[Federal Register Volume 65, Number 46 (Wednesday, March 8, 2000)]
[Rules and Regulations]
[Pages 12085-12088]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-5009]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-34-AD; Amendment 39-11607; AD 2000-04-24]
RIN 2120-AA64


Airworthiness Directives; Honeywell International (formerly 
AlliedSignal Inc.) 36-300(A), 36-280(B), and 36-280(D) Series Auxiliary 
Power Units

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Honeywell International (formerly AlliedSignal Inc.) 36-
300(A), 36-280(B), and 36-280(D) series Auxiliary Power Units (APUs). 
This amendment requires installation of an external load compressor 
containment shield, or installation of a load compressor impeller with 
lower stress concentrations. This amendment is prompted by reports of 
load compressor impeller failures. The actions specified by this AD are 
intended to prevent an

[[Page 12086]]

uncontained APU failure and damage to the airplane.

DATES: Effective May 8, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 8, 2000.

ADDRESSES: The service information referenced in this AD may be 
obtained from Honeywell International, Inc., Attn: Data Distribution, 
M/S 64-3/2101-201, PO Box 29003, Phoenix, AZ 85038-9003; telephone 602-
365-2493, fax 602-365-5577. This information may be examined at the 
Federal Aviation Administration (FAA), New England Region, Office of 
the Regional Counsel, 12 New England Executive Park, Burlington, MA; or 
at the Office of the Federal Register, 800 North Capitol Street, NW, 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Roger Pesuit, Aerospace Engineer, Los 
Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone 
562-627-5251, fax 562-627-5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to Honeywell International (formerly 
AlliedSignal Inc.) 36-300(A), 36-280(B), and 36-280(D) series Auxiliary 
Power Units (APUs) was published in the Federal Register on September 
8, 1999 (64 FR 48723). That action proposed to require installation of 
an external load compressor containment shield at the next shop visit, 
or 6 months after the effective date of this AD, whichever occurs 
first. An additional compliance option would be installation of a load 
compressor impeller, part number (P/N) 3822270-5, to extend cyclic 
service life to 26,000 cycles-since-new (CSN) before mandatory 
installation of the containment shield. Operators cannot operate with a 
load compressor installed, P/N 3822270-5, past 26,000 CSN unless they 
have installed an external containment shield. That action was prompted 
by three incidents where the load compressor impellers separated, 
resulting in uncontained APU failures and debris entering the APU 
compartment. That condition, if not corrected, could result in an 
uncontained APU failure and damage to the airplane.

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Expand the Applicability

    One commenter requests to add load compressor impeller, P/Ns 
3822270-1 and 3822270-3, to the applicability in addition to P/Ns 
3822270-4 and 3822270-5. Both load compressor impellers, P/Ns 3822270-1 
and 3822270-3, are affected by the same damper ring groove condition as 
the impellers already affected by the proposal. The FAA does not 
concur. While impellers, P/Ns 3822270-1 and 3822270-3, are subject to 
the same failure mode as P/N 3822270-4 load compressor impellers 
affected by this AD, all load compressor impellers, P/Ns 3822270-1 and 
3822270-3, were required to be reworked to the P/N 3822270-4 
configuration by AD 92-21-05. The FAA has added a note referring to the 
requirement of AD 92-21-05 to remind operators that the old load 
compressor impeller designs shall no longer be used in service.

Clarification of Cyclic Determination

    One commenter requests clarification in how to determine the number 
of cycles on load compressor impellers in service. The commenter wishes 
to use its existing system for determining the number of cycles on the 
load compressor impellers instead of the method described by the 
manufacturer in its applicable service bulletin (SB). The FAA concurs. 
Since the AD does not require the use of the SB's cycle counting 
methodology, operators may use their own approved system to calculate 
cycles. A note has been added following paragraph (b) to address 
acceptable methods of determining part cycles.

Subsequent Serial Number (S/N) Parts

    The same commenter notes that the AlliedSignal Inc. SB does not 
list all P/N 3822270-5 impellers in service. The FAA concurs. When the 
SB was written all subsequent S/N parts that would be produced could 
not have been anticipated. Since all S/Ns are affected, the 
applicability paragraph in this final rule has been rewritten to 
clarify that this AD applies to APUs with P/N 3822270-4 or -5 impellers 
installed. The applicability paragraph of the AD takes precedence over 
the AlliedSignal Inc. SB's list of S/Ns. For parts not listed 
specifically in the SB, the SB provides a procedure to obtain the 
required information.

