Airworthiness Directives; JanAero Devices B-Series Combustion Heaters, Models B1500, B2030, B3040, and B4050 (formerly owned by Janitrol, C&D, FL Aerospace, and Midland-Ross Corporation)

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-CE-83-AD; Amendment 39-9773; AD 96-20-07]

RIN 2120-AA64

Airworthiness Directives; JanAero Devices B-Series Combustion

Heaters, Models B1500, B2030, B3040, and B4050 (formerly owned by

Janitrol, C&D, FL Aerospace, and Midland-Ross Corporation)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule

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SUMMARY: This amendment supersedes Airworthiness Directive (AD) 82-07-

03, which currently requires repetitively testing (pressure decay) the

combustion tube of JanAero Devices B-Series combustion heaters, Models

B1500, B2030, B3040, and B4050, that are installed on aircraft, and

overhauling any heater that does not pass one of these pressure decay

tests. This action retains the pressure decay test and possible heater

overhaul requirements of AD 82-07-03; and requires repetitive

operational testing of the combustion air pressure switch, and

replacing any combustion pressure switch that does not pass one of

these tests. Two occurrences of failure of the affected heaters

prompted this action. In one case, an explosion resulted and the

baggage compartment door was blown off the airplane. In the other case,

a fire occurred in the baggage compartment while the airplane was in

flight. The actions specified by this AD are intended to prevent an

airplane fire or explosion caused by failure of the heater combustion

tube assembly or combustion air pressure switch.

DATES: Effective November 14, 1996.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of November 14, 1996.

ADDRESSES: Service information that applies to this AD may be obtained

from JanAero Devices, Airport Complex, P.O. Box 273, Fort Deposit,

Alabama 36032; telephone (334) 227-8306; facsimile (334) 227-8596. This

information may also be examined at the Federal Aviation Administration

(FAA), Central Region, Office of the Assistant Chief Counsel,

Attention: Rules Docket 95-CE-83-AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106; or at the Office of the Federal Register,

800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Ms. Linda Haynes, Aerospace Engineer,

FAA, Atlanta Aircraft Certification Office, Campus Building, 1701

Columbia Avenue, suite 2-160, College Park, Georgia 30337-2748;

telephone (404) 305-7377; facsimile (404) 305-7348.

SUPPLEMENTARY INFORMATION:

Events Leading to This AD

A proposal to amend part 39 of the Federal Aviation Regulations (14

CFR part 39) to include an AD that would apply to JanAero Devices B-

Series combustion heaters, Models B1500, B2030, B3040, and B4050, that

are installed on aircraft was published in the Federal Register on

March 15, 1996 (61 FR 10703). The action proposed to supersede AD 82-

07-03 with a new AD that would (1) retain the requirements of

repetitively testing (pressure decay) the combustion tubes of the

heaters, and overhauling any heater that does not pass one of these

pressure decay tests; (2) require repetitive operational testing of the

combustion air pressure switch, and replacing any combustion pressure

switch that does not pass one of these tests; and (3) provide the

option of installing a combustion air pressure

[[Page 51358]]

switch of improved design as terminating action for the repetitive

operational tests. Accomplishment of the proposed actions as specified

in the notice of proposed rulemaking (NPRM) are as follows:

--The pressure decay tests, combustion air pressure switch operational

tests, and possible heater overhaul in accordance with the Overhaul and

Maintenance Manual; and

--The improved design combustion air pressure switch installation in

accordance with JanAero Devices Service Bulletin (SB) # A-102, dated

September 1994.

The proposal was the result of two occurrences of heater failure.

In one case, an explosion resulted and the baggage compartment door was

blown off the airplane. In the other case, a fire occurred in the

baggage compartment while the airplane was in flight.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

Comment Issue No. 1: New Ceramic Coated Combustion Tubes Should Require

Pressure Decay Tests

Four commenters state that the new ceramic coated combustion tubes,

when installed, should still require repetitive pressure decay tests.

These commenters feel that more failures occur in the areas of the

cross-over passages, exhaust or outermost layer, end cap, and the third

layer; the cross-over passage, exhaust layer, and end cap failing

because of cracks or metal fatigue separation, and the third layer

because of cracks caused by heat warping. These commenters further

state that the JanAero ceramic coated tube does not reduce failures in

these areas in that an improved fourth layer and inner cone does not

increase the longevity of a combustion tube.

The FAA does not concur that repetitive pressure decay tests should

be required on the new ceramic coated combustion tubes. The FAA

approved the ceramic combustion tube based on the coating being able to

withstand high temperatures and because testing results of the heater

assembly exceed FAA Technical Standard Order (TSO) requirements. The

FAA believes that, with proper maintenance as specified within the

Janitrol Maintenance and Overhaul Manual, the ceramic coated combustion

tube will operate safely without a repetitive inspection requirement.

