Document ID: FAA-2018-0327-0003
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Learjet, Inc. Airplanes
Posted Date: 2018-09-18T04:00Z

[Federal Register Volume 83, Number 181 (Tuesday, September 18, 2018)]
[Rules and Regulations]
[Pages 47044-47047]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-19853]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0327; Product Identifier 2018-CE-001-AD; Amendment 
39-19404; AD 2018-19-04]
RIN 2120-AA64

Airworthiness Directives; Learjet, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Learjet, Inc. Models 28, 29, 31, 31A, 35, 35A, 36, 36A, 55, 55B, 55C, 
and 60 airplanes. This AD was prompted by fatigue cracks initiating in 
the flap support structure due to repetitive flap loads, which has 
caused flap nose roller support bracket failure. This AD requires 
replacement of the flap nose roller fitting, nose roller support 
bracket, and adjacent rib support structure with improved components. 
We are issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective October 23, 2018.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of October 23, 
2018.

ADDRESSES: For service information identified in this final rule, 
contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209; 
telephone: 316-946-2000; email: [email protected]; internet: 
https://www.bombardier.com. You may view this service information at 
the FAA, Policy and Innovation Division, 901 Locust, Kansas City, 
Missouri 64106. For information on the availability of this material at 
the FAA, call (816) 329-4148. It is also available on the internet at 
http://www.regulations.gov by searching for and locating Docket No. 
FAA-2018-0327.

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-2018-
0327; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this final rule, the regulatory evaluation, any comments received, and 
other information. The address for Docket Operations (phone: 800-647-
5527) is

[[Page 47045]]

Docket Operations, 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: Tara Shawn, Aerospace Engineer, 
Wichita ACO Branch, 1801 Airport Road, Room 100, Wichita, Kansas 67209; 
telephone: (316) 946-4141; fax: (316) 946-4107; email: 
[email protected] or [email protected].

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. 
Models 28, 29, 31, 31A, 35, 35A, 36, 36A, 55, 55B, 55C, and 60 
airplanes. The NPRM published in the Federal Register on May 8, 2018 
(83 FR 20740). The NPRM was prompted by a report that a skewed flap and 
aileron became bound on a Model 31A airplane, which was later found to 
have fatigue cracks in the flap support structure due to repetitive 
flap loads. Fatigue cracks in the flap support structure caused by 
repetitive flap loads can result in failure of the flap nose roller 
support bracket. Repetitive flap loads occur on all models identified 
by this AD. The NPRM proposed to require replacement of the flap nose 
roller fitting, nose roller support bracket, and adjacent rib support 
structure with improved components. This condition, if not addressed, 
could result in loss of roll control on approach with consequent loss 
of control of the airplane. We are issuing this AD to address the 
unsafe condition on these products.

Comments

    We gave the public the opportunity to participate in developing 
this final rule. We received no comments on the NPRM or on the 
determination of the cost to the public.

Clarification of Repair Method

    We have revised this action to clarify that operators are not 
required to obtain repair instructions from Learjet. Instead, operators 
must use a repair method approved by the Manager, Wichita ACO Branch, 
FAA.

Conclusion

    We reviewed the relevant data and determined that air safety and 
the public interest require adopting this final rule as proposed except 
for the changes described previously and other minor editorial changes. 
We have determined that these changes:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

    We reviewed Bombardier Learjet 28/29 Service Bulletin SB 28/29-27-
31 Recommended, dated September 11, 2017; Bombardier Learjet 31 SB 31-
27-35 Recommended, dated September 11, 2017; Bombardier Learjet 35/36 
SB 35/36-27-50 Recommended, dated September 11, 2017; Bombardier 
Learjet 55 SB 55-27-41 Recommended, dated September 11, 2017; and 
Bombardier Learjet 60 SB 60-27-39 Recommended, Revision 1, dated 
January 15, 2018. For the applicable models, the service information 
describes procedures for replacement of the flap nose roller fitting, 
nose roller support bracket, and adjacent rib support structure with 
improved components. The service information also contains instructions 
to ensure correct flap alignment. This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section.

