Document ID: FAA-2014-0010-0004
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Learjet Inc. Airplanes
Posted Date: 2014-07-15T04:00Z

[Federal Register Volume 79, Number 135 (Tuesday, July 15, 2014)]
[Rules and Regulations]
[Pages 41085-41087]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-15377]

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  Federal Register / Vol. 79, No. 135 / Tuesday, July 15, 2014 / Rules 
and Regulations  

[[Page 41085]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2014-0010; Directorate Identifier 2012-NM-218-AD; 
Amendment 39-17882; AD 2014-13-06]
RIN 2120-AA64

Airworthiness Directives; Learjet Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Learjet Inc. Model 45 airplanes. This AD was prompted by a report of 
two cases of premature corrosion found on the structural support flange 
for the engine thrust reverser. This AD requires inspecting for any 
corrosion, and damage to the sealant; installing sealants and gaskets; 
and related investigative and corrective actions as necessary. We are 
issuing this AD to prevent failure of the thrust reverser structural 
support, which could result in departure of the thrust reverser from 
the engine that could subsequently result in damage to the adjacent 
support structure and engine controls, airframe structure, and control 
surfaces. Departing thrust reversers could also result in injury to 
persons on the ground.

DATES: This AD is effective August 19, 2014.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of August 19, 
2014.

ADDRESSES: For service information identified in this AD, contact 
Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone 316-
946-2000; fax 316-946-2220; email ac.ict@aero.bombardier.com; Internet 
http://www.bombardier.com. You may view this referenced service 
information at the FAA, Transport Airplane Directorate; 1601 Lind 
Avenue SW., Renton, WA 98057-3356. 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 by searching for and locating Docket No. FAA-2014-
0010; 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 (phone: 800-647-
5527) is Docket 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: Paul Chapman, Aerospace Engineer, 
Airframe and Services Branch, ACE-118W, FAA, Wichita Aircraft 
Certification Office, 1801 Airport Road, Room 100, Mid-Continent 
Airport, Wichita, KS 67209; phone: 316-946-4152; fax: 316-946-4107; 
email: paul.chapman@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to certain Learjet Inc. Model 
45 airplanes. The NPRM published in the Federal Register on February 
10, 2014 (79 FR 7601). The NPRM was prompted by a report of two cases 
of premature corrosion found on the structural support flange for the 
engine thrust reverser that attaches the thrust reverser to the engine. 
The thrust reverser's attach flange is made of aluminum and the 
corrosion of that flange can be caused by contact with exposed graphite 
fibers from the engine's composite bypass duct. The NPRM proposed to 
require doing a fluorescent penetrant inspection of the metallic 
components of the thrust reverser's attach flange for any corrosion; 
inspecting the thrust reverser flange for damage to the sealant, as 
applicable; installing sealants and gaskets, as applicable, to the 
thrust reverser flanges and service island flanges; and related 
investigative and corrective actions as necessary. We are issuing this 
AD to prevent failure of the thrust reverser structural support, which 
could result in departure of the thrust reverser from the engine that 
could subsequently result in damage to the adjacent support structure 
and engine controls, airframe structure, and control surfaces. 
Departing thrust reversers could also result in injury to persons on 
the ground.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
and the FAA's response to each comment.

Request To Add Service Information to Paragraph (i) of This AD

    Bombardier requested that paragraph (i) of the proposed AD (79 FR 
1601, February 10, 2014) be revised to add Bombardier Service Bulletin 
40-78-03, Revision 1, dated November 5, 2012; or Bombardier Service 
Bulletin 45-78-9, Revision 1, dated November 5, 2012. Bombardier stated 
that adding this service information to paragraph (i) of the proposed 
AD would allow credit for accomplishing the requirements of paragraph 
(g) of the proposed AD before the effective date of the AD.
    We disagree with revising paragraph (i) of this AD. The purpose of 
paragraph (i) of this AD is to allow credit for using an earlier 
revision of the required service information before the effective date 
of the AD if that earlier revision is considered acceptable for 
addressing the unsafe condition. If actions required by paragraph (g) 
of this AD were accomplished before the effective date of the AD, using 
the service information required by paragraph (g) of this AD, those 
actions are considered acceptable for compliance, since paragraph (f) 
of this AD states ``Comply with this AD within the compliance times 
specified, unless already done.'' We have not changed this AD in this 
regard.