No changes to the AD have been made as a result of these comments.

Comment Issue No. 2: New Part Number (P/N) 94E42 Series Combustion Air

Pressure Switch Should Require Repetitive Checks

Four commenters state the ``improved'' JanAero Devices P/N 94E42

switch utilizes the exact same principle as the old switch; that is,

the spring pressure regulates the air pressure required to close the

micro switch. These commenters express the following:

This spring pressure can be adjusted during periodic

maintenance. When power is supplied to the heater, both switches are

closed (spring is in compression). In both of the switch operations,

if the switch fail opens, the heater will not operate. However, if

the switch fails in the closed position, it would go undetected

until the switch is properly inspected. If the defective switch then

remained in service until the combustion air source failed, fuel and

spark in the combustion tube (with no combustion air) could result

in an explosion. Periodic adjustments to the switch is a necessity

because of reduced spring constant. As the spring is compressed over

time, less force is needed to close the circuit.

One of these four commenters went on to express the following:

The new air switch (P/N 94E42) is slightly more tamper-proof,

but the internal construction is similar to the original and subject

to the same failures; that is a microswitch against a diaphragm with

an adjustment screw. The new switch can be field adjusted just like

the old switch, with design the only major difference. The new

switch cannot be adjusted to the point where it closes with no air

pressure on the diaphragm. In time, the spring inside these pressure

switches will sag under load, which will cause a decrease in the

switch setting and result in the switch contacting at an earlier

point than when new.

The FAA does not concur. The new air switch, P/N 94E42, is forward

spring biased; that is, any extreme or over adjustments will cause the

device to fail in a normal open position, thereby preventing any fuel

introduction or ignition with an improperly adjusted switch. The

adjusting screw housing is potted after factory adjustment to prevent

accidental movement during field readjustment. The intent of this AD is

to prevent failure of the switch. The FAA believes that, with proper

maintenance as called for in the Janitrol Maintenance and Overhaul

Manual, the combustion air pressure switch will not fail and will

operate safely. No changes to the AD have been made as a result of

these comments.

Comment Issue No. 3: Change The AD Applicability to Include All

Combustion Heaters

One commenter suggests the AD cover all combustion heaters because

of aging and lack of maintenance or periodic checks. Another commenter

states that, since all combustion heaters are subject to the same

operation and conditions, all have the same failure capacity and

subsequent failure results.

The FAA does not concur. AD actions provide corrective action for

products where an unsafe condition has been identified, either through

documented service problems or scientific testing, knowledge, etc. AD's

are not used to mandate routine maintenance, in this case as outlined

in the Janitrol Maintenance and Overhaul Manual. The FAA has no data

for which to issue an AD against all combustion heaters; only for those

that are affected by this action. The FAA will consider future

rulemaking action against other combustion heaters if data indicates

that an unsafe condition exists as a result of conditions other than

aircraft owners/operators not accomplishing routine maintenance

actions. No changes have been made to the AD as a result of these

comments.

Comment Issue No. 4: Change the Applicability of the AD

One commenter suggests that the FAA clarify the AD by changing the

Applicability section of the AD to read as follows:

Applicability: B-Series Combustion Heaters, Models B1500, B2030,

B3040, and B4050, marked as meeting the standards of TSO-320 and are

installed on, but not limited to, the following aircraft (all serial

numbers), certificated in any category:

Note: Superseding new B-Series combustion heaters, Models 2500,

B3500, and B4500 incorporate a ceramic coated combustion tube and

new combustion air pressure switch, P/N 94E42, are exempt from the

AD (see JanAero Devices Service Letter # A-101 for superseding

data).

The FAA partially concurs. The only difference that the FAA has

found between the wording currently in the proposal and what the

commenter has suggested is the addition of the note to clarify that

certain combustion heater models incorporate the P/N 94E42 combustion

tube and air pressure switch and are exempt from the AD. The FAA will

add a similar note to the AD for clarification purposes.

Comment Issue No. 5: Assure the Correct Service Bulletin Is Called Out

in the AD

One commenter states that in the preamble to the NPRM, reference to

[[Page 51359]]

JanAero Devices SB # A-102 was incorrectly referenced as JanAero SB NZ

A-102. The commenter requests that all subsequent references to the

service bulletin accurately reflect the title.

The FAA concurs that all reference to the service bulletin should

reflect the correct title, and will assure that reference is correct in

the final rule. In addition, JanAero Devices has superseded JanAero SB

#A- 102 with JanAero SB # A-103, dated September 1995. All reference to

JanAero Devices SB # A-102 will be changed to JanAero Devices SB # A-

103.

