AD 2017-11-09

We are superseding Airworthiness Directive (AD) 2017-08-07 for certain Learjet, Inc., Model 60 airplanes. AD 2017-08-07 required a one-time inspection of the fuselage skin for corrosion, and related investigative and corrective actions if necessary. This new AD retains the actions of AD 2017-08-07 and removes certain airplanes from the applicability. This AD was prompted by a determination that only certain airplanes are affected by the unsafe condition. We are issuing this AD to address the unsafe condition on these products.

Final rule; request for comments.

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 removing Airworthiness Directive (AD) 2017-08-07, Amendment 39-18856 (82 FR 18084, April 17, 2017), and adding the following new AD:

2017-11-09 Learjet, Inc.: Amendment 39-18908; Docket No. FAA-2017- 0501; Directorate Identifier 2017-NM-053-AD.

(a) Effective Date

This AD is effective May 30, 2017.

(b) Affected ADs

This AD replaces AD 2017-08-07, Amendment 39-18856 (82 FR 18084, April 17, 2017) (``AD 2017-08-07'').

(c) Applicability

This AD applies to Learjet, Inc., Model 60 airplanes, certificated in any category, having serial numbers 60-002 through 60-430 inclusive, and having a configuration identified in paragraph (c)(1) or (c)(2) of this AD.
(1) Airplanes with a dorsal-mounted oxygen bottle.
(2) Airplanes that have had the dorsal-mounted oxygen bottle removed but have retained the oxygen line fairing installed on top of the fuselage.

(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) Retained Inspection of the Fuselage Skin, and Related Investigative and Corrective Actions, With No Changes

This paragraph restates the requirements of paragraph (g) ofAD 2017-08-07, with no changes. 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 May 22, 2017 (the effective date of AD 2017-08-07): Within 12 months after May 22, 2017.
(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 May 22, 2017 (the effective date of AD 2017-08-07): Within 24 months after May 22, 2017.
(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 May 22, 2017 (the effective date of AD 2017-08-07): Within 36 months after May 22, 2017.

(h) Retained Service Information Exception, With No Changes

This paragraph restates the requirements of paragraph (h) of AD 2017-08-07, with no changes. Where Learjet 60 Service Bulletin 60- 53-19, Revision 3, dated August 29, 2016, specifies contacting 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) Retained Reporting, With No Changes

This paragraph restates the requirements of paragraph (i) of AD 2017-08-07,with no changes. 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 corrosion was detected, whether corrosion was repaired, the structural repair manual (SRM) chapter and revision used (if repaired), and whether corrosion exceeded the minimum thickness specifiedin 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 May 22, 2017 (the effective date of AD 2017-08-07): Submit the report within 30 days after the inspection.
(2) If the inspection was done before May 22, 2017 (the effective date of AD 2017-08-07): Submit the report within 30 days after May 22, 2017.

(j) Retained Credit for Previous Actions, With No Changes

This paragraph restates the credit provided in paragraph (j) of AD 2017-08-07, with no

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changes. This paragraph provides credit for the actions specified in the introductory text to paragraph (g) of this AD, if those actions were performed before May 22, 2017 (the effective date of AD 2017- 08-07), 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 beenauthorized 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.
(4) AMOCs approved previously for AD 2017-08-07 are approved as AMOCs for the corresponding provisions of 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)(4) and (n)(5) 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.
(3) The following service information was approved for IBR on May 22, 2017 (82 FR 18084, April 17, 2017).
(i) Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016.
(ii) Reserved.
(4) 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.
(5) 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.
(6) 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

On April 7, 2017, we issued AD 2017-08-07, Amendment 39-18856 (82 FR 18084, April 17, 2017) (``AD 2017-08-07''), for Learjet, Inc., Model 60 airplanes, serial numbers 60-002 through 60-430 inclusive. AD 2017- 08-07 required a one-time inspection of the fuselage skin for corrosion, and related investigative and corrective actions if necessary. AD 2017-08-07 resulted from 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). We issued AD 2017-08-07 to detect and correct corrosion of the fuselage skin, which could result in reduced structural integrity of the airplane.

Actions Since AD 2017-08-07 Was Issued

Since we issued AD 2017-08-07, we determined that only certain airplanes identified in the applicability of AD 2017-08-07 are affected by the unsafe condition. For Learjet, Inc., Model 60 airplanes, serial numbers 60-002 through 60-430 inclusive, the unsafe condition affects only airplanes with a dorsal-mounted oxygen bottle and

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airplanes that have had the dorsal-mounted oxygen bottle removed but have retained the oxygen line fairing installed on top of the fuselage. These airplanes are identified in the effectivity of Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016, which is the appropriate source of service information for accomplishing the actions required by AD 2017-08-07. Therefore, we have revised paragraph (c) of this AD to identify only those airplanes affected by the unsafe condition.

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 becausethe interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

FAA's Determination

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.

AD Requirements

This AD requires a one-time inspection of the fuselage skin for corrosion, and related investigative and corrective actions if necessary. This AD also requires sending the inspection results to the FAA.

Differences Between This AD and the Service Information

Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016, specifies to contact the manufacturer for instructions on how to repair certain conditions, but this AD requires repairing those conditions in one of the following ways:
In accordance with a method that we approve; or
Using data that meet the certificationbasis of the airplane, and that have been approved by a Delegated Engineering Representative (DER) for Learjet Inc., or a Unit Member (UM) of the Learjet Organization Designation Authorization (ODA), whom we have authorized to make those findings.

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.

FAA's Justification and Determination of the Effective Date

We determined that unaffected airplanes were inadvertently included in the applicability of AD 2017-08-07, which applied to Learjet, Inc., Model 60 airplanes, serial numbers 60-002 through 60-430 inclusive. However, only airplanes identified in Learjet 60 Service Bulletin 60- 53-19, Revision 3, dated August 29, 2016, are subject to the identified unsafe condition. The actions required by this AD are not required to be done on airplanes that are not identified in Learjet 60 Service Bulletin 60-53-19, Revision 3, dated August 29, 2016. Therefore, we are superseding AD 2017-08-07 to correct the applicability. We find that notice and opportunity for prior public comment are unnecessary 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 was not preceded by notice and an opportunity for public comment. 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 the docket number FAA-2017-0501 and Directorate Identifier 2017-NM-053-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.

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 ---------------------------------------------------------------------------------------------------------------- Inspection (retained action from AD 46 work-hours x $85 per $265 $4,175 $1,185,700
2017[dash]08-07). hour = $3,910. Reporting (retained action from AD 1 work-hour x $85 per 0 85 24,140
2017[dash]08-07). hour = $85. ----------------------------------------------------------------------------------------------------------------

This AD adds no additional economic burden.
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 known 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 topenalty 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

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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 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.