Clarification of Marketing Designation

    We have revised Note 1 to paragraph (c) of this AD to clarify the 
marketing designations that Model 45 airplanes might be known as.

[[Page 41086]]

Conclusion

    We reviewed the relevant data, considered the comment received, and 
determined that air safety and the public interest require adopting 
this AD as proposed except for minor editorial changes. We have 
determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM (79 FR 1601, February 10, 2014) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (79 FR 1601, February 10, 2014).

Costs of Compliance

    We estimate that this AD affects 365 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                 Number of U.S.         Cost on U.S.
              Action                        Labor cost                Parts cost          Cost per product          products              operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspections and installing          Between 26 and 36 work-     Between $1,216 and     Between $3,426 and     730 thrust reversers  Between $2,500,980
 sealants and gaskets.               hours x $85 per hour =      $1,476 per thrust      $4,536 per thrust      (365 airplanes).      and $3,311,280.
                                     Between $2,210 and $3,060   reverser.              reverser.
                                     per thrust reverser.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary replacements 
that would be required based on the results of the inspection. We have 
no way of determining the number of aircraft that might need this 
replacement.

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
            Action                    Labor cost            Parts cost                Cost per product
----------------------------------------------------------------------------------------------------------------
Replacing thrust reverser       40 work-hours x $85     $1,200 per thrust  $4,600 per thrust reverser.
 attachment flange.              per hour = $3,400 per   reverser.
                                 thrust reverser.
----------------------------------------------------------------------------------------------------------------

    According to the manufacturer, some of the costs of this AD may be 
covered under warranty, thereby reducing the cost impact on affected 
individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.

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),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

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

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 FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2014-13-06 Learjet Inc.: Amendment 39-17882; Docket No. FAA-2014-
0010; Directorate Identifier 2012-NM-218-AD.

(a) Effective Date

    This AD is effective August 19, 2014.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Learjet Inc. Model 45 airplanes having serial 
numbers (S/Ns) 45-005 through 45-436 inclusive, and 45-2001 through 
45-2132 inclusive, certificated in any category, that are equipped 
with composite engine fan bypass ducts.

    Note 1 to paragraph (c) of this AD: Learjet Model 45 airplanes 
having S/Ns 45-2001 and subsequent are commonly referred to as 
``Model 40'' airplanes or Learjet 40 airplanes as marketing 
designations.

(d) Subject

    Air Transport Association (ATA) of America Code 78, Engine 
Exhaust.

(e) Unsafe Condition

    This AD was prompted by a report of two cases of premature 
corrosion found on the structural support flange for the engine 
thrust reverser. We are issuing this AD to prevent failure of the 
thrust reverser structural support, which could result in departure 
of the thrust reverser from the engine that could subsequently 
result in damage to the adjacent support structure and engine 
controls, airframe structure, and control surfaces.

[[Page 41087]]

Departing thrust reversers could also result in injury to persons on 
the ground.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Inspections and Sealant Installation With Applicable Related 
Investigative and Corrective Actions

