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AGENCY: Federal Aviation Administration
(FAA), DOT.
ACTION: Final rule; request for comments.
SUMMARY: We are adopting a new airworthiness directive (AD) for
certain Learjet Model 45 airplanes. For certain airplanes, this AD requires
repetitive inspections for chafing and other damage of the case drain
tube from the hydraulic pump case installed on the left-hand engine, and
corrective action if necessary. This AD also requires, for all airplanes,
repetitive inspections for discrepancies of the left engine's nacelle
tubing, repetitive inspections for evidence of fluid leakage within the
left engine accessory compartment, and corrective actions if necessary.
This AD was prompted by reports of chafed hydraulic tubes in the left-hand
engine. We are issuing this AD to detect and correct chafed hydraulic
tubes in the left-hand engine and consequent hydraulic tube failure and
uncontrolled loss of flammable fluid within the engine cowling, which
could result in a fire in the engine nacelle and loss of control of the
airplane.
DATES: This AD is effective June 17, 2009.
The Director of the Federal Register approved the incorporation by reference
of certain publications listed in the AD as of June 17, 2009.
We must receive comments on this AD by August 3, 2009.
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.
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 AD, contact Learjet, Inc.,
One Learjet Way, Wichita, Kansas 67209-2942; telephone 316-946- 2000;
fax 316-946-2220; e-mail ac.ict@aero.bombardier.com; Internet http://www.bombardier.com.
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 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: James P. Galstad, Aerospace Engineer,
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 reports of chafing found on hydraulic tubing in the left-hand
engine. Specifically, the chafing was found on a case drain tube from
the hydraulic pump case installed on the left-hand engine, on the lower
forward cowl latch structure on the inboard side of the engine. Chafing
was also found on a hydraulic pressure tube, on the hydraulic case drain
tube on the left-hand engine, and on the hydraulic supply tube on the
oil reservoir on the left-hand engine. Chafed hydraulic tubes in the left-hand
engine and consequent hydraulic tube failure and uncontrolled loss of
flammable fluid within the engine cowling, if not corrected, could result
in a fire in the engine nacelle and loss of control of the airplane.
Relevant Service Information
We reviewed the following service bulletins:
Bombardier Alert Service Bulletin A45-29-15, dated December 26, 2006.
Bombardier Alert Service Bulletin A40-29-03, dated December 26, 2006.
The service bulletins describe procedures for a detailed inspection for
chafing and other damage of the case drain tube from the hydraulic pump
case installed on the left-hand engine. The service bulletins also describe
procedures for repositioning any tube that has damage within certain limits
and replacing any tube that has damage that exceeds those limits.
We have reviewed the following temporary revisions (TRs):
Learjet 40 Temporary Revision (TR) 71-1, dated April 28, 2009, to the
Learjet 40 Maintenance Manual MM-105.
Learjet 45 TR 71-1, dated April 28, 2009, to the Learjet 45 Maintenance
Manual MM-104.
The TRs describe procedures for repetitive detailed inspections for discrepancies,
including damage to the left engine's nacelle tubing and inadequate clearance
between any unsupported section of the tube or other tubing and surrounding
components. The TRs also describe procedures for adjusting the tubing
and clamping to achieve minimum clearance and replacing any tube that
has damage exceeding certain limits.
We have reviewed the engine--maintenance practices in the following maintenance
manual documents:
Learjet 45 Maintenance Manual MM-104, Revision 47, dated March 30, 2009,
Powerplant-Maintenance Practices Section 71-00-00 and Engine-Maintenance
Practices Section 71-00-01 (for M45 airplanes).
Learjet 40 Maintenance Manual MM-105, Revision 15, dated March 30, 2009,
Engine-Maintenance Practices Section 71-00-01 (for M40 airplanes).
The engine-maintenance practices sections in the maintenance manuals (MMs)
describe procedures for a general visual inspection for evidence of engine
oil, hydraulic fluid, or fuel leakage within the left engine accessory
compartment. For airplanes on which there is evidence of leakage, the
MMs describe procedures for removing each plumbing clamp within the area
affected by the service bulletins and MM TRs identified in this AD, and
cleaning and removing all evidence of fluid leakage. Tubing clamps that
are associated with inadequate clearance are replaced with new clamps.
FAA's Determination and Requirements of This AD
We are issuing this AD because we evaluated all the relevant information
and determined the unsafe condition described previously is likely to
exist or develop in other products of the same type design. This AD requires
accomplishing the actions specified in the service information described
previously, except as discussed below.
Differences Between the AD and the Service Information
Although the service bulletins provide for one-time inspections, this
AD requires that those inspections be repeated, until a terminating action
can be accomplished to adequately address the identified unsafe condition.
This difference has been coordinated with the manufacturer.
Interim Action
We consider this AD interim action. The manufacturer is currently developing
a modification that will address the unsafe condition identified in this
AD. Once this modification is developed, approved, and available, we might
consider additional rulemaking.
FAA's Justification and Determination of the Effective Date
Chafed hydraulic tubes in the left-hand engine and consequent hydraulic
tube failure and uncontrolled loss of flammable fluid within the engine
cowling could result in a fire in the engine nacelle and loss of control
of the airplane. Because of our requirement to promote safe flight of
civil aircraft and thus the critical need to ensure the proper functioning
of the affected systems, and because of the short compliance time involved
with this action, this AD must be issued immediately.
Because an unsafe condition exists that requires the immediate adoption
of this AD, we find that notice and opportunity for prior public comment
hereon are impracticable and that good cause exists for making this amendment
effective in less than 30 days.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety,
and we did not provide you with notice and an opportunity to provide your
comments before it becomes effective. However, we invite you to send any
written data, views, or arguments about this AD. Send your comments to
an address listed under the ADDRESSES section. Include "Docket No. FAA-2009-0498;
Directorate Identifier 2009-NM-065-AD'' at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic, environmental,
and energy aspects of this AD. We will consider all comments received
by the closing date and may amend this 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 AD.
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
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.
You can find our regulatory evaluation and the estimated costs of compliance
in the AD Docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference,
Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 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:
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