Improved Flammability Standards for Materials Used in the Interiors of Transport Category Airplane Cabins

SUMMARY: These amendments clarify standards adopted in 1986 concerning

the flammability of components used in the cabins of certain transport

category airplanes. This action is being taken to preclude costly,

unintended changes to airplane interiors. The clarifications, which are

applicable to air carriers, air taxi operators and commercial

operators, as well as manufacturers of such airplanes, will result in

more appropriate, consistent application of those standards.

EFFECTIVE DATE: March 6, 1995.

FOR FURTHER INFORMATION CONTACT: Gary L. Killion, Manager, Regulations

Branch, ANM-114, Transport Airplane Directorate, Aircraft Certification

Service, FAA, 1601 Lind Avenue Southwest, Renton, Washington 98055-

4056; telephone (206) 227-2114.

SUPPLEMENTARY INFORMATION:

Background

These amendments are based on Notice of Proposed Rulemaking (NPRM)

90-12, that was published in the Federal Register on April 12, 1990 (55

FR 13886).

As discussed in the notice, Amendments 25-61 and 121-189 (51 FR

26206, July 26, 1986) were adopted to upgrade the flammability

standards for materials used in the interiors of transport category

airplanes. The improved flammability standards were developed following

a research and development program managed and conducted primarily at

the FAA Technical Center in Atlantic City, New Jersey, to study

aircraft fire characteristics and develop practical test methods. Among

the tests conducted at the Technical Center were full-scale fire tests

using the fuselage of a military C-133 configured to represent a wide-

body jet transport airplane. The test conditions simulated

representative post-crash external fuel-fed fires. Numerous laboratory

tests were also conducted to correlate possible material qualification

test methods with the full-scale tests. As a result of those tests, the

Ohio State University (OSU) radiant rate-of-heat-release apparatus was

determined to be the most suitable for material qualification. These

tests led to the adoption of Amendment 25-61.

Amendment 25-61 established flammability standards for transport

category airplanes with passenger seating capacities of 20 or more and

specified the test method and apparatus to be used in showing

compliance with those standards. It specified that interior ceiling and

wall panels (other than lighting lenses), partitions, and the outer

surfaces of galleys, large cabinets and stowage compartments (other

than underseat stowage compartments and compartments for stowing small

items such as magazines and maps) must meet the new standards. As

outlined in the amendment, an average of three or more test specimens

must not exceed 65 kilowatts per square meter peak heat release nor 65

kilowatt minutes per square meter total heat release during the first

two minutes of sample exposure time (65/65) when tested using the OSU

test apparatus. These acceptance criteria were chosen in order to

produce a significant retardation of the flashover event which controls

occupant survivability, as experienced in the full-scale testing.

(Burning cabin materials give off unburned gases that collect in the

upper portions of the cabin. After a very short time, these unburned

gases are heated to the point where they ignite and burn

instantaneously. When this occurs, the temperature in the whole cabin

becomes so hot that survival is impossible for anyone remaining in the

cabin. This phenomenon, known as flashover, also makes further survival

impossible by consuming the oxygen in the cabin.)

Because Amendment 25-61 applies explicitly only to airplanes for

which an application for type certificate is made after August 20,

1986, Amendment 121-189 to Part 121 of the FAR was also adopted to

require operators of certain other airplanes used in air carrier or

commercial service to meet the new 65/65 standards. Those airplanes

must meet the new standards if they were newly manufactured after

August 19, 1990. Airplanes type certificated on or after January 1,

1958, and manufactured prior to August 20, 1990, must also comply with

the new standards upon the first substantially complete replacement of

the specified cabin interior components on or after the latter date.

Although Part 135 was not amended at that time, air taxi and

commercial operators of large airplanes are required to comply as well

because Sec. 135.169 incorporated the newly adopted provisions of Part

121 by reference.

At the time the amendments were adopted, the FAA understood that

some persons were planning to install components which, even though

they would meet the previously existing requirements of Part 25 for

flammability, were more flammable than the components that were in

general use at that time. In order to preclude a possible degradation

in the flammability characteristics of the cabin interiors, Amendment

121-189 also established interim standards of 100 kilowatts per square

meter peak heat release and 100 kilowatt minutes per square meter total

heat release (100/100). The interim standards are applicable to

airplanes manufactured during the two-year period prior to August 20,

1990; and, unless there is a substantially complete replacement of the

specified cabin interior components after August 19, 1990, they will

remain applicable to those airplanes as long as they are operated under

the provisions of Part 121 or Part 135. (If there is a substantially

complete replacement on or after August 19, 1990, the definitive 65/65

standards would be applicable.) In addition, the interim standards are

also applicable to airplanes in which there is a substantially complete

replacement of the specified interior components during that two-year

period.

Prior to the adoption of Amendment 121-189, Sec. 121.312 required

certain airplanes to meet earlier flammability standards upon the first

substantially complete replacement of the cabin interior. (Note that

this earlier rulemaking refers to a substantially complete replacement

of all cabin interior components, while the later rulemaking refers to

a substantially complete replacement of the specified interior

components. Whether certain other interior components, e.g., seat

cushions and flooring, are replaced is not relevant to whether there is

a substantially complete replacement in the latter case. Also, the

earlier rulemaking applies to all airplanes while the later rulemaking

applies only to airplanes with 20 or more passengers.) This earlier

requirement is partially superseded if there is a substantially

complete replacement of the interior components specified in

Sec. 25.853 (a-l) after August 19, 1988. It does, however, remain

applicable insofar as interior components not specified in

Sec. 25.853(a-l) are concerned. The earlier requirement also remains

applicable to airplanes in which there has not been a substantially

complete

[[Page 6617]]

replacement of the cabin interior since August 19, 1988, and to

airplanes with 19 or fewer passengers.

The date of manufacture, as used in Sec. 121.312, is 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 to 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.

For reasons discussed in the preamble to that amendment, Amendment

25-66 was adopted (53 FR 37542, September 27, 1988) to make minor

refinements in the test procedures and apparatus required to show

compliance with the standards adopted by Amendment 25-61 and to add a

requirement for smoke testing. Amendment 121-198, which was adopted at

the same time, added a provision allowing deviations to be granted for

certain components.

In the preamble to Amendment 25-61, the FAA noted that the new heat

release standards apply to all large-surface cabin interior components,

such as sidewalls, ceilings, bins and partitions, and galley

structures. It was also noted that the new standards do not apply to

smaller items because their small masses would preclude significant

contributions to the total heat release in the cabin area. The FAA has

received a number of requests for clarification as to the maximum size

a component may be without having to comply with the new heat release

standards.

The distinction between parts with large surface areas, which must

meet the new standards, and those with smaller surface areas is very

difficult because of the size of the cabin and other factors that may

vary from one airplane to another. For example, a specific component

might be insignificant when installed in a large wide-body airplane

because it would make a minor contribution to the overall flammability

of the area of the cabin in which it is installed. On the other hand,

it might represent a major contribution when installed in a smaller

transport category airplane. The proximity of the component to a

potential source of fire, such as an exit or galley, is also a

consideration. It is not possible to cite a specific size that will

apply in all installations; however, as a general rule, components with

exposed-surface areas of one square foot or less may be considered

small enough that they do not have to meet the new standards.

Components with exposed-surface areas greater than two square feet may

be considered large enough that they do have to meet the new standards.

Those with exposed-surface areas greater than one square foot, but less

than two square feet, must be considered in conjunction with the areas

of the cabin in which they are installed before a determination could

be made.

Discussion

Since the time Amendments 25-61 and 121-189 were adopted, the FAA

became aware of four areas in which the wording of the new rules does

not clearly reflect the intent of the agency as discussed in the

preamble to those amendments. Because the new rules do not clearly

reflect the intent in those areas and because the comments that were

received may have been based on the intent, as expressed in the

preambles, rather than the literal wording of the rules, the following

clarifications were proposed in Notice 90-12.

