[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