Airworthiness Directives; Learjet Model 45 Airplanes, 1815-1816 [E8-163]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 73, Number 7 (Thursday, January 10, 2008)]
[Rules and Regulations]
[Pages 1815-1816]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-163]



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Federal Register / Vol. 73, No. 7 / Thursday, January 10, 2008 / 
Rules and Regulations

[[Page 1815]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25174; Directorate Identifier 2005-NM-007-AD; 
Amendment 39-15328; AD 2008-01-03]
RIN 2120-AA64


Airworthiness Directives; Learjet Model 45 Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Learjet Model 45 airplanes. This AD requires revising the 
Airworthiness Limitations section of the airplane maintenance manual to 
incorporate certain inspections and compliance times to detect fatigue 
cracking of certain principal structural elements (PSEs). This AD 
results from new and more restrictive life limits and inspection 
intervals for certain PSEs. We are issuing this AD to ensure that 
fatigue cracking of various PSEs is detected and corrected; such 
fatigue cracking could adversely affect the structural integrity of 
these airplanes.

DATES: This AD becomes effective February 14, 2008.

ADDRESSES: For service information identified in this AD, contact 
Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942.

Examining the AD Docket

    You may examine the AD docket on the Internet at https://
www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the Document Management 
Facility, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Steve Litke, Aerospace Engineer, 
Airframe and Services Branch, ACE-118W, FAA, Wichita Aircraft 
Certification Office, 1801 Airport Road, Room 100, Mid-Continent 
Airport, Wichita, Kansas 67209; telephone (316) 946-4127; fax (316) 
946-4107.

SUPPLEMENTARY INFORMATION: 

Discussion

    The FAA issued a supplemental notice of proposed rulemaking (NPRM) 
to amend 14 CFR part 39 to include an AD that would apply to certain 
Learjet Model 45 airplanes. That supplemental NPRM was published in the 
Federal Register on June 18, 2007 (72 FR 33415). That supplemental NPRM 
proposed to require revising the Airworthiness Limitations section 
(ALS) of the airplane maintenance manual to incorporate certain 
inspections and compliance times to detect fatigue cracking of certain 
principal structural elements (PSEs).

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the single comment received.

Request To Clarify Paragraph (f) of the Supplemental NPRM

    Averitt Air states that the supplemental NPRM lists Chapter 4 of 
the Learjet 45 Maintenance Manual, Revision 38, dated April 24, 2006, 
as a means of compliance with the supplemental NPRM. Averitt points out 
that the maintenance manual is currently at Revision 39, with Revision 
40 coming soon. Averitt states that as the supplemental NPRM is 
currently worded, with each revision to the maintenance manual the 
operator will have to review Chapter 4 of the maintenance manual to 
ensure no changes have been made. Averitt also points out that each 
operator is required by Federal Aviation Regulations (FARs) to comply 
with the latest revision of the airworthiness limitations for his 
aircraft. Averitt questions the issuance of the AD at this time. 
Averitt states that the manufacturer of Learjet Model 45 airplanes is 
proactive in advising the operator of revisions to the maintenance 
manual.
    We infer that Averitt would like us to put words in the AD that 
allow for the use of later revisions of the maintenance manual. As 
Averitt notes, operators must comply with the terms of the ALS, as 
specified in sections 43.16 (for persons maintaining products) and 
91.403 (for operators) of the Federal Aviation Regulations (14 CFR 
43.16 and 14 CFR 91.403). However, for the FAA to require compliance 
with any new or more restrictive life limits and inspections that the 
manufacturer or the FAA might impose in the ALS, we must engage in 
rulemaking; if we do not engage in rulemaking, the revised limitations 
in the maintenance manual cannot be made mandatory. We do, however, 
agree with Averitt's request to allow accomplishing the AWL revision in 
accordance with later revisions. We have revised paragraph (f) of this 
AD to allow later revisions of the maintenance manuals as acceptable 
methods of compliance if they are approved by the Manager, Wichita 
Aircraft Certification Office (ACO), FAA.