Clarification of Compliance Times

    The same commenter requests clarification on the compliance times 
for load compressor impellers, P/N 3822270-5. The commenter notes there 
appears to be contradictory requirements between paragraphs (b) and (c) 
of the proposal. Paragraph (b) of the proposal allows operating 
impellers, P/N 3822270-5, above 26,000 CSN, for six months after the 
effective date of the AD. Paragraph (c) requires that an external 
containment shield be in place before operating the APU past 26,000 
CSN. The FAA concurs. Paragraph (c) of this final rule has been 
modified to clarify that the calendar time requirement applies along 
with the cycle time limit.

Can an Operator Remove the Containment Shield With a Lower Time 
Impeller Installed?

    The same commenter requests clarification on the possibility of 
removal of the external load compressor containment shield when a lower 
time impeller is installed. The same commenter also asks why APUs 
containing P/N 3822270-5 load compressor impellers are not managed to a 
26,000 CSN life limit. The commenter states that the proposal does not 
specifically prohibit removing the external containment shield when P/N 
3822270-5 load compressor impellers with less than 26,000 CSN are 
installed. Operating to a 26,000 CSN limit would be preferred to 
incorporation of an external load compressor containment shield because 
it would avoid the potential for APU damage in the event that an 
impeller does fail. The FAA concurs in part. The commenter may choose, 
within the requirements of this final rule, to operate with low time P/
N 3822270-5 impellers installed without external load compressor 
containment shields, or with P/N 3822270-5 impellers with more than 
26,000 CSN and external load compressor containment shields installed.

Extend Calendar End-Date

    One commenter requests an extension from six months to two years 
for the calendar end-date for APUs containing P/N 3822270-5 load 
compressor impellers. The commenter believes that there is inadequate 
information available to accurately determine the actual number of 
cycles on load compressor impellers. The commenter therefore believes 
that the only practical means of complying with the AD is the calendar 
method. Extension from six months to two years would allow for orderly 
scheduling of the installation of the containment shield with scheduled 
maintenance intervals. The FAA concurs in part. Although detailed load

[[Page 12087]]

compressor impeller cycle times are not known for all APUs, the 
AlliedSignal SB procedure provides a method for assigning cyclic times 
which are reasonable based upon review of APU operating history. The 
FAA has determined that for impellers, P/N 3822270-5, an extension of 
the calendar end-date from six months to one year would be reasonable 
to allow incorporation of the containment shield with scheduled 
maintenance intervals while maintaining an adequate safety level.

APU Model Numbers

    The APUs affected by this AD are sometimes referred to as GTCP36-
300(A), GTCP36-280(B) and GTCP36-280(D) series APUs. The presence or 
absence of the letters ``GTCP'' preceding the model number does not 
affect the applicability of this AD on those APUs. The FAA has added a 
note to clarify that the AD applies to the specified APU series whether 
or not the letters ``GTCP'' appear on the dataplate.

New Company Name

    Since publication of the proposal, AlliedSignal has adopted the 
Honeywell International, Inc. name. This final rule has been altered 
accordingly to refer to the new company name with AlliedSignal Inc. 
listed as the former company name.

Concur With Proposal

    One commenter concurs with the rule as proposed.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Economic Analysis

    There are approximately 1,044 APUs of the affected design in the 
worldwide fleet. The FAA estimates that 465 APUs installed on airplanes 
of US registry will be affected by this AD, that it will take 
approximately 6 work hours per Model 36-300(A) APU (85 units) to 
accomplish the proposed actions, and 8 work hours per Model 36-280(D) 
APU (380 units), and that the average labor rate is $60 per work hour. 
Required parts will cost approximately $3,103 per APU. Fifteen 
installations on domestic Boeing 737 aircraft (Model 36-280(B)) will 
require a tube assembly kit, which would cost approximately $1,042. The 
manufacturer has informed the FAA that it may offset some of these 
costs thereby lowering the total cost to operators. Based on these 
figures, the total cost impact of the AD on US operators is estimated 
to be $1,725,270.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from 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 adding the following new 
airworthiness directive:

2000-04-24  Honeywell International (formerly Allied Signal Inc.):
    Amendment 39-11607. Docket 99-NE-34-AD.

