Airworthiness Directives; Learjet Model 45 Airplanes

[Federal Register Volume 72, Number 80 (Thursday, April 26, 2007)]
[Rules and Regulations]
[Pages 20716-20718]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-7640]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27980; Directorate Identifier 2007-NM-066-AD; 
Amendment 39-15033; AD 2007-09-03]
RIN 2120-AA64


Airworthiness Directives; Learjet Model 45 Airplanes

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

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Learjet Model 45 airplanes. This AD requires deactivating the 
auxiliary power unit (APU), capping/plugging the fuel lines to the APU, 
and removing the APU fuel shutoff valve. This AD results from reports 
of fuel leaking from the APU fuel shutoff valve into a flammable fluid 
fire protection area that is also interconnected with the main landing 
gear's wheel well bay. We are issuing this AD to prevent fuel leaking 
from the fuel shutoff valve of the APU, which could result in an 
uncontrollable fire and adversely affect the airplane's continued safe 
flight and landing.

DATES: This AD becomes effective May 11, 2007.
    The Director of the Federal Register approved the incorporation by 
reference

[[Page 20717]]

of a certain publication listed in the AD as of May 11, 2007.
    We must receive comments on this AD by June 25, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this AD.
    <bullet> DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
    <bullet> Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
    <bullet> Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
    <bullet> Fax: (202) 493-2251.
    <bullet> Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, 
for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: James P. Galstad, Aerospace Engineer, 
Mechanical Systems and Propulsion Branch, ACE-116W, FAA, Wichita 
Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-
Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4135; fax 
(316) 946-4107.

SUPPLEMENTARY INFORMATION: 

Discussion

    We have received a report indicating that there have been 16 
occurrences of fuel leaking from the fuel shutoff valve of the 
auxiliary power unit (APU), on Model 45 airplanes in the field and on 
the production line. Epoxy was used in the valve to seal or adhere 
certain components of the valve. The epoxy was found to have been 
improperly prepared and/or applied, which allowed fuel to leak out 
through and/or around the electrical switch and connector in the bottom 
of the valve. Some valves were also found to have internal leaks due to 
fuel-soaked silicone sealant that had expanded into the electrical 
switch's location. The APU's fuel shutoff valve leaks fuel into a 
flammable fluid fire protection area that is also interconnected with 
the main landing gear's wheel well bay. This condition, if not 
corrected, could result in an uncontrollable fire, which could 
adversely affect the airplane's continued safe flight and landing.

Relevant Service Information

    We have reviewed Bombardier Alert Service Bulletin A45-49-11, dated 
March 26, 2007. The service bulletin describes procedures for 
deactivating the APU, capping/plugging the fuel lines to the APU, and 
removing the APU fuel shutoff valve. Deactivating the APU also involves 
attaching inoperative APU placards in various locations. The service 
bulletin also describes procedures for sending the removed APU shutoff 
valves and compliance information to Learjet.

FAA's Determination and Requirements of This AD

    The unsafe condition described previously is likely to exist or 
develop on other airplanes of the same type design. For this reason, we 
are issuing this AD to prevent fuel leaking from the fuel shutoff valve 
of the APU, which could result in an uncontrolled fire and adversely 
affect the airplane's continued safe flight and landing. This AD 
requires accomplishing the actions specified in the service information 
described previously, except as discussed under ``Differences Between 
the AD and the Service Bulletin.''

Differences Between the AD and the Service Bulletin

    Operators should note that, although the Accomplishment 
Instructions of the referenced service bulletin describe procedures for 
returning the APU's fuel shutoff valve to Learjet, this AD does not 
require that action.
    Operators should also note that, although the Accomplishment 
Instructions of the referenced service bulletin describe procedures for 
submitting a compliance response form for recording compliance with the 
service bulletin, this AD does not require that action.

Interim Action

    This AD is considered to be interim action. The manufacturer has 
advised us that it currently is developing a modification that will 
address the unsafe condition addressed by this AD. Once this 
modification is approved, we may consider additional rulemaking.

FAA's Determination of the Effective Date

    Since an unsafe condition exists that requires the immediate 
adoption of this AD, we have found that notice and opportunity for 
public comment before issuing this AD are impracticable, and that good 
cause exists to make this AD effective in less than 30 days.

Comments Invited

    This AD is a final rule that involves requirements that affect 
flight safety and was not preceded by notice and an opportunity for 
public comment; however, we invite you to submit any relevant written 
data, views, or arguments regarding this AD. Send your comments to an 
address listed in the ADDRESSES section. Include ``Docket No. FAA-2007-
27980; Directorate Identifier 2007-NM-066-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the AD that might 
suggest a need to modify it.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this AD. Using the search function of that web 
site, anyone can find and read the comments in any of our dockets, 
including the name of the individual who sent the comment (or signed 
the comment on behalf of an association, business, labor union, etc.). 
You may review the DOT's complete Privacy Act Statement in the Federal 
Register published on April 11, 2000 (65 FR 19477-78), or you may visit 
http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

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 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

[[Page 20718]]

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 the 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. 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, Incorporation by 
reference, 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):

2007-09-03 LEARJET: Amendment 39-15033. Docket No. FAA-2007-27980; 
Directorate Identifier 2007-NM-066-AD.

Effective Date

    (a) This AD becomes effective May 11, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Learjet Model 45 airplanes, certificated 
in any category; serial numbers 45-005 through 45-321, equipped with 
an auxiliary power unit (APU).

Unsafe Condition

    (d) This AD results from reports of fuel leaking from the APU 
fuel shutoff valve into a flammable fluid fire protection area that 
is also interconnected with the main landing gear's wheel well bay. 
We are issuing this AD to prevent fuel leaking from the fuel shutoff 
valve of the APU, which could result in an uncontrollable fire and 
adversely affect the airplane's continued safe flight and landing.

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.

Deactivation of the APU and Removal of the APU Fuel Shutoff Valve

    (f) Within 50 flight hours after the effective date of this AD, 
deactivate the APU, cap/plug the fuel lines to the APU, and remove 
the APU fuel shutoff valve, in accordance with the Accomplishment 
Instructions of Bombardier Alert Service Bulletin A45-49-11, dated 
March 26, 2007.

Differences From the Service Information

    (g) Although Bombardier Alert Service Bulletin A45-49-11, dated 
March 26, 2007, specifies to submit certain information to the 
manufacturer and send the APU fuel shutoff valve to Learjet, this AD 
does not include those requirements.

Special Flight Permit

    (h) 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, provided the APU is 
not used.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Wichita Aircraft Certification Office (ACO), 
FAA, 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

    (j) You must use Bombardier Alert Service Bulletin A45-49-11, 
dated March 26, 2007, to perform the actions that are required by 
this AD, unless the AD specifies otherwise. The Director of the 
Federal Register approved the incorporation by reference of this 
document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
Contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, 
for a copy of this service information. You may review copies at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on April 16, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-7640 Filed 4-25-07; 8:45 am]
BILLING CODE 4910-13-P

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