[Federal Register Volume 61, Number 192 (Wednesday, October 2, 1996)]
[Rules and Regulations]
[Pages 51357-51360]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24885]


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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:

------------------------------------------------------------------------
       Manufacturer              Models and series model airplanes      
------------------------------------------------------------------------
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. 
------------------------------------------------------------------------


[[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]
BILLING CODE 4910-13-U