Costs of Compliance

    We estimate that this AD affects 706 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost          Parts cost *       product        operators
----------------------------------------------------------------------------------------------------------------
Replacement of flap nose roller         188 work-hours x $85 per         $12,213         $28,193     $19,904,258
 fitting, nose roller support bracket,   hour = $15,980.
 and adjacent rib support structure
 with improved components.
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* Parts cost is an average of the combined costs for replacement of all of the kits per airplane. Not all
  airplanes will need all kits, as credit is allowed for some previous installations.

                         Individual Parts Cost *
------------------------------------------------------------------------
                       Kit Number (K/N)                        Part cost
------------------------------------------------------------------------
K/N 2381000-802..............................................       $827
K/N 2381000-804..............................................        822
K/N 2381000-806..............................................        780
K/N 2381000-808..............................................        793
K/N 2381000-809..............................................      1,358
K/N 2381000-810..............................................      1,358
K/N 2381000-811..............................................      1,822
K/N 2381000-817..............................................      1,674
K/N 2381000-818..............................................      1,432
K/N 2381000-819..............................................      1,415
K/N 2381000-820..............................................      1,912
K/N 2381000-821..............................................      1,912
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* Parts required for replacement may vary for different models and
  different airplanes.

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.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to small airplanes, gliders, 
balloons, airships, domestic business jet transport airplanes, and 
associated

[[Page 47046]]

appliances to the Director of the Policy and Innovation Division.

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):

2018-19-04 Learjet, Inc.: Amendment 39-19404; Docket No. FAA-2018-
0327; Product Identifier 2018-CE-001-AD.

(a) Effective Date

    This AD is effective October 23, 2018.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to the Learjet, Inc. model airplanes that 
are certificated in any category, as listed in table 1 to paragraph 
(c) of this AD.
[GRAPHIC] [TIFF OMITTED] TR18SE18.000

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 2750, TE Flap Control System.

(e) Unsafe Condition

    This AD was prompted by reports of fatigue cracks initiating in 
the flap support structure due to repetitive flap loads. We are 
issuing this AD to require replacement of the flap nose roller 
fitting, nose roller support bracket, and adjacent rib support 
structure with improved components. The unsafe condition, if not 
addressed, could cause failure of the flap nose roller support 
bracket and lead to loss of roll control on approach with consequent 
loss of control of the airplane.

(f) Compliance

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

(g) Corrective Action

    (1) For Models 28 and 29 airplanes:
    (i) Within 24 months after October 23, 2018 (the effective date 
of this AD) or within 400 landings after October 23, 2018 (the 
effective date of this AD), whichever occurs first, replace the nose 
roller fitting, nose roller support bracket, and adjacent rib 
support structure with replacement parts by following the 
Accomplishment Instructions in Bombardier Learjet 28/29 Service 
Bulletin SB 28/29-27-31 Recommended, dated September 11, 2017.
    (ii) Although Paragraph 3.B.(1) of the applicable SB for these 
models that have modified flap roller assemblies requires the 
operator to contact Learjet Inc. for repair instructions, this AD 
requires that you do the repair using a method approved by the 
Manager, Wichita ACO Branch, FAA. For a repair method to be approved 
by the Manager, Wichita ACO Branch, as required by this paragraph, 
the Manager's approval letter must specifically refer to this AD.
    (2) For Models 31 and 31A airplanes: Within 24 months after 
October 23, 2018 (the effective date of this AD) or within 400 
landings after October 23, 2018 (the effective date of this AD), 
whichever occurs first, replace the nose roller fitting, nose roller 
support bracket, and adjacent rib support structure with replacement 
parts by following the Accomplishment Instructions in Bombardier 
Learjet 31 SB 31-27-35 Recommended, dated September 11, 2017.

[[Page 47047]]

