[Federal Register Volume 61, Number 105 (Thursday, May 30, 1996)]
[Proposed Rules]
[Pages 27030-27031]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-13498]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-240-AD]
RIN 2120-AA64
Airworthiness Directives; Learjet Model 60 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 Learjet Model 60
airplanes. This proposal would require modification of the aft core
cowl nozzle of the engine nacelles. This proposal is prompted by a
report that the sealant material in the aft core cowl nozzle of the
engine nacelle was found to extend higher than the nozzle's forward
flange, which can allow it to interfere with the proper operation of
the emergency fuel shutoff actuating mechanism. The actions specified
by the proposed AD are intended to prevent physical interference of the
emergency fuel shutoff actuating mechanism and resultant engine
shutdown.
DATES: Comments must be received by July 8, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-240-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 Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-
2942. This information may be examined at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA,
Small Airplane Directorate, Wichita Aircraft Certification Office, 1801
Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas.
FOR FURTHER INFORMATION CONTACT: Jeffrey Janusz, Aerospace Engineer,
Systems and Propulsion Branch, ACE-116W, FAA, Small Airplane
Directorate, Wichita Aircraft Certification Office, 1801 Airport Road,
Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316)
946-4148; fax (316) 946-4407.
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 95-NM-240-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. 95-NM-240-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion -
The FAA has received a report that, during installation of the aft
core cowl nozzle of the engine nacelle on a Learjet Model 60 airplane,
the sealant material in the aft core cowl nozzle was found to be
improperly extended higher than the nozzle's forward flange. The cause
has been attributed to the apparent improper installation of the
sealant material during production. Sealant material in the aft core
cowl nozzle that extends too high, if not corrected, could interfere
with proper operation of the lever of the emergency fuel shutoff
actuating mechanism. Such interference could result in the failure of
the emergency fuel shutoff actuating mechanism and resultant engine
shutdown. -
The FAA has reviewed and approved Learjet Service Bulletin SB 60-
71-2, dated May 12, 1995, which describes procedures for modification
of the aft core cowl nozzle of the engine nacelles. Among other
actions, the modification involves replacing the sealant on the aft
core cowl nozzle with a filler made from 6061 aluminum, and
reidentifying the aft core cowl nozzle. The modification will ensure
that the sealant does not interfere with the function of the emergency
fuel shutoff actuating mechanism. -
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 modification of the aft core cowl nozzle of
the engine nacelles. The actions would be required to be accomplished
in accordance with the service bulletin described previously. -
There are approximately 39 Learjet Model 60 airplanes of the
affected design in the worldwide fleet. The FAA estimates that 26
airplanes of U.S. registry would be affected by this proposed AD, that
it would take approximately 44 work hours per airplane to accomplish
the proposed actions, and that the average labor rate is $60 per work
hour. Required parts would be supplied by the manufacturer at no cost
to the operators. Based on these figures, the cost impact of the
proposed AD on U.S. operators is estimated to be $68,640, or $2,640 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. -
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
[[Page 27031]]
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:
Learjet: Docket 95-NM-240-AD.
-Applicability: Model 60 airplanes, as listed in Learjet
Service Bulletin SB 60-71-2, dated May 12, 1995; 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 (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 the sealant material in the aft core cowl nozzle of
the engine nacelles from interfering with the lever of the emergency
fuel shutoff actuating mechanism, which could result in the failure
of the emergency fuel shutoff actuating mechanism and resultant
engine shutdown, accomplish the following: -
(a) Within 90 days after the effective date of this AD, modify
the aft core cowl nozzle of the engine nacelles in accordance with
Learjet Service Bulletin SB 60-71-2, dated May 12, 1995. -
(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, Wichita Aircraft Certification
Office (ACO), FAA, Small 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, Wichita ACO.
-Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Wichita ACO.
-(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 May 22, 1996.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-13498 Filed 5-29-96; 8:45 am]
BILLING CODE 4910-13-U
