[Federal Register Volume 64, Number 178 (Wednesday, September 15, 1999)]
[Proposed Rules]
[Pages 50022-50023]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-24091]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-114-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 and 767 Series 
Airplanes Powered by Pratt & Whitney PW4000 Series Engines

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 747-400 and 
767 series airplanes. This proposal would require replacement of the 
existing deactivation pin, pin bushing, and insert flange on each 
thrust reverser half, with new, improved components. This proposal is 
prompted by reports of partial deployment of deactivated thrust 
reversers during landing. The actions specified by the proposed AD are 
intended to prevent failure of the thrust reverser deactivation pins, 
which could result in deployment of the thrust reverser in flight and 
consequent reduced controllability of the airplane.

DATES: Comments must be received by November 1, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-114-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: Dorr Anderson, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2684; 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-114-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-114-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of partial deployments of deactivated 
thrust reversers during landing on Boeing Model 767 series airplanes 
powered by Pratt & Whitney PW4000 series engines. Subsequent 
investigation revealed that, in each event, the thrust reverser had 
been improperly deactivated. This allowed hydraulic pressure to be 
available to the actuators when the reverse thrust levers were 
activated on landing. The pin insert for the deactivation pin was not 
able to withstand the load of a powered deployment and failed. The 
deactivation pin, as well as the pin insert flange, are subject to 
adverse tolerance stack-up, which minimizes their load carrying 
capability, and the pin and insert flanges may not prevent a 
deactivated thrust reverser sleeve from moving during a powered 
deployment. This condition, if not corrected, could result in 
deployment of the thrust reverser in flight and consequent reduced 
controllability of the airplane. The deactivation pins, pin bushings, 
and insert flanges on Model 747-400 series airplanes powered by Pratt & 
Whitney PW4000 series engines are the same as those on the affected 
Model 767 series airplanes. Therefore, those Model 747-400 series 
airplanes may be subject to the same unsafe condition.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 747-
78A2165, Revision 1, dated May 13, 1999, which describes procedures for 
replacement of the existing deactivation pin, pin bushing, and insert 
flange on each thrust reverser half, with new, improved components, on 
Model 747-400 series airplanes powered by Pratt & Whitney PW4000 series 
engines. The FAA has also reviewed and approved Boeing Alert Service 
Bulletin 767-78A0080, dated February 25, 1999, which describes 
procedures for replacement of the existing deactivation pin, pin 
bushing, and insert flange on each thrust reverser half, with new, 
improved components, on Model 767 series airplanes powered by Pratt & 
Whitney PW4000 series engines. Accomplishment of the actions specified 
in the service bulletins 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 type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletins described previously, except as described below.

Differences Between The Proposed AD and the Service Bulletins

    Boeing Service Bulletin 747-78A2165, Revision 1, and Boeing Alert 
Service Bulletin 767-78A0080 recommend incorporation of the specified 
actions on airplanes with the additional thrust reverser locks at the 
earliest opportunity where facilities and manpower are available. For 
airplanes without additional thrust reverser locks, the service 
bulletins recommend incorporation at the earliest opportunity where 
facilities and manpower are available but no later than 24 months. In 
developing an appropriate compliance time for this AD, the FAA 
considered not only the manufacturer's

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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 replacement. In light of 
all of these factors, the FAA finds a 24-month compliance time for 
accomplishing the required actions on all affected airplanes 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 201 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 39 Model 747-400 series 
airplanes and 54 Model 767 series airplanes of U.S. registry would be 
affected by this proposed AD. It would take approximately 6 work hours 
per engine to accomplish the proposed replacement, at an average labor 
rate of $60 per work hour. Required parts would cost approximately 
$3,956 per engine. Based on these figures, the cost impact of the 
proposed AD on U.S. operators of Model 747-400 series airplanes (4 
engines per airplane) is estimated to be $673,296, or $17,264 per 
airplane. The cost impact of the proposed AD on U.S. operators of Model 
767 series airplanes (2 engines per airplane) is estimated to be 
$466,128, or $8,632 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.

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-114-AD.

    Applicability: Model 747-400 series airplanes powered by Pratt & 
Whitney PW4000 series engines, as listed in Boeing Service Bulletin 
747-78A2165, Revision 1, dated May 13, 1999; and Model 767 series 
airplanes powered by Pratt & Whitney PW4000 series engines, as 
listed in Boeing Alert Service Bulletin 767-78A0080, dated February 
25, 1999; 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 failure of the thrust reverser deactivation pins, 
which could result in deployment of the thrust reverser in flight 
and consequent reduced controllability of the airplane, accomplish 
the following:

Replacement

    (a) Within 24 months after the effective date of this AD, 
replace the existing deactivation pin, pin bushing in the aft 
cascade mounting ring, and insert flange on each thrust reverser 
half, with new, improved components, in accordance with Boeing 
Service Bulletin 747-78A2165, Revision 1, dated May 13, 1999 (for 
Model 747-400 series airplanes); or Boeing Alert Service Bulletin 
767-78A0080, dated February 25, 1999 (for Model 767 series 
airplanes); as applicable.

    Note 2: The new, improved insert flange and pin bushing does not 
preclude use of a deactivation pin having P/N 315T1604-2 or -5. 
However, use of deactivation pins having P/N 315T1604-2 or -5 may 
not prevent the thrust reversers from deploying in event of a full 
powered deployment. Therefore, thrust reversers modified per this AD 
require installation of the new, longer deactivation pins having P/N 
315T1604-6, as specified in the applicable service bulletin.
    Note 3: Replacements accomplished prior to the effective date of 
this AD in accordance with Boeing Alert Service Bulletin 747-
78A2165, dated February 25, 1999, are considered acceptable for 
compliance with the applicable action specified in this amendment.

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

Special Flight Permits

    (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 September 9, 1999.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-24091 Filed 9-14-99; 8:45 am]
BILLING CODE 4910-13-U