AD 2017-08-07

We are adopting a new airworthiness directive (AD) for certain Learjet, Inc., Model 60 airplanes. This AD was prompted by an evaluation by the design approval holder (DAH) indicating that the upper fuselage skin under the aft oxygen line fairing is subject to multi-site damage (MSD). This AD requires a one-time inspection of the fuselage skin for corrosion, and related investigative and corrective actions if necessary. We are issuing this AD to address the unsafe condition on these products.

Final rule.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

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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):

2017-08-07 Learjet, Inc.: Amendment 39-18856; Docket No. FAA-2016- 9505; Directorate Identifier 2016-NM-155-AD.

(a) Effective Date

This AD is effective May 22, 2017.

(b) Affected ADs

None.

(c) Applicability

This AD applies to Learjet, Inc., Model 60 airplanes, certificated in any category, serial numbers 60-002 through 60-430 inclusive.

(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

This AD was prompted by an evaluation by the design approval holder indicating that the upper fuselage skin under the aft oxygen line fairing is subject to multi-site damage. We are issuing this AD to detect and correct corrosion of the fuselage skin, which could result in reduced structural integrity of the airplane.

(f) Compliance

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

(g) Inspection of the Fuselage Skin, and Related Investigative and Corrective Actions

At the applicable time specified in paragraph (g)(1), (g)(2), or (g)(3) of this AD: Do a fluorescent dye penetrant inspection of the fuselage skin between stringers (S)-2L and S-2R for corrosion; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016, except as required by paragraph (h) of this AD. Do all applicable related investigative and corrective actions before further flight.
(1)For airplanes with more than 12 years since the date of issuance of the original airworthiness certificate or the date of issuance of the original export certificate of airworthiness as of the effective date of this AD: Within 12 months after the effective date of this AD.
(2) For airplanes with more than 6 years but equal to or less than 12 years since the date of issuance of the original airworthiness certificate or the date of issuance of the original export certificate of airworthiness as of the effective date of this AD: Within 24 months after the effective date of this AD.
(3) For airplanes with 6 years or less since the date of issuance of the original airworthiness certificate or the date of issuance of the original export certificate of airworthiness as of the effective date of this AD: Within 36 months after the effective date of this AD.

(h) Service Information Exception

Where Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016, specifiescontacting Learjet, Inc., for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD.

(i) Reporting

At the applicable time specified in paragraph (i)(1) or (i)(2) of this AD: Submit a report of the findings (both positive and negative) of the inspection required by the introductory text of paragraph (g) of this AD to: Wichita-COS@faa.gov; or Ann Johnson, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Wichita, KS 67209. The report must include the name of the owner, the address of the owner, the name of the organization incorporating Learjet 60 Service Bulletin 60-53-19, the date that inspection was completed, the name of the person submitting the report, the address, telephone number, and email of the person submitting the report, the airplane serial number, the total time (flight hours) on the airplane, the total number of landings on the airplane, whether corrosionwas detected, whether corrosion was repaired, the structural repair manual (SRM) chapter and revision used (if repaired), and whether corrosion exceeded the minimum thickness specified in Learjet 60 Service Bulletin 60-53-19 (and specify the SRM chapter and revision, if used as an aid to determine minimum thickness).
(1) If the inspection was done on or after the effective date of this AD: Submit the report within 30 days after the inspection.
(2) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

(j) Credit for Previous Actions

This paragraph provides credit for the actions specified in the introductory text to paragraph (g) of this AD, if those actions were performed before the effective date of this AD using Learjet 60 Service Bulletin 60-53-19, dated November 23, 2015; Learjet 60 Service Bulletin 60-53-19, Revision 1, dated April 4, 2016; or Learjet 60 Service Bulletin 60-53-19, Revision 2, dated April 18, 2016.

(k) Paperwork Reduction Act Burden Statement

A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at: 800 Independence Ave. SW., Washington, DC 20591, Attn: Information Collection Clearance Officer, AES-200.

(l) 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 (m)(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.
(3) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by a Learjet, Inc., Designated Engineering Representative (DER), or a Unit Member (UM) of the Learjet Organization Designation Authorization (ODA), that has been authorized by the Manager, Wichita ACO, to make those findings. To be approved, the repair, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

(m) Related Information

(1) For more information about this AD, contact Paul Chapman, Aerospace Engineer, Airframe Branch, ACE-118W, FAA, Wichita ACO, 1801 Airport Road, Room 100, Dwight D. Eisenhower Airport, Wichita, KS 67209; phone: 316-946-4152; fax: 316-946-4107; email: Wichita-COS@faa.gov.
(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (n)(3) and (n)(4) of this AD.

(n) 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) Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016.
(ii) Reserved.
(3) For Learjet, Inc., 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 the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.

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(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.

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 60 airplanes. The NPRM published in the Federal Register on December 20, 2016 (81 FR 92745) (``the NPRM''). The NPRM was prompted by an evaluation by the DAH indicating that the upper fuselage skin under the aft oxygen line fairing is subject to MSD. The NPRM proposed to require a one-time inspection of the fuselage skin for corrosion, and related investigative and corrective actions if necessary. We are issuing this AD to detect and correct corrosion of the fuselage skin, which could result in reduced structural integrity of the airplane.

Comments

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

Request To Require Repetitive Inspections

An anonymous commenter stated that given the cause is unknown, a one-time inspection is insufficient to protect against corrosion. The commenter stated

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that we should require more frequent inspections.
We partially agree with the commenter. We understand the concern that repetitive inspections might be necessary to reduce the damage caused by corrosion. However, the required inspection is considered to be interim action, and in order to establish meaningful inspection intervals without causing excessive expense to operators, this AD requires owners/operators to report the extent of corrosion on their airplanes along with the total time (i.e., flight hours) and total number of landings on the airplanes. Using this information, the FAA will be able to gain a better understanding of the damage to the fleet. This will allow us to determine if additional corrective action is needed and what the appropriate action should be. It also will provide justification as to whether or not further rulemaking is needed. We have not changed this AD in this regard.

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 for correcting 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 Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016. The service information describes procedures for inspections of the fuselage crown skin for corrosion, and related investigative and corrective actions if necessary. 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.

Interim Action

We consider this AD interim action. Because the cause of the corrosion is not known, the inspection reports will help determine the extent of the corrosion in the affected fleet. Based on the results of these reports, we might determine that further corrective action is warranted. Once further corrective action has been identified, we might consider further rulemaking.

Costs of Compliance

We estimate that this AD affects 284 airplanes of U.S. registry. We estimate the following costs to comply with this AD:

Estimated Costs ----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Inspections........................ 46 work-hoursx $85 per $265 $4,175 $1,185,700
hour = $3,910. Reporting.......................... 1 work-hour x $85 per hour 0 85 24,140
= $85. ----------------------------------------------------------------------------------------------------------------

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this AD.
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.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB control number. The control number for the collection of information required by this AD is 2120- 0056. The paperwork cost associated with this AD has been detailed in the Costs of Compliance section of this document and includes time for reviewing instructions, as well as completing and reviewing the collection of information. Therefore, all reporting associated with this AD is mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at 800 Independence Ave. SW., Washington, DC 20591, ATTN: Information Collection Clearance Officer, AES-200.

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 regulatoryaction'' 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.