Comment Issue No. 6: Change the Wording of the AD for Clarification

One commenter requests that the FAA clarify the AD by combining and

rewording paragraphs (a)(1) and (a)(2) of the AD to read as follows:

If any heater does not pass any of the repetitive combustion

tube pressure decay tests required by this AD, prior to further

flight, overhaul the heater and replace the combustion tube with a

serviceable tube or replace the heater assembly and revert to the

initial 500 hours accumulated time-in-service (TIS) to begin

repetitive testing per this AD.

Note: Replacement with a new or rebuilt superseding Heater Model

(B2500, B3500, or B4500) that incorporates a ceramic coated

combustion tube exempts the heater from this AD.

The FAA does not concur. The only difference that the FAA has found

between the wording currently in the proposal and what the commenter

has suggested is the addition of the note to clarify that certain

combustion heater models incorporate the P/N 94E42 combustion tube and

air pressure switch and are exempt from the AD. However, this note has

already been added after the Applicability section of the AD so the

only thing this note would add is duplication. No changes have been

made to the AD as a result of this comment.

The FAA's Determination

After careful review of all available information related to the

subject presented above, the FAA has determined that air safety and the

public interest require the adoption of the rule as proposed except for

the addition of the clarification note, the change in service

information, and minor editorial corrections. The FAA has determined

that the addition, change, and minor corrections will not change the

meaning of the AD and will not add any additional burden upon the

public than was already proposed.

Compliance Times of This Action

The compliance times of this AD are presented in both hours time-

in-service and calendar time (with the prevalent one being whichever

occurs first). The reason for the dual compliance time is that the

affected combustion heaters are susceptible to corrosion (occurs

regardless of whether the airplane is in flight or on the ground) as

well as being affected by thermodynamic and pressure cycles accumulated

through regular airplane usage.

Cost Impact

The FAA estimates that 25,700 airplanes in the U.S. registry will

be affected by this AD, that it will take approximately 1 workhour per

aircraft to accomplish the required initial inspection, and that the

average labor rate is approximately $60 an hour. Based on these

figures, the total cost impact of the AD on U.S. operators is estimated

to be $1,542,000 or $60 per aircraft. This figure does not take into

account the number of repetitive inspections each aircraft owner/

operator will incur over the life of the aircraft, or the number of

aircraft that have an improved design combustion air pressure switch

installed. The FAA has no way of determining the number of repetitive

inspection each owner/operator would incur over the life of the

airplane. The FAA is not aware of any affected airplane owner/operator

that has incorporated the new design parts as of the issuance of this

AD.

AD 82-03-07 currently requires the pressure decay tests on aircraft

with the affected heaters installed. This action maintains these

inspections; so the only cost impact of the required action is that of

the combustion air pressure switch operational tests.

Regulatory Impact

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 does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) will not have a

significant economic impact, positive or negative, on a substantial

number of small entities under the criteria of the Regulatory

Flexibility Act. A copy of the final evaluation prepared for this

action is contained in the Rules Docket. A copy of it may be obtained

by contacting the Rules Docket at the location provided under the

caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends part 39 of

the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing Airworthiness Directive

(AD) 82-07-03, Amendment 39-4354, and by adding a new AD to read as

follows:

96-20-07 Janaero Devices (formerly Janitrol, C&D, FL Aerospace, and

Midland-Ross Corporation): Amendment 39-9773; Docket No. 95-CE-83-

AD; Supersedes AD 82-07-03, Amendment 39-4354.

Applicability: B-Series combustion heaters, Models B1500, B2030,

B3040, and B4050, marked as meeting the standards of TSO-C20, that

do not incorporate a ceramic combustion tube and a part number (P/N)

94E42 combustion air pressure switch, and are installed on, but not

limited to, the following aircraft (all serial numbers),

certificated in any category:

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Manufacturer Models and series model airplanes

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Beech.................... Models 95-B55 Series, 58, 58TC, 58P, 60, A60,

and 76.

Canadair................. Models CL-215, CL-215T, and CLT-415.

Cessna................... Models 208, 303, 310F, 310G, 310H, 310I,

310J, 310K, 310L, 310M, 310N, 310O, 310P,

320C, 320D, 320E, 320F, 337 series, 340,

340A, 414, 414A, 421, 421A, 421B, and 421C.

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[[Page 51360]]

Note 1: B-Series combustion heaters, Models 2500, B3500, and

B4500, incorporate a ceramic-coated combustion tube and new

combustion air pressure switch, P/N 94E42. This AD does not apply to

this configuration.

Note 2: This AD applies to each aircraft identified in the

preceding applicability provision, regardless of whether it has been

modified, altered, or repaired in the area subject to the

requirements of this AD. For airplanes that have been modified,

altered, or repaired so that the performance of the requirements of

this AD is affected, the owner/operator must request approval for an

alternative method of compliance in accordance with paragraph (d) of

this AD. The request should include an assessment of the effect of

the modification, alteration, or repair on the unsafe condition

addressed by this AD; and, if the unsafe condition has not been

eliminated, the request should include specific proposed actions to

address it.