Cabin windows and clear vision panels in cabin partitions: The

preamble to Amendments 25-61 and 121-189 states, ``The new flammability

standards do not apply to transparent or translucent components such as

lenses used in interior lights and illuminated signs, and window anti-

scratch panels, because of the lack of materials which will meet the

flammability standards and still have the light transmissibility

characteristics which are vital in emergency situations.'' Although not

specifically mentioned in the earlier rulemaking, transparent panels

are sometimes inserted in cabin partitions to enhance cabin safety. For

example, they are sometimes used to provide seated flight attendants a

clear, unobstructed view of the cabin or to provide passengers a view

of an exit as an aid to an emergency evacuation. As in the case of

lighting lenses and windows, the need for transparent partition panels

that enhance cabin safety outweighs the increased safety provided by

components that meet the new flammability standards considering the

small area such transparencies would involve. In order to preclude

confusion concerning the applicability of the standards to such

transparent or translucent panels, Sec. 25.853(a-l) (1) and (2) were

proposed to read, ``Interior ceiling and wall panels, other than

lighting lenses and windows,'' and, ``Partitions, other than

transparent panels needed to enhance cabin safety,'' respectively. The

maximum size of a transparent panel would, of course, be limited to

that which is actually needed to enhance cabin safety.

It was noted that the FAA would consider further rulemaking to

require those components to meet the new flammability standards should

materials capable of meeting the new flammability standards and having

the necessary light transmissibility characteristics for use as

windows, etc., be developed later.

Galleys: As currently worded, Sec. 25.853(a-1) states that the new

flammability standards apply to the ``outer surfaces of galleys.'' This

phrase was intended to make an exception for the interior surfaces of

galley cabinets, etc., that would not be exposed to a cabin fire. It is

ambiguous, however, because most galleys are not isolated from the main

cabin by a door. While one might consider the surfaces of a galley

working are to be ``inner surfaces,'' they are actually outer surfaces

in most installations in the sense that they could be exposed to a

cabin fire. In addition, the inner walls of the galley cart cavity or

standard container cavity may also be exposed on some lightly loaded

flights when there is not a full complement of carts or containers on

board. In order to preclude any confusion in this regard, it was

proposed that Sec. 25.853(a-1) would be amended to clarify that any

galley surface exposed to the passenger cabin must meet the new

standards.

Isolated compartments: Unlike previously existing paragraphs (a)

and (b) of Sec. 25.853, the new flammability standards of paragraph (a-

1) were intended to apply only to the passenger cabin and not to

compartments that are isolated from the passenger cabin. Due, however,

to the organization of Sec. 25.853(a-1), if taken literally, the new

standards also pertain to each compartment occupied by crew (including

one occupied only on a temporary basis) or passengers regardless of

whether the particular compartment is isolated from the passenger

cabin.

Neither the research and development program nor the regulatory

evaluations on which the new flammability standards were based

considered that compartments isolated from the passenger cabin (or

cabins in the case of airplanes with passenger cabins located on two

different decks) would have to comply with the new standards. Unlike

most galleys located in the main cabin, remote galleys and other

compartments, such as lavatories, pilot compartments and crew rest or

sleeping areas, are generally isolated from the passenger cabin by at

least a door. In some instances, they are located on separate decks.

They would, therefore, not be exposed to a cabin fire until well after

[[Page 6618]]

flashover had occurred in the cabin and egress was no longer possible.

Should an external fire enter the airplane at one of those

compartments, the flammability of the materials used in them would not

directly affect the cabin due to their isolation. As stated in the

earlier rulemaking, the new standards address a post-crash, external

fuel-fed fire situation. With the exception of the pilot compartment,

it can be assumed that such compartments would not be occupied by

passengers or crewmembers during a post-crash situation.

Although the rulemaking was undertaken to address a post-crash

scenario, there is also the question of whether or not requiring the

lavatories to meet the new flammability standards would enhance safety

significantly in the event a fire originated in a lavatory during

flight. This question is particularly pertinent in light of the

recently adopted ban on smoking on domestic airline flights. Although

some persons might be more tempted to smoke illicitly in a lavatory

during such flights, the lavatory smoke detector required by recently

adopted Amendment 121-185 (50 FR 12726, March 29, 1985) serves as a

deterrent and provides warning of illicit smoking to the crew. In

addition, the new standards would not apply to many of the components

in a lavatory due to their small size. The doors and most sidewalls

have to meet the new standards regardless of whether the new standards

are applicable to lavatories because their outer sides also form

surfaces of the passenger cabin. Some portions of the lavatory are

generally constructed of fireproof stainless steel due to functional

considerations. Requiring the few remaining large components to meet

the new standards would have very little impact on the overall

flammability of the lavatory and would not significantly enhance safety

in the event of an inflight fire.

Pilot compartments are generally isolated from the passenger cabin

by a bulkhead and door. Although they are obviously occupied full-time,

requiring them to meet the new standards would not significantly

enhance safety in the event of an inflight fire for essentially the

same reasons. Pilot compartments are generally constructed of many

small components which would not have to meet the new standards due to

their small size. The bulkhead and entry door have to meet the new

standards regardless of whether they are applicable to the pilot

compartment because the aft sides of those components also form

surfaces of the passenger cabin. As in the case of the lavatories,

requiring the few remaining large components to meet the new standards

would have very little impact on the overall flammability of the pilot

compartment. Although there is no smoke detector required, a fire would

be detected immediately by the flight crewmembers. In addition, at

least one hand fire extinguisher must be conveniently located in the

pilot compartment in accordance with Sec. 25.851.(a)(6).

In view of these considerations, it was proposed that Sec. 25.853

would be amended to clarify that compartments that are isolated from

the cabin need not meet the standards. Sidewalls, doors etc., that

separate such compartments from the passenger cabin would, of course,

have to meet the new standards because their outer sides also form

surfaces of the passenger cabin.

Galley carts and other rotatable galley equipment: The earlier

rulemaking contained the statement, ``Service items, such as pillows or

blankets, magazines, food, and alcoholic beverages, are not part of the

certification process and would not have to meet the new flammability

standard.'' Galley carts are considered to be service items; however,

unlike the items cited in the preamble statement, they are generally

approved as part of the airplane type design. Although the new

flammability standards do not apply expressly to galley carts, it was

intended that they would apply implicitly to the extent that, when

stowed, the galley carts form exterior surfaces of the galley.

Typically, at least one end of each cart remains exposed and forms a

galley surface while the cart is stowed. In addition to galley carts,

these are galley standard containers used for various meal courses,

beverages, plates, etc., that also form galley surfaces when stowed.

Operators have pointed out that galley carts are removable items

that are rotated from one airplane to another with each flight. In this

regard, they note that their fleets will include older airplanes that

are not required to meet the new standards, as well as new airplanes

(or airplanes in which the interiors have been replaced) that will be

required to meet the new standards. They further note that the carts

are loaded before a flight by persons, usually independent caterers,

who have no way of knowing whether or not the airplane that will be

used on a particular flight is required to meet the new standards.

Unless all existing noncomplying galley carts are replaced with galley

carts that meet the new standards, there is no practical means to

ensure that galley carts meeting the new standards will be loaded on

the airplanes that are required to have them. It is estimated that

there are now approximately 125,000 galley carts in use with the U.S.

air carrier fleet. Typically, the cost per cart ranges from $800 to

$3,500; and the service life is about eight to ten years. While it is

feasible to replace the existing carts on an attrition basis, it would

be impractical to produce enough galley carts meeting the new standards

in time to meet the established deadlines. In addition, such immediate

replacement would be very costly. The operators note that they would

have commented accordingly had they not believed that, as service

items, galley carts did not have to meet the new standards.

The galley standard containers are also rotated from airplane to

airplane; and they, too, are filled prior to the flight by persons who

have no way of knowing whether the airplane that will be used on the

flight is one required to meet the new standards. While the cost of

each galley standard container would be less than that of a beverage

cart, replacing the entire inventory of containers would be very

costly.

Although it was intended that the exposed surfaces of stowed galley

carts and standard containers should meet the new standards, the FAA

has concluded, upon further review, that it was not clearly stated that

the galley carts and containers would be required to comply. The FAA

does, however, consider that the exposed surfaces of stowed galley

carts and standard containers must ultimately meet the new flammability

standards. It was, therefore, proposed that Sec. 25.853(a-1) would be

amended to specifically require the exposed surfaces of those

components to meet the new standards.

