize for 2 minutes.

(4) To begin the test, rotate the burner into the test position

and simultaneously start the timing device.

(5) Expose the test specimens to the burner flame for 4 minutes

and then turn off the burner. Immediately rotate the burner out of

the test position.

(6) Determine (where applicable) the burnthrough time, or the

point at which the heat flux exceeds 2.0 Btu/ft2-sec

(2.27 W/cm2).

(g) Report.

(1) Identify and describe the specimen being tested.

(2) Report the number of insulation blanket specimens tested.

(3) Report the burnthrough time (if any), and the maximum heat

flux on the back face of the insulation blanket test specimen, and

the time at which the maximum occurred.

(h) Requirements.

(1) Each of the two insulation blanket test specimens must not

allow fire or flame penetration in less than 4 minutes.

(2) Each of the two insulation blanket test specimens must not

allow more than 2.0 Btu/ft2-sec (2.27 W/cm2)

on the cold side of the insulation specimens at a point 12 inches

(30.5 cm) from the face of the test rig.

PART 91--GENERAL OPERATING AND FLIGHT RULES

0

4. The authority citation for part 91 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40103, 40113, 40120, 44101, 44111,

44701, 44709, 44711, 44712, 44715, 44716, 44717, 44722, 46306,

46315, 46316, 46502, 46504, 46506-46507, 47122, 47508, 47528-47531.

0

5. Amend Sec. 91.613 by redesignating the existing text as paragraph

(a), and adding paragraph (b) to read as follows:

Sec. 91.613 Materials for compartment interiors.

* * * * *

(b) Thermal/acoustic insulation materials. For transport category

airplanes type certificated after January 1, 1958:

(1) For airplanes manufactured before September 2, 2005, when

thermal/acoustic insulation materials are installed in the fuselage as

replacements after September 2, 2005, those materials must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

(2) For airplanes manufactured after September 2, 2005, thermal/

acoustic insulation materials installed in the fuselage must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

PART 121--OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL

OPERATIONS

0

6. The authority citation for part 121 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 40119, 44101, 44701-44702,

44705, 44709-44711, 44713, 44716-44717, 44722, 44901, 44903-44904,

44912, 46105.

0

7. Amend Sec. 121.312 by adding paragraph (e) to read as follows:

Sec. 121.312 Materials for compartment interiors.

* * * * *

(e) Thermal/acoustic insulation materials. For transport category

airplanes type certificated after January 1, 1958:

(1) For airplanes manufactured before September 2, 2005, when

thermal/acoustic insulation materials are installed in the fuselage as

replacements after September 2, 2005, those materials must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

(2) For airplanes manufactured after September 2, 2005, thermal/

acoustic insulation materials installed in the fuselage must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

(3) For airplanes with a passenger capacity of 20 or greater,

manufactured after September 3, 2007, thermal/acoustic insulation

materials installed in the lower half of the fuselage must meet the

flame penetration resistance requirements of Sec. 25.856 of this

chapter, effective September 2, 2003.

[[Page 45084]]

PART 125--CERTIFICATION AND OPERATIONS: AIRPLANES HAVING A SEATING

CAPACITY OF 20 OR MORE PASSENGERS OR A MAXIMUM PAYLOAD CAPACITY OF

6,000 POUNDS OR MORE

0

8. The authority citation for part 125 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44705, 44710-

44711, 44713, 44716-44717, 44722.

0

9. Amend Sec. 125.113 by adding paragraph (c) to read as follows:

Sec. 125.113 Cabin interiors.

* * * * *

(c) Thermal/acoustic insulation materials. For transport category

airplanes type certificated after January 1, 1958:

(1) For airplanes manufactured before September 2, 2005, when

thermal/acoustic insulation materials are installed in the fuselage as

replacements after September 2, 2005, those materials must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

(2) For airplanes manufactured after September 2, 2005, thermal/

acoustic insulation materials installed in the fuselage must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

PART 135--OPERATING REQUIREMENTS: COMMUTER AND ON-DEMAND OPERATIONS

AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT

0

10. The authority citation for part 135 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44705, 44709,

44711-44713, 44715-44717, 44722.

0

11. Amend Sec. 135.170 by adding paragraph (c) to read as follows:

Sec. 135.170 Materials for compartment interiors.

* * * * *

(c) Thermal/acoustic insulation materials. For transport category

airplanes type certificated after January 1, 1958:

(1) For airplanes manufactured before September 2, 2005, when

thermal/acoustic insulation materials are installed in the fuselage as

replacements after September 2, 2005, those materials must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

(2) For airplanes manufactured after September 2, 2005, thermal/

acoustic insulation materials installed in the fuselage must meet the

flame propagation requirements of Sec. 25.856 of this chapter,

effective September 2, 2003.

Issued in Washington, DC on July 14, 2003.

Marion Blakey,

Administrator.

[FR Doc. 03-18612 Filed 7-30-03; 8:45 am]

BILLING CODE 4910-13-P