[Federal Register Volume 62, Number 228 (Wednesday, November 26, 1997)]
[Proposed Rules]
[Pages 63042-63044]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-31023]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-200-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace BAe Model ATP 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain British Aerospace BAe 
Model ATP airplanes. This proposal would 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. This proposal is prompted 
by issuance of mandatory continuing airworthiness information by a 
foreign civil airworthiness authority. The actions specified by the 
proposed 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: Comments must be received by December 26, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-200-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from AI(R) American Support, Inc., 13850 McLearen Road, 
Herndon, Virginia 20171. This information may be examined at the FAA, 
Transport

[[Page 63043]]

Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: 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:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 96-NM-200-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 96-NM-200-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Civil Aviation Authority (CAA), which is the airworthiness 
authority for the United Kingdom, notified the FAA that an unsafe 
condition may exist on certain British Aerospace BAe Model ATP 
airplanes. The CAA advises it received reports indicating that the heat 
pack unit of the main landing gear (MLG) brake unit has exhibited 
uneven wear at the pressure stator/first rotor interface in some 
instances, which has resulted in a small number of failures of the 
pressure stator. The pressure stator failures have been attributed to 
incorrect wear remaining length (WRL) indicated by the wear indicator 
pin (WIP). Such uneven wear and/or failure of the pressure stator/first 
rotor interface of the brake units, if not corrected, could result in 
reduced braking efficiency and consequent longer stopping distances 
upon landing.

Explanation of Relevant Service Information

    Jetstream has issued Service Bulletin ATP/J61-32-71, dated May 23, 
1996, and Revision 1, dated June 18, 1996, which describe procedures 
for repetitive inspections to detect uneven wear of the heat pack of 
the MLG brake unit at the pressure stator/first rotor interface; 
measurement and setting of the WRL of the WIP to indicate the correct 
amount of allowable remaining wear of the brake heat pack unit; and 
replacement of the brake heat pack unit with a serviceable unit, if 
necessary. (The Jetstream service bulletin references Dunlop service 
Bulletin AHA1612/AHA2004-32-1122, dated April 16, 1996, as an 
additional source of service information for inspecting the brakes, 
measuring the WRL of the WIP, and setting the corrected length of the 
pin.
    The CAA classified the Jetstream service bulletin as mandatory and 
issued British airworthiness directive 002-05-96 in order to assure the 
continued airworthiness of these airplanes in the United Kingdom.

FAA's Conclusions

    This airplane model is manufactured in the United Kingdom and is 
type certificated for operation in the United States under the 
provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement. Pursuant 
to this bilateral airworthiness agreement, the CAA has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the CAA, reviewed all available information, and determined 
that AD action is necessary for products of this type design that are 
certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require accomplishment of 
the actions specified in the service bulletin described previously.

Differences Between Proposed AD and Service Information

    Operators should note that certain procedures described in the 
referenced Dunlop Service Bulletin are not included in this AD. Those 
procedures address the possible delay in the accomplishment of some of 
the work tasks due to the lack of qualified persons to set the WRL of 
the WIP. However, this AD permits no delay in setting the corrected 
length of the pin.

Cost Impact

    The FAA estimates that 10 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 5 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$3,000, or $300 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed 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 proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 draft 
regulatory 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, Safety.

[[Page 63044]]

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

British Aerospace Regional Aircraft [Formerly Jetstream Aircraft 
Limited; British Aerospace (Commercial Aircraft) Limited]: 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 
otherwise 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:
    (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, dated May 23, 1996, 
or Revision 1, dated June 18, 1996.

    Note 2: 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 wear remaining length (WRL) of the wear 
indicator pin (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 outside 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 the referenced 
service bulletin; 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 3: 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.

    Note 4: The subject of this AD is addressed in British 
airworthiness directive 002-05-96.

    Issued in Renton, Washington, on November 19, 1997.
Stewart R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-31023 Filed 11-25-97; 8:45 am]
BILLING CODE 4910-13-U