The FAA concurs that unless all carts and containers are replaced,

it would be extremely difficult to ensure that galley carts and

standard containers meeting the new standards are loaded on the

airplanes that are required to meet them. Furthermore, the immediate

replacement of all galley carts and standard containers would be

logistically impossible and would present an unreasonable economic

burden. If, on the other hand, galley carts and standard containers

that meet the new standards are acquired at a rate commensurate with

the rate at which new airplanes are acquired (and interiors of older

airplanes are replaced), it can be assumed that the overall level of

safety of the air carrier fleet will not be adversely affected by

intermixing carts and containers complying with the new standards with

those that do not. The small decrement of safety that would be suffered

due to

[[Page 6619]]

the use of noncomplying carts and containers in an airplane that must

meet the new standards would be compensated by an increment of safety

enjoyed due to the use of complying carts and containers in another

airplane that is not required to meet them. It was, therefore, proposed

that Sec. 121.312 would be amended to allow such intermixing of galley

carts and standard containers, provided that all carts and containers

manufactured after a specified date meet the new standards.

Other changes: Certain minor refinements in the test apparatus and

procedures were identified; and it was proposed that Appendix F of Part

25, including the associated figures, would be revised accordingly. The

proposed refinements would not preclude the use of materials previously

found to be acceptable under the new standards; nor enable the use of

materials previously found unacceptable; however, they would improve

the repeatability of test results from one test run to another and from

one laboratory to another. Other minor nonsubstantive editing changes

would be made for consistency in style. Nonsubstantive editing changes

would also be made to Sec. 25.853 for clarity.

It was also proposed that the organization and language of

Sec. 121.312(a) would be revised for clarity.

As noted above, Part 135 was not amended at the time the new

standards were adopted; however, they are equally applicable to Part

135 operators because Sec. 135.169(a) incorporates the provisions of

Sec. 121.312 by cross reference. Since that time, it has come to the

attention of the FAA that the practice of incorporating certain

provisions of Part 121 in Part 135 by cross reference may cause

confusion. In order to preclude any confusion in this regard, it was

proposed that Part 135 would be amended to include the new standards

explicitly rather than by reference. Because Part 135 operators are

already required to meet these standards due to the incorporation by

cross reference, this change would not place any additional burden on

any person.

The reference to ``November 26, 1987'' in Sec. 121.312(b) is no

longer relevant because that date has already passed. It would,

therefore, be removed for simplification. The redundant reference to

Appendix F of Part 25 would also be removed from Sec. 121.312(b) for

simplification and consistency with the editorial style used in

Sec. 121.312(a). (Appendix F, Part II, is incorporated by cross

reference in Sec. 25.853(c); and Appendix F, Part IV, is incorporated

by cross reference in Sec. 25.853(a-1).)

Since the time Notice 90-12 was issued, Amendment 25-72 was adopted

(55 FR 29756, July 20, 1990). Although no substantive changes to

Sec. 25.853 were adopted, the requirements of that section were

rearranged considerably for clarity, and the test acceptance criteria

formerly contained in that section were transferred to Part I of

Appendix F. It is, therefore, necessary to make a number of

nonsubstantive conforming changes for consistency with Sec. 25.853 in

its present format.

Among the changes made to Sec. 25.853 as a result of the adoption

of Amendment 25-72 was the transfer of the seat cushion flammability

standards from former Sec. 25.853(c) to new Sec. 25.853(b). It has been

brought to the attention of the FAA that this change is causing

considerable confusion.

Seats are frequently transferred from one airplane to another;

therefore, as a practical matter, they must be marked to show that

their cushions comply with the flammability standards. With the change

in section number, the previous markings indicating compliance with

Sec. 25.853(c) are no longer accurate. In order to eliminate further

confusion in that regard, Sec. 25.853(b) has been marked ``Reserved,''

and the seat cushion flammability standards have been transferred back

to Sec. 25.853(c).

For convenience, the proposed changes to Sec. 25.853 are discussed

below both in terms of their identity in Notice 90-12 and as rearranged

for conformity with the changes resulting from the adoption of

Amendment 25-72.

Discussion of Comments

Seven commenters responded to the request for comments contained in

Notice 90-12. These included manufacturers, a foreign airworthiness

authority, and organizations representing manufacturers, airlines, and

airline employees.

One commenter notes that the restructuring and numbering of

Sec. 25.853 may have inadvertently excluded such items as lighting

lenses, windows, transparent panels needed to enhance cabin safety,

etc., from compliance with any of the flammability standards of

Sec. 25.853. The FAA concurs that the wording proposed in Notice 90-12

could have led to an incorrect interpretation of that nature. Section

25.853 is, therefore, changed by transferring the statement ``Except as

provided * * *'' to Sec. 25.853(d), which would have been

Sec. 25.853(a-1) as proposed in Notice 90-12.

One commenter opposes the proposal to clarify that compartments

isolated from the cabin are not required to meet the heat release

standards of Sec. 25.853(a-l). The commenter states that all

compartment components should be of the same standard and that meeting

the same standard would ensure that the net amount of material

contributing to fire development and propagation is at the absolute

minimum. In that regard, the commenter cites the accident involving a

McDonnell Douglas DC-9 operated by Air Canada on June 2, 1983, at the

Greater Cincinnati Airport, Covington, Kentucky. The commenter notes

that, while the origin of the fire that destroyed the airplane could

not be identified, the lavatory compartment's interior material was the

primary source of fuel and that the fire burned undetected for almost

15 minutes before the smoke was first noticed. The commenter asserts

that requiring the compartment to meet the same low heat release

standards as the main cabin would significantly reduce the amount of

fuel available for such a fire.

Contrary to the commenter's assertion, requiring all lavatory

components to meet the new standards for heat release would not

significantly reduce the amount of fuel available for a fire

originating in the lavatory. As noted above under Background, the heat

release standards do not apply to small surface-area components. As

further noted above under Discussion, many of the components in the

lavatory are small enough that they would not have to meet the new

standards in any event. The doors and most sidewalls have to meet the

new standards regardless of whether the new standards are applicable to

lavatories because their outer sides also form surfaces of the

passenger cabin. Some portions of the lavatory are generally

constructed of stainless steel due to functional considerations.

Stainless steel is, of course, fireproof. Requiring the few remaining

large components to meet the new standards would have very little

impact on the overall flammability of the lavatory and would not

significantly enhance safety in the event of an inflight fire.

In the accident cited by the commenter, smoke was discovered coming

from the left-hand lavatory in the aft cabin while the airplane was

enroute from Dallas, Texas to Montreal, Quebec. An emergency landing

was not made until 17 minutes later. By that time, the fire and smoke

had grown in intensity to the point that only half of the 46 occupants

were able to escape. As noted in their official accident report, NTSB/

AAR-86/02, the National Transportation Safety Board determined that the

probable causes of the accident were a fire of unknown origin, an

underestimate of the fire severity, and

[[Page 6620]]

misleading fire progress information provided to the captain.

Considering the few lavatory components that would be affected and the

time that the fire had been burning prior to the emergency landing, it

is unlikely that the outcome of the accident would have been more

favorable if the lavatory of that airplane had met the new heat release

standards.

Subsequent to the accident, the FAA adopted Amendments 25-58 and

121-183 (49 FR 43182, October 26, 1984), and 25-59 and 121-184 (49 FR

43188, October 26, 1984), that require, respectively, low-level

lighting to enable occupants to locate emergency exits in smoke-filled

cabins and new flammability standards for seat cushions. Unlike the

heat release standards of Amendment 25-61, the new flammability

standards for seat cushions are designed to slow the progression of a

fire through the cabin. The standards of Amendment 25-61 are, on the

other hand, designed to reduce the overall release of heat into the

cabin during a post-crash fire situation and provide more time for

egress before flashover makes further escape impossible. Amendment 121-

185 (50 FR 12726, March 29, 1985) was also adopted to require each

lavatory to be equipped with a smoke detection system, or equivalent,

and a fire extinguisher that discharges automatically upon the

occurrence of a fire in the trash receptacle. In addition, the

amendment requires the passenger cabins of certain airplanes to be

equipped with additional hand fire extinguishers, some of which must

contain the improved agent Halon 1211.

The commenter also notes that all compartments with essential

systems adjacent to their surfaces should be required to meet the heat

release standards of Sec. 25.853(a-1) in order to protect the essential

conductors of those systems from the high heat releases of burning

interior materials.

The commenter appears to be confusing the standards for heat

release with other standards for flame resistance. As noted above, the

heat release standards are designed to reduce the overall release of

heat into an area and thereby delay the time until flashover occurs. It

is assumed, on the other hand, that the insulation of electrical wiring

and cables could be enveloped by flame. They must, therefore, be tested

by actual application of flame to the insulation surface.