Conclusion

    We reviewed the relevant data, considered the comment received, and 
determined that air safety and the public interest require adopting the 
AD with the change described previously. We also determined that this 
change will not increase the economic burden on any operator or 
increase the scope of the AD.

Costs of Compliance

    There are about 347 airplanes of the affected design in the 
worldwide fleet. This AD affects about 258 airplanes of U.S. registry. 
The actions take about 1 work hour per airplane, at an average labor 
rate of $80 per work hour. Based on these figures, the estimated cost 
of this AD for U.S. operators is $20,640, or $80 per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of

[[Page 1816]]

the FAA Administrator. Subtitle VII, Aviation Programs, describes in 
more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

2008-01-03 Learjet: Amendment 39-15328. Docket No. FAA-2006-25174; 
Directorate Identifier 2005-NM-007-AD.

Effective Date

    (a) This AD becomes effective February 14, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Learjet Model 45 airplanes, certificated 
in any category; serial numbers (S/Ns) 45-002 through 45-302 
inclusive, and S/Ns 45-2001 through 45-2049 inclusive.

Unsafe Condition

    (d) This AD results from new and more restrictive life limits 
and inspection intervals for certain principal structural elements 
(PSEs). We are issuing this AD to ensure that fatigue cracking of 
various PSEs is detected and corrected; such fatigue cracking could 
adversely affect the structural integrity of these airplanes.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

    Note 1: This AD requires revisions to certain operator 
maintenance documents to include new inspections. Compliance with 
these inspections is required by 14 CFR 91.403(c). For airplanes 
that have been previously modified, altered, or repaired in the 
areas addressed by these inspections, the operator may not be able 
to accomplish the inspections described in the revisions. In this 
situation, to comply with 14 CFR 91.403(c), the operator must 
request approval for an alternative method of compliance (AMOC) 
according to paragraph (g) of this AD. The request should include a 
description of changes to the required inspections that will ensure 
the continued damage tolerance of the affected structure. The FAA 
has provided guidance for this determination in Advisory Circular 
(AC) 25.1529-1.

Revise the Airworthiness Limitations Section (ALS)

    (f) Within 30 days after the effective date of this AD, revise 
the ALS of the airplane maintenance manual (AMM) to include new life 
limits and inspection intervals according to a method approved by 
the Manager, Wichita Aircraft Certification Office (ACO), FAA. 
Incorporating the applicable chapters specified in paragraph (f)(1) 
or (f)(2) of this AD in the AMM is one approved method for doing the 
revision. Accomplishing the revision in accordance with a later 
approved revision of the applicable maintenance manual is an 
acceptable method of compliance if the revision is approved by the 
Manager, Wichita ACO, FAA. Thereafter, no alternative life limits or 
inspection intervals may be used for the affected PSEs, unless the 
limit or interval is part of a later approved AMM revision or the 
limit or interval is approved as an alternative method of compliance 
(AMOC) in accordance with the procedures specified in paragraph (g) 
of this AD.
    (1) For Learjet Model 45 airplanes, S/Ns 45-002 through 45-302 
inclusive: Chapter 4 of the Learjet 45 Maintenance Manual, Revision 
38, dated April 24, 2006.
    (2) For Learjet Model 45 airplanes, S/Ns 45-2001 through 45-2049 
inclusive: Chapter 4 of the Learjet 40 Maintenance Manual, Revision 
6, dated April 24, 2006.

    Note 2: After an operator complies with the requirements of 
paragraph (f) of this AD, that paragraph does not require that 
operators subsequently record accomplishment of those requirements 
each time an action is accomplished according to that operator's 
FAA-approved maintenance inspection program.

AMOCs

    (g)(1) The Manager, Wichita ACO, has the authority to approve 
AMOCs for this AD, if requested in accordance with the procedures 
found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.

Material Incorporated by Reference

    (h) None.

    Issued in Renton, Washington, on December 21, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E8-163 Filed 1-9-08; 8:45 am]
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