[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:
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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]
BILLING CODE 4910-13-U