Compliance: Required as follows, as applicable:

--For aircraft with 450 or more heater hours time-in-service (TIS)

(see Note 3 for information on how to determine heater hours TIS)

accumulated on an installed heater since the last overhaul or new

installation, within the next 50 heater hours TIS or 12 calendar

months after the effective date of this AD, whichever occurs first,

unless already accomplished, and thereafter at intervals not to

exceed 100 heater hours TIS or 24 calendar months, whichever occurs

first;

--For aircraft with less than 450 heater hours TIS accumulated on an

installed heater since the last overhaul or new installation, upon

accumulating 500 heater hours TIS on the new or overhauled heater or

within the next 12 calendar months after the effective date of this

AD, whichever occurs first, unless already accomplished, and

thereafter at intervals not to exceed 100 heater hours TIS or 24

calendar months, whichever occurs first; and

--Upon installing one of the affected heaters, and thereafter at

intervals not to exceed 100 heater hours TIS or 24 calendar months,

whichever occurs first.

Note 3: A heater hour meter may be used to determine heater

hours TIS. Also, aircraft hours TIS may be divided in half to come

up with heater hours TIS.

To prevent an airplane fire or explosion caused by failure of

the heater combustion tube assembly or combustion air pressure

switch, accomplish the following:

(a) Test (pressure decay test) the combustion tube of the heater

and conduct an operational test of the combustion air pressure

switch in accordance with Section III, paragraph 3.3.1 through

3.3.13 (pressure decay test) and Section IV, paragraph 4.9c

(operational switch test), of the Janitrol Maintenance and Overhaul

Manual, part number (P/N) 24E25-1, dated October 1981.

(1) If any heater does not pass any of the repetitive combustion

tube pressure decay tests required by this AD, prior to further

flight, overhaul the heater and replace the combustion tube with a

serviceable tube or replace the heater assembly. If the new or

rebuilt heater assembly incorporates a ceramic combustion tube, then

the repetitive pressure decay tests are no longer required.

(2) If any heater does not pass any of the repetitive combustion

air pressure switch operational tests required by this AD, prior to

further flight, replace the switch with one of the same design or

with a P/N 94E42 switch in accordance with JanAero Devices Service

Bulletin # A-103, dated September 1995. Replacing the combustion air

pressure switch with a P/N 94E42 switch eliminates the repetitive

operational testing requirement of this AD.

(b) As an alternative method of compliance to the requirements

of this AD, the heater may be disabled by accomplishing the

following:

(1) Cap the fuel supply line;

(2) Disconnect the electrical power and ensure that the

connections are properly secured to reduce the possibility of

electrical spark or structural damage;

(3) Inspect and test to ensure that the cabin heater system is

disabled;

(4) Ensure that no other aircraft system is affected by this

action;

(5) Ensure there are no fuel leaks; and

(6) Fabricate a placard with the words: ``System Inoperative''.

Install this placard at the heater control valve within the pilot's

clear view.

(c) Special flight permits may be issued in accordance with

sections 21.197 and 21.199 of the Federal Aviation Regulations (14

CFR 21.197 and 21.199) to operate the airplane to a location where

the requirements of this AD can be accomplished.

(d) An alternative method of compliance or adjustment of the

compliance time that provides an equivalent level of safety may be

approved by the Manager, Atlanta Aircraft Certification Office

(ACO), Campus Building, 1701 Columbia Avenue, suite 2-160, College

Park, Georgia 30337-2748. The request shall be forwarded through an

appropriate FAA Maintenance Inspector, who may add comments and then

send it to the Manager, Atlanta ACO. Alternative methods of

compliance for the combustion tube repetitive inspections required

by this AD that are approved in accordance with AD 82-07-03

(superseded by this action) are approved as alternative methods of

compliance with the applicable portion of paragraph (a) of this AD.

Note 4: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Atlanta ACO.

(e) The possible switch replacement required by this AD shall be

done in accordance with JanAero Devices Service Bulletin # A-103,

dated September 1995. This incorporation by reference was approved

by the Director of the Federal Register in accordance with 5 U.S.C.

552(a) and 1 CFR part 51. Copies may be obtained from JanAero

Devices, Airport Complex, P.O. Box 273, Fort Deposit, Alabama 36032.

Copies may be inspected at the FAA, Central Region, Office of the

Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City,

Missouri, or at the Office of the Federal Register, 800 North

Capitol Street, NW., suite 700, Washington, DC.

(f) This amendment (39-9773) supersedes AD 82-07-03, Amendment

39-4354.

(g) This amendment (39-9773) becomes effective on November 14,

1996.

Issued in Kansas City, Missouri, on September 20, 1996.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft Certification Service.

[FR Doc. 96-24885 Filed 10-1-96; 8:45 am]

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