[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]
[[Page 50022]]
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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