The same commenter recommends that, if an isolated compartment does

not have to meet the heat release standards, the doors separating the

compartment from the main cabin should be able to contain the heat and

smoke in the isolated compartment for at least five minutes. (Such

doors would be `fire-resistant' as defined in Part 1 of the FAR.)

The commenter's recommendation is apparently based on the

assumption that there will be an uncontrollable fire originating from

an isolated compartment. In view of the fire protection measures that

have been adopted for lavatories since the above noted accident, there

is no evident need for fire-resistant lavatory doors. Furthermore,

service history does not support a need for such doors to other

isolated compartments. The exception proposed as Sec. 25.853(a-2) is,

therefore, adopted as Sec. 25.853(e).

One commenter recommends that Sec. 25.853(a-1)(1) be amended to

read, ``other than lighting lenses, illuminated signs and windows,''

since illuminated signs are discussed in the preamble to Notice 90-12

as examples of excluded items. While it is true that the illuminated

portions of passenger information signs are not required to meet the

heat release standards of that section, it is not necessary to refer to

them specifically in Sec. 25.853(a-1)(1) because they are ``lighting

lenses.'' Proposed Sec. 25.853(a-1)(1) is adopted as Sec. 25.853(d)(1).

The same commenter and one other recommend that Sec. 25.853(a-2) be

clarified by adding ``lavatories'' to the list of compartments whose

interiors are excluded. Unlike the illuminated signs discussed above,

it may not be as clear that lavatories are considered isolated

compartments and, as such, are already excluded. Proposed

Sec. 25.853(a-2) is, therefore, changed to read, ``* * * such as pilot

compartments, galleys, lavatories, crew rest quarters, cabinets and

stowage compartments, * * *,'' and adopted as Sec. 25.853(e).

One commenter suggests that Sec. 25.853(a-2) should stipulate ``20

or more passengers.'' Since the only purpose of this paragraph, adopted

as paragraph (e), is to make an exception to paragraph (a-1), adopted

as paragraph (d), which is already so limited, there is no need to

repeat this limitation of applicability.

Because the flammability standards of Sec. 25.853(d), formerly

Sec. 25.853(a-1), are applicable only to airplanes with 20 or more

passengers, some persons have mistakenly assumed that the seat cushion

standards of Sec. 25.853(c) are also applicable only to airplanes with

20 or more passengers. To preclude any confusion in this regard, the

phrase, ``regardless of the passenger capacity of the airplane,'' has

been added to Sec. 25.853 (a) and (c).

Another commenter suggests that Part IV of Appendix F should be

amended to permit the use of the optional 14-hole upper pilot burner

that has been found satisfactory. Actually, the use of this optional

burner has already been accepted by the FAA under the equivalent safety

provisions of Sec. 21.21(b)(1). The FAA notes that test data obtained

during testing with the three-hole burner are sometimes invalidated

because the pilot burner would not remain lighted for the entire 5-

minute duration of the test. With the optional 14-hole burner, there is

a greater probability of reigniting any flamelets that might extinguish

during a test. Because the 14-hole burner may be preferable in some

instances, Part IV is amended to describe the optional use of that

burner, as suggested by the commenter. Testing with this optional

burner is already permitted under the equivalent safety provisions of

Sec. 21.21(b)(1); therefore, this is a minor nonsubstantive change that

places no additional burden on any person.

Paragraph (b)(8) states that the pilot burners must remain lighted

for the entire duration of the test. In regard to the difficulties

experienced in keeping the three-hole upper pilot burner lighted for

the entire duration of the test, the FAA proposed to add the statement,

``Intermittent pilot flame extinguishment for more than 3 seconds would

invalidate the test results.'' The same commenter notes that further

clarification is required. According to the commenter, it is normal for

some of the upper pilot-burner flamelets to be extinguished for periods

that can exceed three seconds when samples containing flame retardants

are tested. The commenter notes that the results of such tests have

been considered acceptable provided some of the flamelets have remained

lighted.

The FAA concurs that it is not necessary for each flamelet of the

three-hole upper pilot burner to remain lighted for the entire 5-minute

duration of the test; however, test results may be invalidated if two

flamelets are unlighted for more than 3 seconds. In order to preclude,

such intermittent flamelet extinguishment, the FAA has permitted

applicants to install an igniter. Intermittent flame extinguishment has

not posed a problem with the optional 14-hole upper pilot burner since

it was developed to preclude flame extinguishment. Paragraph (b)(8) is,

therefore, changed to read, ``Since intermittent pilot flame

extinguishment for more than 3 seconds would invalidate the test

results, a spark igniter may be installed to ensure that the burners

remain lighted.'' Paragraph

[[Page 6621]]

(e)(8), which is considered a more appropriate location than paragraph

(b)(8), is amended to clarify the requirements for burners and

flamelets to remain lighted.

Part IV, paragraph (e)(3) states that the proper air flow may be

set and monitored by either an orifice meter or a rotometer. Because of

difficulties experienced in setting and monitoring the air flow with a

rotometer, the FAA proposed in Notice 90-12 to amend that paragraph to

refer only to an orifice meter. The same commenter cited the successful

use of a rotometer by the National Research Council of Canada and

recommended that the reference to a rotormeter be retained in that

paragraph. While the use of a rotometer may be successful in some

instances, the FAA does not have sufficient information at this time to

conclude that a rotometer is acceptable on a general basis. It is,

therefore, not considered appropriate to specifically cite the

rotormeter in that paragraph as an acceptable alternative means of

setting and monitoring air flow. The FAA does recognize, however, that

rotometers, or any other devices for that matter, may be improved to

the point that their use is acceptable. In that event, those devices

could be used under the equivalent safety provisions of

Sec. 21.21(b)(1).

The same commenter notes that the area of .02323 m2 specified

in the heat release equation of paragraph (f)(2) is based on a test

specimen size of 6 x 6 inches. Since the actual size of the sample is

150 x 150 mm, the commenter believes that an area factor of .0225

m2 should actually be used in the heat release equation.

Although the commenter is technically correct, the definitive 65/65

and the interim 100/100 standards were established based on the use of

a factor of .02323 m2. Furthermore all testing completed to date

has been based on the use of the .02323 factor. Changing the factor to

.0225 at this late date would mean that the 65/65 and 100/100 standards

would have to be changed to 67/67 and 103/103, respectively, in order

to preclude a degradation of the components approved for use in

airplane cabins. This would no doubt cause considerable confusion,

particularly when test results obtained with the .0225 factor are

compared with earlier test results obtained with the original .02323

factor.

The same commenter notes that considerable confusion is created by

the fact that dimensions of the the test apparatus are specified in

U.S. units in some instances and in metric units in others. The FAA

concurs. For clarity, part IV is revised to show dimensions in both

U.S. units and their metric equivalents. Other minor, nonsubstantive

changes are also made to Part IV for clarity.

Section 121.312(a) incorporates the heat release standards of

Sec. 25.853(a-1) by cross reference. Since the latter section applies

only to airplanes with passenger capacities of 20 or more,

Sec. 121.312(a) requires compliance with these heat release standards

only for airplanes with passenger capacities of 20 or more. As one

commenter notes, Sec. 121.312(a) can be misinterpreted to require

compliance for all transport category airplanes regardless of their

passenger capacity. In order to preclude possible confusion in this

regard, both Sec. 121.312(a) and newly adopted Sec. 135.170(b)(1) state

specifically that compliance is required only for airplanes with

passenger capacities of 20 or more.

Another commenter notes that Sec. 121.312(a) (1) through (6) and

the corresponding Sec. 135.170(b)(1) (i) through (vi) are complex and

difficult to understand. The FAA acknowledges that these sections are

very complex. This is due primarily to the fact that there are

differing requirements dependent on such factors as when the airplane

was type certificated, when it was manufactured, when there was a

substantially complete replacement of the cabin interior components,

etc. There is even a distinction between complete replacement of all

cabin interior components in one case and just those components

identified in Sec. 25.853(a-1) in another. The only way in which the

provisions of these sections could be significantly simplified would be

to require compliance for all airplanes at one time. While that would

simplify the regulatory language considerably, it would impose costly

additional burdens on some operators with no commensurate improvement

in safety. Nevertheless, minor nonsubstantive changes have been made

wherever possible to clarify these requirements.