    Applicability: Honeywell International (formerly AlliedSignal 
Inc.) 36-300(A), 36-280(B), and 36-280(D) series Auxiliary Power 
Units (APUs), with load compressor impellers, part numbers (P/Ns) 
3822270-4, or 3822270-5, installed. These APUs are installed on but 
not limited to Airbus Industrie A319, A320, and A321 series; Boeing 
737-300, -400, -500 series; and McDonnell Douglas MD-80 series 
airplanes.


    Note 1: This airworthiness directive (AD) applies to each APU 
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 APUs 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 (f) 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.


    Note 2: The presence or absence of the letters ``GTCP'' 
preceding the model series does not affect the applicability of this 
AD to the specified model APUs.


    Note 3: AD 92-21-05 requires that all APUs with load compressor 
impellers, P/Ns 3822270-1 or 3822270-3, be reworked to 
the -4 configuration.


    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an uncontained APU failure and damage to the 
airplane, accomplish the following:

Load Compressor Impellers, P/N 3822270-4

    (a) For APUs with load compressor impellers, P/N 3822270-4, at 
the next shop visit, or within 6 months after the effective date of 
this AD, whichever occurs first, accomplish either of the following:
    (1) Install an external load compressor containment shield in 
accordance with AlliedSignal Inc. Service Bulletins (SBs) No. 
GTCP36-49-7471, dated April 20, 1999, GTCP36-49-7472, dated March 
31, 1999, or GTCP36-49-7473, dated March 31, 1999, as applicable; or
    (2) Install load compressor impeller, P/N 3822270-5.

Load Compressor Impellers, P/N 3822270-5

    (b) For APUs with load compressor impellers, P/N 3822270-5, 
install an external load compressor containment shield within one 
year after the effective date of this AD, or prior to the impeller 
exceeding 26,000 cycles-since-new (CSN), whichever occurs later, in 
accordance with AlliedSignal Inc. SBs No. GTCP36-49-7471, dated 
April 20, 1999, GTCP36-49-7472, dated March 31, 1999, or GTCP36-49-
7473, dated March 31, 1999, as applicable.


    Note 4: Operators may use their own FAA-approved tracking system 
for determining load compressor impeller cyclic count in lieu of the 
procedure described in the AlliedSignal Inc. SBs referenced in this 
AD.


[[Page 12088]]



Cyclic Limit without External Containment Shield

    (c) Following one year after the effective date of this AD, 
operators cannot operate with a load compressor, P/N 3822270-5, 
installed, past 26,000 cycles unless they have installed an external 
load compressor containment shield.

Definition

    (d) For the purpose of this AD, a shop visit is defined as when 
the APU is inducted into a shop for any reason.

Alternative Methods of Compliance

    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Los Angeles Aircraft Certification 
Office. Operators shall submit their request through an appropriate 
FAA Principal Maintenance Inspector, who may add comments and then 
send it to the Manager, Los Angeles Aircraft Certification Office.


    Note 5: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Los Angeles Aircraft Certification 
Office.

Ferry Flights

    (f) 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.

Incorporation by Reference

    (g) The actions required by this AD shall be done in accordance 
with the following AlliedSignal Inc. SBs: GTCP36-49-7471, dated 
April 20, 1999, GTCP36-49-7472, dated March 31, 1999, and GTCP36-49-
7473, dated March 31, 1999. 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 
Honeywell International, Inc., Attn: Data Distribution, M/S 64-3/
2101-201, PO Box 29003, Phoenix, AZ 85038-9003; telephone 602-365-
2493, fax 602-365-5577. Copies may be inspected at the FAA, New 
England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street, NW, suite 700, Washington, DC.
    (h) This amendment becomes effective on May 8, 2000.


    Issued in Burlington, Massachusetts, on February 25, 2000.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 00-5009 Filed 3-7-00; 8:45 am]
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