[Federal Register Volume 64, Number 167 (Monday, August 30, 1999)]
[Proposed Rules]
[Pages 47148-47149]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22396]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-15-AD]
RIN 2120-AA64
Airworthiness Directives; Learjet Model 31, 31A, 35, 35A, and 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 31, 31A, 35,
35A, and 60 airplanes. This proposal would require a visual inspection
of the spoiler actuators to determine the serial number of the spoiler
actuators; and replacement of the spoiler actuators with new actuators,
if necessary. This proposal is prompted by failure of a spoiler
actuator piston rod during the first production flight of a Model 60
airplane due to an incomplete heat treatment process. The actions
specified by the proposed AD are intended to prevent failure of the
spoiler actuator, which could result in the spoiler panel floating and
inducing an uncommanded roll of the airplane.
DATES: Comments must be received by October 14, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 99-NM-15-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: Shane Bertish, Aerospace Engineer,
Systems and Equipment Branch, ACE-116W, FAA, Small Airplane
Directorate, Wichita Aircraft Certification Office, 1801 Airport Road,
Room 100, Mid-Continent Airport, Wichita, Kansas 67209, telephone (316)
946-4156; 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 99-NM-15-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-15-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received a report of failure of the spoiler actuator
piston rod on the first production flight of a Learjet Model 60
airplane. Investigation revealed that a group of actuator piston rods
had undergone an incomplete heat treating process that failed to
achieve the desired material properties. This condition, if not
corrected, could result in the spoiler panel floating and inducing an
uncommanded roll of the airplane.
The subject spoiler actuator piston rods on Learjet Model 31, 31A,
35, and 35A airplanes are identical to those on the affected Learjet
Model 60 airplanes. Therefore, all of these airplanes may be subject to
the same unsafe condition.
Explanation of Relevant Service Information
The FAA has reviewed and approved Learjet Service Bulletins SB 31-
27-19, dated December 14, 1998 (for Model 31 and 31A airplanes); SB 35-
27-36, dated December 14, 1998 (for Model 35 and 35A airplanes); and SB
60-27-21, dated December 14, 1998 (for Model 60 airplanes). These
service bulletins describe procedures for a visual inspection of the
spoiler actuators to determine the serial number of the spoiler
actuators; and replacement of the spoiler actuators with new actuators,
if necessary. 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 applicable service bulletin described previously.
Cost Impact
There are approximately 45 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 37 airplanes of U.S. registry
would be affected by this proposed AD, that it would take approximately
1 work hour per airplane to accomplish the proposed inspection, and
that the average labor rate is $60 per work hour. Based on these
figures, the cost impact of the
[[Page 47149]]
proposed AD on U.S. operators is estimated to be $2,220, or $60 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 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:
Learjet, Inc.: Docket 99-NM-15-AD.
Applicability: Model 31 and 31A airplanes, serial numbers 31-
033, 31-105, 31-114, 31-126, and 31-150 through 31-161 inclusive;
Model 35 and 35A airplanes, serial numbers 35-065, 35-242, 35-300,
35-323, 35-447, 35-622, and 35-670; and Model 60 airplanes, serial
numbers 60-029, 60-050, 60-120 through 60-139 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 failure of the spoiler actuator, which could result
in the spoiler panel floating and inducing an uncommanded roll of
the airplane, accomplish the following:
Inspection and Replacement
(a) Within 150 flight hours after the effective date of this AD,
perform a visual inspection to determine the serial number of the
spoiler actuators, in accordance with Learjet Service Bulletins SB
31-27-19, dated December 14, 1998 (for Model 31 and 31A airplanes);
SB 35-27-36, dated December 14, 1998 (for Model 35 and 35A
airplanes); or SB 60-27-21, dated December 14, 1998 (for Model 60
airplanes); as applicable.
(1) If the serial number is not listed in the applicable service
bulletin, no further action is required by this AD.
(2) If the serial number is listed in the applicable service
bulletin, prior to further flight, replace the spoiler actuators
with new actuators in accordance with the Accomplishment
Instructions of the applicable service bulletin.
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, 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.
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 August 23, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-22396 Filed 8-27-99; 8:45 am]
BILLING CODE 4910-13-P