Proposed Sec. 121.312(a)(8) states, in part, that ``* * * galley

carts and galley standard containers that do not meet the heat release

rate testing requirements * * * may be used * * * provided the galley

carts or standard containers were manufactured prior to August 20,

1990.'' One commenter believes that this section should refer to galley

carts and standard containers manufactured prior to a date two years

after the effective date of this amendment.

The FAA concurs that it is inappropriate to specify a date earlier

than the date on which this final rule becomes effective. The FAA does

not, however, agree that an additional two-year compliance time is

necessary. The amendment does not require galley carts and standard

containers manufactured after the specified date to comply. Instead, it

relieves operators of the burden of ensuring that only complying galley

carts and standard containers are loaded on airplanes that are required

to meet the new flammability standards provided the galley carts and

standard containers are manufactured prior to that date. Section

121.312(a)(8) and the corresponding Sec. 135.170(b)(viii) are,

therefore, changed to read, ``* * * provided the galley carts or

standard containers were manufactured prior to March 6, 1995.

One commenter believes that there should be a specific definition

of what constitutes ``substantially complete replacement'' as stated in

Sec. 121.312. The commenter expresses concern that the definition

should allow for the individual replacement of cabin interior

components without the mandatory replacement of all components at the

same time.

``Complete replacement,'' as used in Sec. 121.312 and newly adopted

Sec. 135.170(b), means that all of the affected components in the cabin

are replaced. (As noted above under Background, whether the other

components that are not affected, e.g. seat cushions and flooring, are

replaced is not relevant.) The qualifying word ``substantially'' was

added simply to prevent operators from avoiding compliance by not

replacing a minor, inconsequential cabin component and claiming that

there had not been a ``complete replacement.'' Section 212.312 does,

therefore, permit individual replacement of cabin interior components

without the mandatory replacement of all components at the same time.

This, of course, assumes that the cabin components did not already have

to meet the heat release standards because of the date of manufacture

of the airplane or because they had been completely replaced

previously. It should also be noted that removing components for

refinishing and reinstalling them in the same airplane is considered

``refurbishment,'' not ``replacement.''

Proposed Sec. 135.170(b) states, ``No person may operate a large

airplane unless * * *'' Several commenters note that Part 23 commuter

category airplanes are ``large airplanes,'' as defined by Part 1 of the

FAR, and, as such, would be required to meet the new flammability

standards contained in that section. Another commenter has a similar

concern that proposed

[[Page 6622]]

Sec. 135.170(b) would appear to add substantial requirements for

airplanes type certificated under the provisions of Part 23 and Special

Federal Aviation Regulations (SFAR) No. 41.

Although commuter category airplanes may be large enough to be

``large airplanes'' as defined by Part 1, they are not permitted to

carry more than 19 passengers. Since the flammability standards of

Sec. 135.170(b) apply only to airplanes with more than 19 passengers,

commuter category airplanes would not be required to comply even though

they may be ``large airplanes.'' SFAR No. 41 provides that, contrary

provisions of Part 1 notwithstanding, airplanes certificated under the

provisions of that SFAR are considered to be ``small airplanes'' in

regard to compliance with Part 135. Furthermore they, like commuter

category airplanes, are not permitted to carry more than 19 passengers.

Since neither commuter category airplanes nor those type

certificated under the provisions of SFAR No. 41 are permitted to carry

more than 19 passengers, there is no need to amend Sec. 135.170(b) of

specifically exclude those airplanes. Specifically stating in

Secs. 121.312(a) and 135.170(b)(1) that only airplanes with 20 or more

passengers seats are required to comply, as discussed above, will

preclude confusion in this regard.

One commenter reiterates a belief that the seat cushion

flammability standards of Sec. 25.853(c) are an unnecessary burden for

operators of small transport category airplanes with passenger seating

capacities of fewer than 19 passengers. The commenter is referring in

this regard to the provisions of Sec. 121.312 which were previously

incorporated by cross reference in Sec. 135.169 and now are stated

explicitly as new Sec. 135.170(b)(2). Section 121.312(b) and the new

Sec. 135.170(b)(2), in turn specify that the operator must have seat

cushions that meet the flammability standards of Sec. 25.853(c). That

issue has already been addressed by FAA in earlier rulemaking and is

not related, in any substantive manner, to the present rulemaking.

Another commenter notes an inadvertent error in proposed

Sec. 135.169(a) in that it would incorporate Sec. 121.311 by cross

reference. The intent was to move the no longer needed reference to

Sec. 121.312, not to replace it with Sec. 121.311. Section 135.169(a)

is corrected accordingly.

Regulatory Evaluation

Regulatory Evaluation

Exeuctive Order 12291, dated February 17, 1981, directs Federal

agencies to promulgate new regulations or modify existing regulations

only if potential benefits to society for each regulatory change

outweigh potential costs. This section summarizes the full regulatory

evaluation prepared by the FAA that provides more detailed estimates of

the economic consequences of this regulatory action.

The evaluations prepared for Amendments 25-61 and 121-189, and

Amendments 25-66 and 121-198 remain unchanged by this rule with respect

to costs and benefits, regulatory flexibility determinations, and trade

impact assessment.

None of the amendments in this rule will generate significant costs

or benefits. In part, the rule clarifies the original intent of the

earlier amendments. The changes to the test apparatus and procedures

for determining heat release rate are minor refinements that will

result only in negligible costs and benefits. The amendment to Part 135

is a nonsubstantive change that incorporates existing requirements

explicitly rather than by cross reference. The remaining changes are

editorial or conforming in nature.

Regulatory Flexibility Determination

The Regulatory Flexibility Act of 1989 (RFA) was enacted by

Congress to ensure that small entities are not unnecessarily or

disproportionately burdened by Government regulations. The RFA requires

a Regulatory Flexibility Analysis if a rule has a significant economic

impact, either detrimental or beneficial, on a substantial number of

small entities. FAA Order 2100.14A, Regulatory Flexibility Criteria and

Guidance, established threshold cost values and small entity size

standards for complying with RFA review requirements in FAA rulemaking

actions. The FAA has determined that this rule will not have a

significant economic impact on a substantial number of small entities.

International Trade Impact Analysis

This rule will not have an adverse impact either on the trade

opportunities of U.S. operators or manufacturers of transport category

airplanes doing business abroad, or on foreign operators or aircraft

manufacturers doing business in the United States.

Federalism Implications

The regulations adopted herein will not have substantial direct

effects 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, in

accordance with Executive Order 12612, it is determined that this final

rule will not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

Conclusion: Because the regulations adopted herein are expected to

result only in negligible costs, the FAA has determined that this final

rule is not major as defined in Executive Order 12291. Because this is

an issue that has not prompted a great deal of public concern, this

final rule is not considered to be significant as defined in Department

of Transportation Regulatory Policies and Procedures (44 FR 11034,

February 26, 1979). In addition, since there are no small entities

affected by this rulemaking, it is certified, under the criteria of the

Regulatory Flexibility Act, that this final rule, at promulgation, will

not have a significant economic impact, positive or negative, on a

substantial number of small entities. The regulatory evaluation

prepared for Amendments 25-66 and 121-198 remains applicable and has

been placed on the docket. A copy of this evaluation may be obtained by

contacting the person identified under the caption FOR FURTHER

INFORMATION CONTACT.

List of Subjects

14 CFR Part 25

Aircraft, Air transportation, Aviation safety, Safety.

14 CFR Part 121

Air carriers, Aircraft, Airplanes, Air transportation, Aviation

safety, Common carriers, Flammable materials, Safety, Transportation.

14 CFR Part 135

Air carriers, Aircraft, Airplanes, Air transportation, Aviation

safety, Cargo, Hazardous materials, Mail, Safety, Transportation.

Adption of the Amendment

Accordingly, 14 CFR Parts 25, 121 and 135 of the Federal Aviation

Regulations (FAR) are amended as follows:

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

1. The authority citation for Part 25 is revised to read as

follows:

Authority: 49 U.S.C. 106(g), 1344, 1354(a), 1355, 1421, 1423,

1424, 1425, 1428, 1429, 1430.

2. By revising Sec. 25.853 to read as follows:

[[Page 6623]]

Sec. 25.853 Compartment interiors.

For each compartment occupied by the crew or passengers, the

following apply:

(a) Materials (including finishes or decorative surfaces applied to

the materials) must meet the applicable test criteria prescribed in

Part I of Appendix F of this Part, or other approved equivalent

methods, regardless of the passenger capacity of the airplane.

