AD Amdt-39-10399

[Federal Register Volume 63, Number 53 (Thursday, March 19, 1998)]
[Rules and Regulations]
[Pages 13335-13337]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 98-6759]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-200-AD; Amendment 39-10399; AD 98-06-21]
RIN 2120-AA64


Airworthiness Directives; British Aerospace BAe Model ATP 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain British Aerospace BAe Model ATP airplanes, that 
requires repetitive inspections to detect uneven wear of the heat pack 
of the main landing gear (MLG) brake unit; measurement and setting of 
the wear remaining length (WRL) of the wear indicator pin (WIP); and 
replacement of the brake heat pack unit with a serviceable unit, if 
necessary. This amendment is prompted by issuance of mandatory 
continuing airworthiness information by a foreign civil airworthiness 
authority. The actions specified by this AD are intended to detect 
uneven wear of the brake heat pack unit and prevent failure of the 
pressure stator of the MLG brake unit, which could result in reduced 
braking efficiency and consequent longer stopping distances upon 
landing.

DATES: Effective April 23, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 23, 1998.

ADDRESSES: The service information referenced in this AD may be 
obtained from AI(R) American Support, Inc., 13850 Mclearen Road, 
Herndon, Virginia 20171. This information may be examined at the 
Federal Aviation Administration (FAA), Transport Airplane Directorate, 
Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 227-1149.

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 certain British Aerospace BAe 
Model ATP airplanes was published in the Federal Register on November 
26, 1997 (62 FR 63042). That action proposed to require repetitive 
inspections to detect uneven wear of the heat pack of the main landing 
gear (MLG) brake unit; measurement and setting of the wear remaining 
length (WRL) of the wear indicator pin (WIP); and replacement of the 
brake heat pack unit with a serviceable unit, if necessary.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposed rule.
    One commenter requests that the proposal be withdrawn because no 
instances of uneven brake wear of the brake heat pack have occurred. 
The commenter states that its airplanes have the lowest brake life of 
the worldwide fleet of the affected airplanes, the operating 
environment is different from all other operators of these airplanes 
models, and that, during maintenance, the whole brake assembly (rather 
than just the brake heat packs) are changed.
    The FAA does not concur with the commenter's request to withdraw 
the proposal. As explained in the preamble of the proposal, this action 
was prompted by reports indicating that the heat pack unit of the main 
landing gear brake unit exhibited uneven wear at the pressure stator/
first rotor interface in some instances, which resulted in a small 
number of failures of the pressure stator. In light of these reports, 
the FAA identified the existence of an unsafe condition that is likely 
to exist or develop in the affected airplanes. As a result, the FAA is 
issuing this AD to eliminate that unsafe condition by requiring 
repetitive inspections to detect uneven wear of the heat pack; 
measurement and setting of the wear remaining length of the wear 
indicator pin; and replacement of the brake heat pack unit with a 
serviceable unit, if necessary. The AD is the appropriate vehicle for 
mandating such actions.

Removal of Service Bulletin Citation

    The FAA has revised this final rule to move references to Jetstream 
Service Bulletin ATP/J61-32-71, dated May 23, 1996, from paragraphs (a) 
and (b) of this AD to a new Note 2. This new note indicates that 
accomplishment of the actions required by those paragraphs prior to the 
effective date of this AD in accordance with the original issue of the

[[Page 13336]]

service bulletin is considered acceptable for compliance with those 
actions. The FAA has determined that the actions recommended by the 
original issue of the service bulletin are essentially identical to 
those specified in Revision 1. Therefore, the FAA finds that it is 
appropriate to cite the latest revision of the service bulletin and 
reference the original issue in a note.

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 as proposed.

Cost Impact

    The FAA estimates that 10 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 5 work hours per 
airplane to accomplish the required actions, and that the average labor 
rate is $60 per work hour. Based on these figures, the cost impact of 
the AD on U.S. operators is estimated to be $3,000, or $300 per 
airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted.

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 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:

98-06-21  British Aerospace Regional Aircraft [Formerly Jetstream 
Aircraft Limited; British Aerospace (Commercial Aircraft) Limited]: 
Amendment 39-10399. Docket 96-NM-200-AD.