    Within 1,200 flight hours or 48 months after the effective date 
of this AD, whichever occurs first, do the requirements of paragraph 
(g)(1) of this AD; and for the airplanes identified in paragraph 
(g)(2) of this AD, do the requirements of paragraph (g)(2) of this 
AD concurrently.
    (1) Do a detailed inspection of the thrust reverser flange for 
damage to the sealant, as applicable, and install sealants and 
gaskets before further flight, as applicable, to the thrust reverser 
flanges and service island flanges, in accordance with the 
Accomplishment Instructions of Bombardier Service Bulletin 40-78-03, 
Revision 1, dated November 5, 2012 (for Model 45 airplanes having S/
Ns 45-2001 through 45-2132 inclusive); or Bombardier Service 
Bulletin 45-78-9, Revision 1, dated November 5, 2012 (for Model 45 
airplanes having S/Ns 45-005 through 45-436 inclusive).
    (2) For Model 45 airplanes having S/Ns 45-2001 through 45-2129 
inclusive and S/Ns 45-005 through 45-420 inclusive: Do a fluorescent 
penetrant inspection for corrosion of the metallic components of the 
thrust reverser's attach flange for any corrosion, and all 
applicable related investigative and corrective actions, in 
accordance with the Accomplishment Instructions of Nordam Service 
Bulletin 5045 78-13, dated January 17, 2012, except as required by 
paragraph (h) of this AD. Do all applicable related investigative 
and corrective actions before further flight.

(h) Exception to the Nordam Service Information

    If any material thickness less than the minimum allowable 
thickness is found during any inspection required by paragraph 
(g)(2) of this AD, and Nordam Service Bulletin 5045 78-13, dated 
January 17, 2012, specifies contacting Bombardier Learjet for 
appropriate action: Before further flight, repair the thrust 
reverser's attach flange in accordance with a method approved by the 
Manager, Wichita Aircraft Certification Office (ACO), FAA. For a 
repair method to be approved by the Manager, Wichita ACO, as 
required by this paragraph, the Manager's approval letter must 
specifically refer to this AD.

(i) Credit for Previous Actions

    This paragraph provides credit for the actions specified in 
paragraph (g) of this AD, if those actions were performed before the 
effective date of this AD using Bombardier Service Bulletin 40-78-
03, dated February 27, 2012 (for Model 45 airplanes having S/Ns 45-
2001 through 45-2132); or Bombardier Service Bulletin 45-78-9, dated 
February 27, 2012 (for Model 45 airplanes having S/Ns 45-005 through 
45-436).

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Wichita ACO, FAA, has the authority to approve 
AMOCs for this AD, if requested using the procedures found in 14 CFR 
39.19. In accordance with 14 CFR 39.19, send your request to your 
principal inspector or local Flight Standards District Office, as 
appropriate. If sending information directly to the manager of the 
ACO, send it to the attention of the person identified in paragraph 
(k)(1) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Related Information

    (1) For more information about this AD, contact Paul Chapman, 
Aerospace Engineer, Airframe and Services Branch, ACE-118W, FAA, 
Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, 
Mid-Continent Airport, Wichita, KS 67209; phone: 316-946-4152; fax: 
316-946-4107; email: paul.chapman@faa.gov.
    (2) Service information identified in this AD that is not 
incorporated by reference may be viewed at the addresses specified 
in paragraphs (l)(3) and (l)(4) of this AD.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Bombardier Service Bulletin 40-78-03, Revision 1, dated 
November 5, 2012.
    (ii) Bombardier Service Bulletin 45-78-9, Revision 1, dated 
November 5, 2012.
    (iii) Nordam Service Bulletin 5045 78-13, dated January 17, 
2012.
    (3) For Learjet and Nordam service information identified in 
this AD, contact Learjet, Inc., One Learjet Way, Wichita, KS 67209-
2942; telephone 316-946-2000; fax 316-946-2220; email 
ac.ict@aero.bombardier.com; Internet http://www.bombardier.com.
    (4) You may view this service information at FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, WA 98057-3356. 
For information on the availability of this material at the FAA, 
call 425-227-1221.
    (5) You may view this service information that is incorporated 
by reference 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 June 19, 2014.
Michael J. Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2014-15377 Filed 7-14-14; 8:45 am]
BILLING CODE 4910-13-P