(b) [Reserved]

(c) In addition to meeting the requirements of paragraph (a) of

this section, seat cushions, except those on flight crewmember seats,

must meet the test requirements of part II of Appendix F of this Part,

or other equivalent methods, regardless of the passenger capacity of

the airplane.

(d) Except as provided in paragraph (e) of this section, the

following interior components of airplanes with passenger capacities of

20 or more must also meet the test requirements of parts IV and V of

Appendix F of this Part, or other approved equivalent method, in

addition to the flammability requirements prescribed in paragraph (a)

of this section:

(1) Interior ceiling and wall panels, other than lighting lenses

and windows;

(2) Partitions, other than transparent panels needed to enhance

cabin safety;

(3) Galley structure, including exposed surfaces of stowed carts

and standard containers and the cavity walls that are exposed when a

full complement of such carts or containers is not carried; and

(4) Large cabinets and cabin stowage compartments, other than

underseat stowage compartments for stowing small items such as

magazines and maps.

(e) The interiors of compartments, such as pilot compartments,

galleys, lavatories, crew rest quarters, cabinets and stowage

compartments, need not meet the standards of paragraph (d) of this

section, provided the interiors of such compartments are isolated from

the main passenger cabin by doors or equivalent means that would

normally be closed during an emergency landing condition.

(f) Smoking is not to be allowed in lavatories. If smoking is to be

allowed in any other compartment occupied by the crew or passengers, an

adequate number of self-contained, removable ashtrays must be provided

for all seated occupants.

(g) Regardless of whether smoking is allowed in any other part of

the airplane, lavatories must have self-contained, removable ashtrays

located conspicuously on or near the entry side of each lavatory door,

except that one ashtray may serve more than one lavatory door if the

ashtray can be seen readily from the cabin side of each lavatory

served.

(h) Each receptacle used for the disposal of flammable waste

material must be fully enclosed, constructed of at least fire resistant

materials, and must contain fires likely to occur in it under normal

use. The capability of the receptacle to contain those fires under all

probable conditions of wear, misalignment, and ventilation expected in

service must be demonstrated by test.

3. By amending part IV of Appendix F to Part 25 by revising

paragraphs (a), (b)(1) through (6), (b)(8), (c)(1), (d) heading and

(d)(1), (d)(3), (e)(1) through (5), (e)(8), (f)(2), and by adding

paragraph (c)(3); transferring Figures 1 through 5 at the end of

Appendix F to the end of part IV of Appendix F and adding a heading

preceding the figures, and by removing Figure 1 of part IV and adding

Figures 1A and 1B in its place to read as follows:

Appendix F to Part 25

* * * * *

Part IV--Test Method to Determine the Heat Release Rate from Cabin

Materials Exposed to Radiant Heat.

(a) Summary of Method. Three or more specimens representing the

completed aircraft component are tested. Each test specimen is injected

into an environmental chamber through which a constant flow of air

passes. The specimen's exposure is determined by a radiant heat source

adjusted to produce, on the specimen, the desired total heat flux of

3.5 W/cm2. The specimen is tested with the exposed surface

vertical. Combustion is initiated by piloted ignition. The combustion

products leaving the chamber are monitored in order to calculate the

release rate of heat.

(b) * * *

(1) This apparatus is shown in Figures 1A and 1B of this part IV.

All exterior surfaces of the apparatus, except the holding chamber,

must be insulated with 1 inch (25 mm) thick, low density, high

temperature, fiberglass board insulation. A gasketed door, through

which the sample injection rod slides, must be used to form an airtight

closure on the specimen hold chamber.

(2) Thermopile. The temperature difference between the air entering

the environmental chamber and that leaving must be monitored by a

thermopile having five hot, and five cold, 24-guage Chromel-Alumel

junctions. The hot junctions must be spaced across the top of the

exhaust stack, .38 inches (10 mm) below the top of the chimney. The

thermocouples must have a .050 .010 inch (1.3

.3mm) diameter, ball-type, welded tip. One thermocouple must be located

in the geometric center, with the other four located 1.18 inch (30 mm)

from the center along the diagonal toward each of the corners (Figure 5

of this part IV). The cold junctions must be located in the pan below

the lower air distribution plate (see paragraph (b)(4) of this part

IV). Thermopile hot junctions must be cleared of soot deposits as

needed to maintain the calibrated sensitivity.

(3) Radiation Source. A radiant heat source incorporating four Type

LL silicon carbide elements, 20 inches (508 mm) long by .63 inch (16

mm) O.D., must be used, as shown in Figures 2A and 2B of this part IV.

The heat source must have a nominal resistance of 1.4 ohms and be

capable of generating a flux up to 100 kW/m\2\. The silicone carbide

elements must be mounted in the stainless steel panel box by inserting

them through .63 inch (16 mm) holes in .03 inch (1 mm) thick ceramic

fiber or calcium-silicate millboard. Locations of the holes in the pads

and stainless steel cover plates are shown in Figure 2B of this part

IV. The truncated diamond-shaped mask of .042.002 inch

(1.07.05mm) stainless steel must be added to provide

uniform heat flux density over the area occupied by the vertical

sample.

(4) Air Distribution System. The air entering the environmental

chamber must be distributed by a .25 inch (6.3 mm) thick aluminum plate

having eight No. 4 drill-holes, located 2 inches (51 mm) from sides on

4 inch (102 mm) centers, mounted at the base of the environmental

chamber. A second plate of 18 guage stainless steel having 120, evenly

spaced, No. 28 drill holes must be mounted 6 inches (152 mm) above the

aluminum plate. A well-regulated air supply is required. The air-supply

manifold at the base of the pyramidal section must have 48, evenly

spaced, No. 26 drill holes located .38 inch (10 mm) from the inner edge

of the manifold, resulting in an airflow split of approximately three

to one within the apparatus.

(5) Exhaust Stack. An exhaust stack, 5.25 x 2.75 inches (133 x 70

mm) in cross section, and 10 inches (254 mm) long, fabricated from 28

guage stainless steel must be mounted on the outlet of the pyramidal

section. A. 1.0 x 3.0 inch (25 x 76 mm) baffle plate of

0.18.002 inch (.50.05 mm) stainless steel must

be centered inside the stack, perpendicular to the air flow, 3 inches

(76 mm) above the base of the stack.

(6) Specimen Holders. (i) The specimen must be tested in a vertical

[[Page 6624]]

orientation. The specimen holder (Figure 3 of this part IV) must

incorporate a frame that touches the specimen (which is wrapped with

aluminum foil as required by paragraph (d)(3) of this Part) along only

the .25 inch (6 mm) perimeter. A ``V'' shaped spring is used to hold

the assembly together. A detachable .50 x .50 x 5.91 inch

(12 x 12 x 150 mm) drip pan and two .020 inch (.5 mm) stainless steel

wires (as shown in Figure 3 of this part IV) must be used for testing

materials prone to melting and dripping. The positioning of the spring

and frame may be changed to accommodate different specimen thicknesses

by inserting the retaining rod in different holes on the specimen

holder.

(ii) Since the radiation shield described in ASTM E-906 is not

used, a guide pin must be added to the injection mechanism. This fits

into a slotted metal plate on the injection mechanism outside of the

holding chamber. It can be used to provide accurate positioning of the

specimen face after injection. The front surface of the specimen must

be 3.9 inches (100 mm) from the closed radiation doors after injection.

(iii) The specimen holder clips onto the mounted bracket (Figure 3

of this part IV). The mounting bracket must be attached to the

injection rod by three screws that pass through a wide-area washer

welded onto a \1/2\-inch (13 mm) nut. The end of the injection rod must

be threaded to screw into the nut, and a .020 inch (5.1 mm) thick wide

area washer must be held between two \1/2\-inch (13 mm) nuts that are

adjusted to tightly cover the hole in the radiation doors through which

the injection rod or calibration calorimeter pass.

(7) * * *

(8) Pilot-Flame Positions. Pilot ignition of the specimen must be

accomplished by simultaneously exposing the specimen to a lower pilot

burner and an upper pilot burner, as described in paragraph (b)(8)(i)

and (b)(8)(ii) or (b)(8)(iii) of this part IV, respectively. Since

intermittent pilot flame extinguishment for more than 3 seconds would

invalidate the test results, a spark ignitor may be installed to ensure

that the lower pilot burner remains lighted.

