[Federal Register Volume 65, Number 24 (Friday, February 4, 2000)]
[Proposed Rules]
[Pages 5455-5456]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-2414]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-374-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767 Series 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 Boeing Model 767 series 
airplanes. This proposal would require modification of the canted 
pressure deck drain system in the wheel well of the main landing gear 
(MLG). This proposal is prompted by reports of ice accumulation on the 
aileron control cables and on the MLG door and door seal, during 
flight, due to fluid entering the canted pressure deck area, leaking 
into the MLG wheel well, and freezing. The actions specified by the 
proposed AD are intended to prevent such ice accumulation, which could 
render one of the aileron control systems and/or the MLG doors 
inoperative, resulting in reduced controllability of the airplane.

DATES:  Comments must be received by March 20, 2000.

ADDRESSES:  Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-374-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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207.
    This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:  James G. Rehrl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2783; fax (425) 227-1181.

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 99-NM-374-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-114, Attention: Rules 
Docket No. 99-NM-374-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received several reports indicating ice accumulation on 
the aileron control cables in the wheel well of the main landing gear 
(MLG) during flight on certain Model 767 series airplanes. The ice 
build-up was attributed to fluid from the sloping pressure deck leaking 
into the wheel well and freezing. One operator reported a large volume 
of fluid had leaked into the canted pressure deck area and ice had 
accumulated on the MLG door and door seal inside and outside the MLG 
wheel well. The ice caused the MLG door to jam and prevented extension 
of the MLG. Investigation revealed that fluid entered the canted 
pressure deck area through the sloping pressure deck seals and 
subsequently leaked into the wheel well and solidified. Such ice 
accumulation could render one of the aileron control systems and/or the 
MLG doors inoperative, resulting in reduced controllability of the 
airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 767-
51A0020, Revision 1, dated July 22, 1999, which describes procedures 
for modification of the canted pressure deck drain system in the wheel 
well of the MLG. The modification includes, among other things, 
installation of canisters on the outboard pressure activated drain 
lines, re-routing of the existing drain lines, and installation of 
larger diameter drain lines to drain the water out through the 
underwing fairing thermal panel into the hot air stream from the ram 
outlets.
    Accomplishment of the actions specified in the service bulletin 
described previously is intended to adequately address the identified 
unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same

[[Page 5456]]

type design, the proposed AD would require modification of the canted 
pressure deck drain system in the wheel well of the MLG. The actions 
would be required to be accomplished in accordance with the service 
bulletin described previously, except as discussed below.

Difference Between Service Bulletin and This Proposed AD

    Operators should note that, although the service bulletin 
recommends accomplishment of the modification at the first available 
maintenance period as soon as parts, manpower, and facilities are 
available, the FAA has determined that a 24-month compliance time would 
address the identified unsafe condition in a timely manner. In 
developing an appropriate compliance time for this AD, the FAA 
considered not only the manufacturer's recommendation, but the degree 
of urgency associated with addressing the subject unsafe condition, the 
average utilization of the affected fleet, and the time necessary to 
perform the modification. In light of all of these factors, the FAA 
finds a 24-month compliance time for completion of the proposed 
modification to be warranted, in that it represents an appropriate 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety.

Cost Impact

    There are approximately 716 Model 767 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 278 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 15 work hours per airplane to accomplish 
the proposed modification, and that the average labor rate is $60 per 
work hour. Required parts would cost approximately $6,623 per airplane. 
Based on these figures, the cost impact of the modification proposed by 
this AD on U.S. operators is estimated to be $2,091,394, or $7,523 per 
airplane.
    The cost impact figure discussed above is 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 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 proposal would not have federalism implications 
under Executive Order 13132.
    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.

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:

Boeing: Docket 99-NM-374-AD.

    Applicability: Model 767 series airplanes, line numbers 1 
through 723 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 (b) 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 prevent ice accumulation on the aileron control cables and/or 
main landing gear (MLG) door and door seal during flight, which 
could render one of the aileron control systems and/or the MLG doors 
inoperative, resulting in reduced controllability of the airplane, 
accomplish the following:
    (a) Within 24 months after the effective date of this AD: Modify 
the canted pressure deck drain system in the wheel well of the MLG 
in accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 767-51A0020, Revision 1, dated July 22, 1999.


    Note 2:  Modification of the canted pressure deck drain system 
accomplished prior to the effective date of this AD in accordance 
with Boeing Alert Service Bulletin 767-51A0020, dated November 19, 
1998, is considered acceptable for compliance with the modification 
specified in this AD.


Alternative Methods of Compliance

    (b) 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, Seattle Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note 3:  Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (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.

    Issued in Renton, Washington, on January 28, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-2414 Filed 2-3-00; 8:45 am]
BILLING CODE 4910-13-U