[Federal Register Volume 75, Number 190 (Friday, October 1, 2010)]
[Proposed Rules]
[Pages 60667-60669]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-24713]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0951; Directorate Identifier 2010-NM-107-AD]
RIN 2120-AA64


Airworthiness Directives; Learjet Inc. Model 45 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for all 
Model 45 airplanes. This proposed AD would require a general visual 
inspection for damage of wiring (including chafing, pinched wires, and 
exposed wires) and correct routing of wires in the left and right 
circuit breaker panels, and related investigative and corrective 
actions if necessary. This proposed AD results from reports of wire 
damage on the pilot and copilot circuit breaker panels caused by a 
short circuit between chafed wires. We are proposing this AD to detect 
and correct damaged or misrouted wires, which could result in a short 
circuit and the loss of systems associated with the wiring (including 
fire suppression function for one engine and essential avionics 
systems).

DATES: We must receive comments on this proposed AD by November 15, 
2010.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.

[[Page 60668]]

     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942; telephone 
316-946-2000; fax 316-946-2220; e-mail [email protected]; 
Internet http://www.bombardier.com. You may review copies of the 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information 
on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://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 proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Kevin Schwemmer, Aerospace Engineer, 
Electrical Systems and Avionics, ACE-119W, FAA, Wichita Aircraft 
Certification Office (ACO), 1801 Airport Road, Room 100, Mid-Continent 
Airport, Wichita, Kansas 67209; telephone (316) 946-4174; fax (316) 
946-4107.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2010-0951; 
Directorate Identifier 2010-NM-107-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We have received reports of a wire failure associated with the 
pilot and copilot circuit breaker panel that could result in toxic 
gases in the crew compartment. Wire damage caused by a short circuit 
and subsequent burning of wires have been reported on four Model 45 
airplanes. In all four incidents, the wire damage was associated with 
the 28 volts direct current (VDC) power for the fire-suppression 
system. This condition, if not corrected, could result in wire damage 
caused by a short circuit, which could result in the loss of systems 
associated with the wiring (including fire suppression function for one 
engine and essential avionics systems).

Relevant Service Information

    We have reviewed Bombardier Alert Service Bulletin A40-24-11, dated 
November 16, 2009; and Bombardier Alert Service Bulletin A45-24-16, 
dated November 16, 2009. The service information describes procedures 
for doing a general visual inspection for damage of wiring (including 
chafing, pinched wires, and exposed wires) and correct routing of wires 
in the left and right circuit breaker panels, and related investigative 
and corrective actions, if necessary. The related investigative action 
is doing a general visual inspection for arcing damage on the mounting 
brackets of the forward circuit breaker panel. Depending on inspection 
findings, the corrective actions are replacing damaged (chafed, 
pinched, or exposed) wires, and re-routing any incorrectly routed 
wires; and contacting the manufacturer for repair instructions and 
doing the repair.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously, except as discussed under 
``Differences Between the Proposed AD and Service Bulletin.''

Differences Between the Proposed AD and Service Bulletin

    Although Bombardier Alert Service Bulletin A40-24-11, dated 
November 16, 2009; and Bombardier Alert Service Bulletin A45-24-16, 
dated November 16, 2009; specify that operators may contact the 
manufacturer for disposition of certain repair conditions, this 
proposed AD would require operators to repair those conditions using a 
method approved by the FAA.

Costs of Compliance

    We estimate that this proposed AD would affect 339 airplanes of 
U.S. registry. We also estimate that it would take about 1 work-hour 
per product to comply with this proposed AD. The average labor rate is 
$85 per work-hour. Based on these figures, we estimate the cost of this 
proposed AD to the U.S. operators to be $28,815, or $85 per product.

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 products identified in this 
rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 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. 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

[[Page 60669]]

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new AD:

Learjet Inc.: Docket No. FAA-2010-0951; Directorate Identifier 2010-
NM-107-AD.

Comments Due Date

    (a) We must receive comments by November 15, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Learjet Inc. Model 45 airplanes, 
certificated in any category; having serial numbers identified in 
paragraphs (c)(1) and (c)(2) of this AD.
    (1) Serial numbers 45-2001 through 45-2114 inclusive, 45-2116 
through 45-2120 inclusive, 45-2122, 45-2125, and 45-2126.
    (2) Serial numbers 45-005 through 45-380 inclusive, 45-382 
through 45-391 inclusive, 45-393 through 45-396 inclusive, 45-398, 
45-400, 45-401, and 45-403.

Subject

    (d) Air Transport Association (ATA) of America Code 24: 
Electrical power.

Unsafe Condition

    (e) This AD results from reports of wire damage on the pilot and 
copilot circuit breaker panels caused by a short circuit between 
chafed wires. The Federal Aviation Administration is issuing this AD 
to detect and correct damaged or misrouted wires, which could result 
in a short circuit and the loss of systems associated with the 
wiring (including fire suppression function for one engine and 
essential avionics systems).

Compliance

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

Inspection and Corrective Action

    (g) Within 50 flight hours after the effective date of this AD: 
Do a general visual inspection for damage of wiring and correct 
routing of wires in the left and right circuit breaker panels, and 
all applicable related investigative and corrective actions, in 
accordance with the Accomplishment Instructions of Bombardier Alert 
Service Bulletin A40-24-11, dated November 16, 2009; or Bombardier 
Alert Service Bulletin A45-24-16, dated November 16, 2009; as 
applicable; except if arcing damage is found on the mounting 
brackets of the forward circuit breaker panel, before further 
flight, repair in accordance with a method approved by the Manager, 
Wichita Aircraft Certification Office, FAA. Do all applicable 
related investigative and corrective actions before further flight.

    Note 1: For the purposes of this AD, a general visual inspection 
is: ``A visual examination of an interior or exterior area, 
installation, or assembly to detect obvious damage, failure, or 
irregularity. This level of inspection is made from within touching 
distance unless otherwise specified. A mirror may be necessary to 
ensure visual access to all surfaces in the inspection area. This 
level of inspection is made under normally available lighting 
conditions such as daylight, hangar lighting, flashlight, or 
droplight and may require removal or opening of access panels or 
doors. Stands, ladders, or platforms may be required to gain 
proximity to the area being checked.''

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Wichita Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. Send information to 
ATTN: Kevin Schwemmer, Aerospace Engineer, Electrical Systems and 
Avionics, ACE-119W, FAA, Wichita Aircraft Certification Office 
(ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, 
Kansas 67209; telephone (316) 946-4174; fax (316) 946-4107.
    (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 principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.

    Issued in Renton, Washington, on September 24, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-24713 Filed 9-30-10; 8:45 am]
BILLING CODE 4910-13-P