(i) Lower Pilot Burner. The pilot-flame tubing must be .25 inch

(6.3 mm) O.D., .03 inch (0.8mm) wall, stainless steel tubing. A mixture

of 120 cm3/min. of methane and 850 cm3/min. of air must be

fed to the lower pilot flame burner. The normal position of the end of

the pilot burner tubing is .40 inch (10 mm) from and perpendicular to

the exposed vertical surface of the specimen. The centerline at the

outlet of the burner tubing must intersect the vertical centerline of

the sample at a point .20 inch (5 mm) above the lower exposed edge of

the specimen.

(ii) Standard Three-Hole Upper Burner. The pilot burner must be a

straight length of .25 inch (6.3 mm) O.D., .03 inch (0.8 mm) wall,

stainless steel tubing that is 14 inches (360 mm) long. One end of the

tubing must be closed, and three No. 40 drill holes must be drilled

into the tubing, 2.38 inch (60 mm) apart, for gas ports, all radiating

in the same direction. The first hole must be .19 inch (5 mm) from the

closed end of the tubing. The tube must be positioned .75 inch (19 mm)

above and .75 inch (19 mm) behind the exposed upper edge of the

specimen. The middle hole must be in the vertical plane perpendicular

to the exposed surface of the specimen which passes through its

vertical centerline and must be pointed toward the radiation source.

The gas supplied to the burner must be methane and must be adjusted to

produce flame lengths of 1 inch (25 mm).

(iii) Optional Fourteen-Hole Upper Pilot Burner. This burner may be

used in lieu of the standard three-hole burner described in paragraph

(b)(8)(ii) of this part IV. The pilot burner must be a straight length

of .25 inch (6.3 mm) O.D., .03 inch (0.8 mm) wall, stainless steel

tubing that is 15.75 inches (400 mm) long. One end of the tubing must

be closed, and 14 No. 59 drill holes must be drilled into the tubing,

.50 inch (13 mm) apart, for gas ports, all radiating in the same

direction. The first hole must be .50 inch (13 mm) from the closed end

of the tubing. The tube must be positioned above the specimen holder so

that the holes are placed above the specimen as shown in Figure 1B of

this part IV. The fuel supplied to the burner must be methane mixed

with air in a ratio of approximately 50/50 by volume. The total gas

flow must be adjusted to produce flame lengths of 1 inch (25 mm). When

the gas/air ratio and the flow rate are properly adjusted,

approximately .25 inch (6 mm) of the flame length appears yellow in

color.

(c) * * * (1) Heat Release Rate. A calibration burner, as shown in

Figure 4, must be placed over the end of the lower pilot flame tubing

using a gas tight connection. The flow of gas to the pilot flame must

be at least 99 percent methane and must be accurately metered. Prior to

usage, the wet test meter must be properly leveled and filled with

distilled water to the tip of the internal pointer while no gas is

flowing. Ambient temperature and pressure of the water are based on the

internal wet test meter temperature. A baseline flow rate of

approximately 1 liter/min. must be set and increased to higher preset

flows of 4, 6, 8, 6 and 4 liters/min. Immediately prior to recording

methane flow rates, a flow rate of 8 liters/min. must be used for 2

minutes to precondition the chamber. This is not recorded as part of

calibration. The rate must be determined by using a stopwatch to time a

complete revolution of the wet test meter for both the baseline and

higher flow, with the flow returned to baseline before changing to the

next higher flow. The thermopile baseline voltage must be measured. The

gas flow to the burner must be increased to the higher preset flow and

allowed to burn for 2.0 minutes, and the thermopile voltage must be

measured. The sequence must be repeated until all five values have been

determined. The average of the five values must be used as the

calibration factor. The procedure must be repeated if the percent

relative standard deviation is greater than 5 percent. Calculations are

shown in paragraph (f) of this part IV.

(2) * * *

(3) As noted in paragraph (b)(2) of this part IV, thermopile hot

junctions must be cleared of soot deposits as needed to maintain the

calibrated sensitivity.

(d) Preparation of Test Specimens. (1) The test specimens must be

representative of the aircraft component in regard to materials and

construction methods. The standard size for the test specimens is 5.91

.03 x 5.91 .03 inches (149 1

x 149 1 mm). The thickness of the specimen must be the

same as that of the aircraft component it represents up to a maximum

thickness of 1.75 inches (45 mm). Test specimens representing thicker

components must be 1.75 inches (45 mm).

(2) * * *

(3) Mounting. Each test specimen must be wrapped tightly on all

sides of the specimen, except for the one surface that is exposed with

a single layer of .001 inch (.025 mm) aluminum foil.

(e) Procedure. (1) The power supply to the radiant panel must be

set to produce a radiant flux of 3.5 .05 W/cm2, as

measured at the point the center of the specimen surface will occupy

when positioned for the test. The radiant flux must be measured after

the air flow through the equipment is adjusted to the desired rate.

(2) After the pilot flames are lighted, their position must be

checked as described in paragraph (b)(8) of this part IV.

(3) Air flow through the apparatus must be controlled by a circular

plate orifice located in a 1.5 inch (38.1 mm) I.D. pipe with two

pressure measuring

[[Page 6625]]

points, located 1.5 inches (38 mm) upstream and .75 inches (19 mm)

downstream of the orifice plate. The pipe must be connected to a

manometer set at a pressure differential of 7.87 inches (200 mm) of Hg.

(See Figure 1B of this part IV.) The total air flow to the equipment is

approximately .04 m3/seconds. The stop on the vertical specimen

holder rod must be adjusted so that the exposed surface of the specimen

is positioned 3.9 inches (100 mm) from the entrance when injected into

the environmental chamber.

(4) The specimen must be placed in the hold chamber with the

radiation doors closed. The airtight outer door must be secured, and

the recording devices must be started. The specimen must be retained in

the hold chamber for 60 seconds, plus or minus 10 seconds, before

injection. The thermopile ``zero'' value must be determined during the

last 20 seconds of the hold period. The sample must not be injected

before completion of the ``Zero'' value determination.

(5) When the specimen is to be injected, the radiation doors must

be opened. After the specimen is injected into the environmental

chamber, the radiation doors must be closed behind the specimen.

(6) * * *

(7) * * *

(8) The test duration is five minutes. The lower pilot burner and

the upper pilot burner must remain lighted for the entire duration of

the test, except that there may be intermittent flame extinguishment

for periods that do not exceed 3 seconds. Furthermore, if the optional

three-hole upper burner is used, at least two flamelets must remain

lighted for the entire duration of the test, except that there may be

intermittent flame extinguishment of all three flamelets for periods

that do not exceed 3 seconds.

(9) * * *

(f) * * *

(2) Heat release rates may be calculated from the reading of the

thermopile output voltage at any instant of time as:

[GRAPHIC][TIFF OMITTED]TR02FE95.006

HRR=heat release rate (kw/m\2\)

Vb=baseline voltage (mv)

Vm=measured thermopile voltage (mv)

Kh=calibration factor (kw/mv)

* * * * *

Figures to Part IV of Appendix F

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[GRAPHIC][TIFF OMITTED]TR02FE95.004

[[Page 6627]]

[GRAPHIC][TIFF OMITTED]TR02FE95.005

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[[Page 6628]]

* * * * *

PART 121--CERTIFICATION AND OPERATIONS: DOMESTIC, FLAG, AND

SUPPLEMENTAL AIR CARRIERS AND COMMERCIAL OPERATORS OF LARGE

AIRCRAFT

4. The authority citation for Part 121 continues to read as

follows:

Authority: 49 U.S.C. 1354(a), 1355, 1356, 1357, 1401, 1421-1430,

1472, 1485, and 1502; 49 U.S.C. 106(g); 49 CFR 1.47(a).

5. By amending Sec. 121.312 by revising paragraphs (a)(1) through

(a)(6), adding a new paragraph (a)(8), and revising paragraph (b) to

read as follows:

Sec. 121.312 Materials for compartment interiors.

(a) * * *

(1) Except as provided in paragraph (a)(6) of this section, each

airplane with a passenger capacity of 20 or more and manufactured after

August 19, 1988, but prior to August 20, 1990, must comply with the

heat release rate testing provisions of Sec. 25.853(d) in effect March

6, 1995 (formerly Sec. 25.853(a-1) in effect on August 20, 1986),

except that the total heat release over the first 2 minutes of sample

exposure must not exceed 100 kilowatt minutes per square meter and the

peak heat release rate must not exceed 100 kilowatts per square meter.

