
[Federal Register: August 27, 2009 (Volume 74, Number 165)]
[Proposed Rules]               
[Page 43645-43647]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr27au09-23]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0719; Directorate Identifier 2009-NM-078-AD]
RIN 2120-AA64

 
Airworthiness Directives; Learjet 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 
certain Learjet Model 45 airplanes. This proposed AD would require 
inspecting the baggage bay door fire barrier seal for inconel mesh in 
the fire barrier seal material; for certain airplanes, inspecting the 
fiberglass doublers for presence of red Room Temperature Vulcanizing 
(RTV) sealant; and doing related investigative and corrective actions 
if necessary. This proposed AD results from reports of incorrect 
external baggage door seal material and door seal sealant as well as 
incorrect sealant on interior baggage panels used during manufacture of 
the airplane. We are proposing this AD to prevent the use of door seals 
and sealant that do not meet flammability requirements, which could 
result in an uncontrollable and undetected fire within the baggage 
compartment.

DATES: We must receive comments on this proposed AD by October 13, 
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 proposed 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. 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 or 
425-227-1152.

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: William Griffith, Aerospace Engineer, 
Airframe Branch, ACE-118W, FAA, Wichita Aircraft Certification Office, 
1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 
67209; telephone (316) 946-4116; fax (316) 946-4107.

SUPPLEMENTARY INFORMATION: 

[[Page 43646]]

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-2009-0719; 
Directorate Identifier 2009-NM-078-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 propose to adopt a new airworthiness directive (AD) for certain 
Learjet Model 45 airplanes. This proposed AD results from reports of 
incorrect external baggage door seal material and door seal sealant as 
well as incorrect sealant on interior baggage panels used during 
manufacture of the airplane. If a fire or heat source deteriorates the 
non-conforming door seal, the flow characteristics of this compartment 
will no longer be maintained, and the fire threat could potentially 
spread to the interior baggage panels. This condition, if not 
corrected, could result in uncontrollable and undetected fire within 
the baggage compartment.

Relevant Service Information

    We have reviewed the service bulletins listed in the following 
table.

                            Service Bulletins
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      Service bulletin           Revision                Dated
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Bombardier Service Bulletin                1  July 21, 2008.
 40-52-07.
Bombardier Service Bulletin                1  July 21, 2008.
 45-52-16.
Bombardier Service Bulletin                1  January 19, 2009.
 40-25-11.
Bombardier Service Bulletin                1  January 19, 2009.
 45-25-21.
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     Bombardier Service Bulletins 40-52-07 and 45-52-16, both Revision 
1, both dated July 21, 2008, describe procedures for inspecting for the 
presence of inconel mesh in the baggage bay door fire barrier seal 
material, and doing related investigative and corrective actions as 
applicable. The corrective actions include replacing the fire barrier 
seal if inconel mesh is not present in the baggage bay door fire 
barrier seal. The related investigative action is inspecting for the 
presence of dark gray firewall sealant used to attach the fire barrier 
seal to the baggage bay door if inconel mesh is present in the fire 
barrier seal, and for airplanes on which there is no dark grey firewall 
sealant, the corrective action is replacing the fire barrier seal.
    Bombardier Service Bulletins 40-25-11 and 45-25-21, both Revision 
1, both dated January 19, 2009, describe procedures for inspecting the 
outer surfaces of the fiberglass doublers for presence of red Room 
Temperature Vulcanizing (RTV) sealant. For airplanes on which there is 
any red RTV sealant found, these service bulletins describe procedures 
for replacing the sealant with a primerless sealant.

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.

Costs of Compliance

    We estimate that this proposed AD would affect 256 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                 Estimated Costs
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                                              Average
            Action              Work hours   labor rate    Cost per      Number of U.S.-         Fleet cost
                                              per hour     product    registered airplanes
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Inspection and modification             10          $80         $800  Up to 256...........  Up to $204,800.
 of red RTV sealant.
Inspection and modification              6           80          480  Up to 256...........  Up to $122,880.
 of fire barrier seal.
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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:

[[Page 43647]]

    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.

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: Docket No. FAA-2009-0719; Directorate Identifier 2009-NM-
078-AD.

Comments Due Date

    (a) We must receive comments by October 13, 2009.

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 inclusive, 45-
323 through 45-332 inclusive, and 45-2001 through 45-2075 inclusive.

Subject

    (d) Air Transport Association (ATA) of America Code 52: Doors, 
and ATA Code 25: Equipment/Furnishings.

Unsafe Condition

    (e) This AD results from reports of incorrect external baggage 
door seal material and door seal sealant, as well as incorrect 
sealant on interior baggage panels used during manufacture of the 
airplane. The Federal Aviation Administration is issuing this AD to 
prevent the use of door seals and sealant that do not meet 
flammability requirements, which could result in an uncontrollable 
and undetected fire within the baggage compartment.

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 of Red Room Temperature Vulcanizing (RTV) Sealant in Aft 
Baggage Bay

    (g) For airplanes having serial numbers 45-005 through 45-314 
inclusive and 45-2001 through 45-2065 inclusive: Within 300 flight 
hours after the effective date of this AD, do a general visual 
inspection of the outer surfaces of the fiberglass doublers for the 
presence of red RTV sealant, in accordance with the Accomplishment 
Instructions in Bombardier Service Bulletin 45-25-21, Revision 1, 
dated January 19, 2009; or 40-25-11, Revision 1, dated January 19, 
2009; as applicable. If any red RTV sealant is found, before further 
flight, replace the sealant in accordance with the Accomplishment 
Instructions in Bombardier Service Bulletin 45-25-21, Revision 1, 
dated January 19, 2009; or 40-25-11, Revision 1, dated January 19, 
2009; as applicable.

    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.''

Inspection of Baggage Bay Door Fire Barrier Seal

    (h) For all airplanes: Within 300 flight hours after the 
effective date of this AD, do a general visual inspection of the 
baggage bay door fire barrier seal for the presence of metal inconel 
mesh in the material, and do all applicable related investigative 
and corrective actions, in accordance with the Accomplishment 
Instructions in Bombardier Service Bulletin 45-52-16, Revision 1, 
dated July 21, 2008; or 40-52-07, Revision 1, dated July 21, 2008; 
as applicable. Do all applicable related investigative and 
corrective actions before further flight in accordance with the 
Accomplishment Instructions in Bombardier Service Bulletin 45-52-16, 
Revision 1, dated July 21, 2008; or 40-52-07, Revision 1, dated July 
21, 2008; as applicable.

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 
using the procedures found in 14 CFR 39.19. Send information to 
ATTN: William Griffith, Aerospace Engineer, Airframe Branch, ACE-
118W, FAA, Wichita ACO, 1801 Airport Road, Room 100, Mid-Continent 
Airport, Wichita, Kansas 67209; telephone (316) 946-4116; 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 August 18, 2009.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-20637 Filed 8-26-09; 8:45 am]

BILLING CODE 4910-13-P