    Applicability: BAe Model ATP airplanes having constructors 
numbers 2002 through 2067 inclusive, certificated in any category.

    Note 1: This AD applies to each airplane 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 (c) 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 indicated, unless accomplished 
previously.
    To detect uneven wear of the brake heat pack unit and prevent 
failure of the pressure stator of the main landing gear (MLG) brake 
unit, which could result in reduced braking efficiency and 
consequent longer stopping distances upon landing, accomplish the 
following:

    Note 2: Accomplishment of the actions required by paragraphs (a) 
and (b) of this AD prior to the effective date of this AD in 
accordance with Jetstream Service Bulletin ATP/J61-32-71, dated May 
23, 1996, is considered acceptable for compliance with the 
applicable actions specified in this amendment.

    (a) Within 300 hours time-in-service (TIS) after the effective 
date of this AD: Perform an inspection of the brake units of the 
left and right MLG to detect uneven wear at the pressure stator/
first rotor interface, measure the wear remaining length (WRL) of 
the wear indicator pin (WIP), and accomplish the action specified in 
paragraph (a)(1) or (a)(2) of this AD, as applicable; in accordance 
with Jetstream Service Bulletin ATP/J61-32-71, Revision 1, dated 
June 18, 1996.

    Note 3: Jetstream Service Bulletin ATP/J61-32-71, dated May 23, 
1996, and Revision 1, dated June 18, 1996, reference Dunlop Service 
Bulletin AHA1612/AHA2004-32-1122, dated April 16, 1996, as an 
additional source of service information for procedures to inspect 
the brakes, measure the WRL of the WIP, and set the corrected length 
of the pin.

    (1) If the WRL of the WIP is greater than or equal to 0.5 
inches: Repeat the action required in paragraph (a) of this AD 
thereafter at intervals not to exceed 300 hours TIS.
    (2) If the WRL of the WIP is less than 0.5 inches: Prior to 
further flight, measure the thickness of the pressure stator and 
accomplish the action specified in paragraph (a)(2)(i) or (a)(2)(ii) 
of this AD, as applicable; and repeat the action required in 
paragraph (a) of this AD thereafter at intervals not to exceed 300 
hours TIS.
    (i) If the pressure stator is less than or equal to 0.31 inches 
thick: Replace the heat pack of the MLG brake unit with a 
serviceable unit and set the WRL of the WIP to indicate the 
corrected WRL measurement.
    (ii) If the pressure stator exceeds 0.31 inches thick: Set the 
WRL of the WIP to indicate the corrected WRL measurement.
    (b) If, during any inspection required by this AD, the WRL of 
the WIP on any brake unit shows that the wear status of the brake 
heat pack is not within the acceptable limits specified in Jetstream 
Service Bulletin ATP/J61-32-71, dated May 23, 1996, or Revision 1, 
dated June 18, 1996: Prior to further flight, replace the brake heat 
pack unit with a serviceable unit in accordance with Jetstream 
Service Bulletin ATP/J61-32-71, Revision 1, dated June 18, 1996; and 
repeat the action required in paragraph (a) of this AD thereafter at 
intervals not to exceed 300 hours TIS.
    (c) An alternative method of compliance or adjustment of the 
initial compliance time that provides an acceptable level of safety 
may be used if approved by the Manager, International Branch, ANM-
116, FAA, Transport Airplane Directorate. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add additional comments, and then send it to the 
Manager, International Branch, ANM-116.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (d) 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.
    (e) The actions shall be done in accordance with Jetstream 
Service Bulletin ATP/J61-32-71, Revision 1, dated April 16, 1996, 
which contains the specified effective pages:

[[Page 13337]]



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        Revision level page number                 Shown on page                    Date shown on page          
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1, 3......................................  1..........................  June 18, 1996.                         
2, 4, 5...................................  Original...................  May 23, 1996.                          
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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 AI(R) American Support, Inc., 13850 
Mclearen Road, Herndon, Virginia 20171. Copies may be inspected at 
the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.

    Note 5: The subject of this AD is addressed in British 
airworthiness directive 002-05-96.

    (f) This amendment becomes effective on April 23, 1998.

    Issued in Renton, Washington, on March 10, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-6759 Filed 3-18-98; 8:45 am]
BILLING CODE 4910-13-U