    (3) For Models 35, 35A, 36, and 36A airplanes: Within 24 months 
after October 23, 2018 (the effective date of this AD) or within 400 
landings after October 23, 2018 (the effective date of this AD), 
whichever occurs first, replace the nose roller fitting, nose roller 
support bracket, and adjacent rib support structure with replacement 
parts by following the Accomplishment Instructions in Bombardier 
Learjet 35/36 SB 35/36-27-50 Recommended, dated September 11, 2017.
    (4) For Models 55, 55B, and 55C airplanes: Within 24 months 
after October 23, 2018 (the effective date of this AD) or within 400 
landings after October 23, 2018 (the effective date of this AD), 
whichever occurs first, replace the nose roller fitting, nose roller 
support bracket, and adjacent rib support structure with replacement 
parts by following the Accomplishment Instructions in Bombardier 
Learjet 55 SB 55-27-41 Recommended, dated September 11, 2017.
    (5) For Model 60 airplanes: Within 12 months after October 23, 
2018 (the effective date of this AD) or within 200 landings after 
October 23, 2018 (the effective date of this AD), whichever occurs 
first, replace the nose roller fitting, nose roller support bracket, 
and adjacent rib support structure with replacement parts by 
following the Accomplishment Instructions in Bombardier Learjet 60 
SB 60-27-39 Recommended, Revision 1, dated January 15, 2018.
    (6) For all airplanes: Some compliance times in this AD are 
presented in landings. If you do not keep a record of the total 
number of landings, then use a 1-to-1 conversion for hours time-in-
service (TIS) to landings. Example: 20 hours TIS = 20 landings.
    (7) For Models 31, 31A, 35, 35A, 36, 36A, 55, 55B, 55C, and 60 
airplanes: Although Paragraph 3.B.(2) of the applicable SB for these 
models that have modified flap roller assemblies requires the 
operator to contact Learjet Inc. for repair instructions, this AD 
requires you do the repair using a method approved by the Manager, 
Wichita ACO Branch, FAA. For a repair method to be approved by the 
Manager, Wichita ACO Branch, as required by this paragraph, the 
Manager's approval letter must specifically refer to this AD.

(h) Credit for Previous Actions

    For Model 60 airplanes: This AD allows credit for actions 
required in paragraph (g)(5) of this AD if done before the effective 
date of this AD following Bombardier Learjet 60 SB 60-27-39 
Recommended, Basic Issue, dated September 11, 2017.

(i) No Reporting Requirement

    Although Bombardier Learjet 28/29 SB 28/29-27-31 Recommended, 
dated September 11, 2017; Bombardier Learjet 31 SB 31-27-35 
Recommended, dated September 11, 2017; Bombardier Learjet 35/36 SB 
35/36 -27-50 Recommended, dated September 11, 2017; Bombardier 
Learjet 55 SB 55-27-41 Recommended, dated September 11, 2017; and 
Bombardier Learjet 60 SB 60-27-39 Recommended, Revision 1, dated 
January 15, 2018, all specify to submit a compliance response form 
to the manufacturer per paragraph 3.E., this AD does not require 
that action.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Wichita ACO branch, 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 certification office, 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

    For more information about this AD, contact Tara Shawn, 
Aerospace Engineer, Wichita ACO Branch, 1801 Airport Road, Room 100, 
Wichita, Kansas 67209; telephone: (316) 946-4141; fax: (316) 946-
4107; email: [email protected] or [email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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 Learjet 28/29 Service Bulletin (SB) 28/29-27-31 
Recommended, dated September 11, 2017;
    (ii) Bombardier Learjet 31 SB 31-27-35 Recommended, dated 
September 11, 2017;
    (iii) Bombardier Learjet 35/36 SB 35/36 -27-50 Recommended, 
dated September 11, 2017;
    (iv) Bombardier Learjet 55 SB 55-27-41 Recommended, dated 
September 11, 2017; and
    (v) Bombardier Learjet 60 SB 60-27-39 Recommended, Revision 1, 
dated January 15, 2018.
    (3) For service information identified in this AD, contact 
Learjet, Inc., One Learjet Way, Wichita, Kansas 67209; telephone: 
316-946-2000; email: [email protected]; internet: https://www.bombardier.com.
    (4) You may view this service information at the FAA, Policy and 
Innovation Division, 901 Locust, Kansas City, Missouri 64106. For 
information on the availability of this material at the FAA, call 
(816) 329-4148. In addition, you can access this service information 
on the internet at http://www.regulations.gov by searching for and 
locating Docket No. FAA-2017-1078.
    (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 Kansas City, Missouri, on August 31, 2018.
Melvin J. Johnson,
Deputy Director, Policy & Innovation Division, Aircraft Certification 
Service.
[FR Doc. 2018-19853 Filed 9-17-18; 8:45 am]
 BILLING CODE 4910-13-P