(2) Each airplane with a passenger capacity of 20 or more and

manufactured after August 19, 1990, must comply with the heat release

rate and smoke testing provisions of Sec. 25.853(d) in effect March 6,

1995 (formerly Sec. 25.853(a-1) in effect on September 26, 1988).

(3) Except as provided in paragraph (a)(5) or (a)(6) of this

section, each airplane for which the application for type certificate

was filed prior to May 1, 1972, must comply with the provisions of

Sec. 25.853 in effect on April 30, 1972, regardless of the passenger

capacity if there is a substantially complete replacement of the cabin

interior after April 30, 1972.

(4) Except as provided in paragraph (a)(5) or (a)(6) of this

section, each airplane for which the application for type certificate

was filed after May 1, 1972, must comply with the material requirements

under which the airplane was type certificated regardless of the

passenger capacity if there is a substantially complete replacement of

the cabin interior after that date.

(5) Except as provided in paragraph (a)(6) of this section, each

airplane that was type certificated after January 1, 1958, and has a

passenger capacity of 20 or more, must comply with the heat release

rate testing provisions of Sec. 25.853(d) in effect March 6, 1995

(formerly Sec. 25.853(a-1) in effect on August 20, 1986), if there is

substantially complete replacement of the cabin interior components

identified in Sec. 25.853(d) on or after that date, except that the

total heat release over the first 2 minutes of sample exposure shall

not exceed 100 killowatt-minutes per square meter and the peak heat

release rate shall not exceed 100 kilowatts per square meter.

(6) Each airplane that was type certificated after January 1, 1958,

and has a passenger capacity of 20 or more, must comply with the heat

release rate and smoke testing provisions of Sec. 25.853(d) in effect

March 6, 1995 (formerly Sec. 25.853(a-1) in effect on September 26,

1988), if there is a substantially complete replacement of the cabin

interior components identified in Sec. 25.853(d) on or after August 20,

1990.

* * * * *

(8) Contrary provisions of this section notwithstanding, galley

carts and galley standard containers that do not meet the flammability

and smoke emission requirements of Sec. 25.853(d) in effect March 6,

1995 (formerly Sec. 25.853(a-1)) may be used in airplanes that must

meet the requirements of paragraph (a-1), (a)(2), (a)(5) or (a)(6) of

this section, provided the galley carts or standard containers were

manufactured prior to March 6, 1995.

(b) For airplanes type certificated after January 1, 1958, seat

cushions, except those on flight crewmember seats, in any compartment

occupied by crew or passengers must comply with the requirements

pertaining to fire protection of seat cushions in Sec. 25.853(c)

effective on November 26, 1984.

PART 135--AIR TAXI OPERATORS AND COMMERCIAL OPERATORS

6. The authority citation for Part 135 continues to read as

follows:

Authority: 49 U.S.C. 1354(a), 1355(a), 1421-1431, and 1502; 49

U.S.C. 106(g); 49 CFR 1.47(a).

7. By amending Sec. 135.169 by revising paragraph (a) to read as

follows:

Sec. 135.169 Additional airworthiness requirements.

(a) Except for commuter category airplanes, no person may operate a

large airplane unless it meets the additional airworthiness

requirements of Secs. 121.213 through 121.283 and 121.307 of this

chapter.

* * * * *

8. By revising Sec. 135.170 to read as follows:

Sec. 135.170 Materials for compartment interiors.

(a) No person may operate an airplane that conforms to an amended

or supplemental type certificate issued in accordance with SFAR No. 41

for a maximum certificated takeoff weight in excess of 12,500 pounds

unless within one year after issuance of the initial airworthiness

certificate under that SFAR, the airplane meets the compartment

interior requirements set forth in Sec. 25.853(a) in effect March 6,

1995 (formerly Sec. 25.853 (a), (b), (b-1), (b-2), and (b-3) of this

chapter in effect on September 26, 1978).

(b) No person may operate a large airplane unless it meets the

following additional airworthiness requirements:

(1) Except for those materials covered by paragraph (b)(2) of this

section, all materials in each compartment used by the crewmembers or

passengers must meet the requirements of Sec. 25.853 of this chapter in

effect as follows or later amendment thereto:

(i) Except as provided in paragraph (b)(1)(iv) of this section,

each airplane with a passenger capacity of 20 or more and manufactured

after August 19, 1988, but prior to August 20, 1990, must comply with

the heat release rate testing provisions of Sec. 25.853(d) in effect

March 6, 1995 (formerly Sec. 25.853(a-1) in effect on August 20, 1986),

except that the total heat release over the first 2 minutes of sample

exposure rate must not exceed 100 kilowatt minutes per square meter and

the peak heat release rate must not exceed 100 kilowatts per square

meter.

(ii) Each airplane with a passenger capacity of 20 or more and

manufactured after August 19, 1990, must comply with the heat release

rate and smoke testing provisions of Sec. 25.853(d) in effect March 6,

1995 (formerly Sec. 25.83(a-1) in effect on September 26, 1988).

(iii) Except as provided in paragraph (b)(1) (v) or (vi) of this

section, each airplane for which the application for type certificate

was filed prior to May 1, 1972, must comply with the provisions of

Sec. 25.853 in effect on April 30, 1972, regardless of the passenger

capacity, if there is a substantially complete replacement of the cabin

interior after April 30, 1972.

(iv) Except as provided in paragraph (b)(1) (v) or (vi) of this

section, each airplane for which the application for type certificate

was filed after May 1, 1972, must comply with the material requirements

under which the airplane was type certificated regardless of the

passenger capacity if there is a substantially complete replacement of

the cabin interior after that date.

[[Page 6629]]

(v) Except as provided in paragraph (b)(1)(vi) of this section,

each airplane that was type certificated after January 1, 1958, must

comply with the heat release testing provisions of Sec. 25.853(d) in

effect March 6, 1995 (formerly Sec. 25.853(a-1) in effect on August 20,

1986), if there is a substantially complete replacement of the cabin

interior components identified in that paragraph on or after that date,

except that the total heat release over the first 2 minutes of sample

exposure shall not exceed 100 kilowatt-minutes per square meter and the

peak heat release rate shall not exceed 100 kilowatts per square meter.

(vi) Each airplane that was type certificated after January 1,

1958, must comply with the heat release rate and smoke testing

provisions of Sec. 25.853(d) in effect March 6, 1995 (formerly

Sec. 25.853(a-1) in effect on August 20, 1986), if there is a

substantially complete replacement of the cabin interior components

identified in that paragraph after August 19, 1990.

(vii) Contrary provisions of this section notwithstanding, the

Manager of the Transport Airplane Directorate, Aircraft Certification

Service, Federal Aviation Administration, may authorize deviation from

the requirements of paragraph (b)(1)(i), (b)(1)(ii), (b)(1)(v), or

(b)(1)(vi) of this section for specific components of the cabin

interior that do not meet applicable flammability and smoke emission

requirements, if the determination is made that special circumstances

exist that make compliance impractical. Such grants of deviation will

be limited to those airplanes manufactured within 1 year after the

applicable date specified in this section and those airplanes in which

the interior is replaced within 1 year of that date. A request for such

grant of deviation must include a thorough and accurate analysis of

each component subject to Sec. 25.853(d) in effect March 6, 1995

(formerly Sec. 25.853(a-1) in effect on August 20, 1986), the steps

being taken to achieve compliance, and for the few components for which

timely compliance will not be achieved, credible reasons for such

noncompliance.

(viii) Contrary provisions of this section notwithstanding, galley

carts and standard galley containers that do not meet the flammability

and smoke emission requirements of Sec. 25.853(d) in effect March 6,

1995 (formerly Sec. 25.853(a-1) in effect on August 20, 1986), may be

used in airplanes that must meet the requirements of paragraph

(b)(1)(i), (b)(1)(ii), (b)(1)(iv) or (b)(1)(vi) of this section

provided the galley carts or standard containers were manufactured

prior to March 6, 1995.

(2) For airplanes type certificated after January 1, 1958, seat

cushions, except those on flight crewmember seats, in any compartment

occupied by crew or passengers must comply with the requirements

pertaining to fire protection of seat cushions in Sec. 25.853(c)

effective November 26, 1984.

Issued in Washington, D.C., on January 24, 1995.

David R. Hinson,

Administrator.

[FR Doc. 95-2114 Filed 2-1-95; 8:45 am]

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