2013-19524. Airworthiness Directives; Learjet Inc. Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede an existing airworthiness directive (AD) that applies to certain Learjet Inc. Model 60 airplanes. The existing AD currently requires determining if a certain fuel crossflow tube is installed; and follow-on/corrective actions, as applicable. Since we issued that AD, we have received a report that airplanes produced since 2003 might also be subject to the unsafe condition; and that the minimum allowable clearance is not established in the airplane maintenance information, and therefore, must be addressed by this proposed AD. This proposed AD would retain all actions in the previous AD, and would require determining if a certain fuel crossflow tube is installed, performing repetitive measurements of the fuel crossflow tube and surrounding valves and cables, and doing corrective actions if applicable. In addition, this proposed AD expands the applicability of the existing AD. We are proposing this AD to prevent chafing and consequent failure of the fuel crossflow tube due to inadequate clearance between the tube and the flight control cables, which could result in loss of fuel from one fuel tank during normal operating conditions or loss of fuel from both main fuel tanks during fuel cross-feeding operations.

DATES:

We must receive comments on this proposed AD by September 27, 2013.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone [phone]; fax [phone]; email [e-mail]; 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, WA. 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;​; 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 (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Jeff Janusz, Aerospace Engineer, Propulsion Branch, ACE-116W, FAA, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Wichita, Kansas 67209; phone: [phone]; fax: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

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-2013-0691; Directorate Identifier 2012-NM-170-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

On September 16, 2003, we issued AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003), for certain Learjet Inc. Model 60 airplanes. That AD requires a review of airplane maintenance records or an inspection to determine if a fuel crossflow tube having a certain part number is installed; and follow-on/corrective actions, as applicable. That AD resulted from reports of chafing of the fuel crossflow tube by flight control cables. We issued that AD to prevent chafing and consequent failure of the fuel crossflow tube due to inadequate clearance between the tube and the flight control cables, which could result in loss of fuel from one fuel tank during normal operating conditions or loss of fuel from both main fuel tanks during fuel cross-feeding operations.

Actions Since Existing AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003) Was Issued

Since we issued AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003), we have received a report that airplanes produced since 2003 might be subject to the unsafe condition; and that the minimum allowable clearance is not established in the airplane maintenance information, and therefore, must be addressed by this proposed AD.

FAA's Determination

We are proposing 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.

Proposed AD Requirements

This proposed AD would retain all requirements of AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003). This proposed AD would retain all actions in the previous AD, and would require determining if a certain fuel crossflow tube is installed, performing repetitive measurements of the fuel crossflow tube and surrounding valve and cables, and doing corrective actions if applicable.

Differences Between the AD and the Service Information

Although Bombardier Alert Service Bulletin A60-28-3, Revision 2, dated October 26, 1998, applies to Learjet Inc. Model 60 airplanes, serial numbers 60-001 through 60-145 inclusive, this AD applies to Learjet Inc. Model 60 airplanes, serial numbers 60-001 through 60-409 inclusive. Airplanes having serial numbers 60-001 through 60-409 are subject to the unsafe condition. In addition, the minimum allowable clearance is not established in the airplane maintenance information, and therefore, a repetitive measurement is necessary. This difference has been coordinated with Learjet Inc.

Change to Existing AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003)

This proposed AD would retain all requirements of AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003). Since AD 2003-19-11 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003)	Corresponding requirement in this proposed AD
paragraph (a)	paragraph (g)
paragraph (b)	paragraph (h)
paragraph (c)	paragraph (i)
paragraph (d)	paragraph (j)

Costs of Compliance

We estimate that this proposed AD affects 264 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Inspection [retained actions from AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003)]	2 work-hours × $85 per hour = $170	$2	$172	$45,408

We estimate the following costs to do any necessary replacement that would be required based on the results of the proposed 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
Replacement	4 work-hours × $85 per hour = $340	$20	$360

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 proposed 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 have 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 that the proposed regulation:

(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),

(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

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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by removing airworthiness directive (AD) 2003-19-11, Amendment 39-13314 ( 68 FR 55812, September 29, 2003), and adding the following new AD:

Learjet Inc.: Docket No. FAA-2013-0691; Directorate Identifier 2012-NM-170-AD.

(a) Comments Due Date

The FAA must receive comments on this AD action by September 27, 2013.

(b) Affected ADs

This AD supersedes AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003).

(c) Applicability

This AD applies to Learjet Inc. Model 60 airplanes, certificated in any category, serial numbers 60-001 through 60-409 inclusive.

(d) Subject

Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

This AD was prompted by reports of chafing of the fuel crossflow tube by flight control cables. We are issuing this AD to prevent chafing and consequent failure of the fuel crossflow tube due to inadequate clearance between the tube and the flight control cables, which could result in loss of fuel from one fuel tank during normal operating conditions or loss of fuel from both main fuel tanks during fuel cross-feeding operations.

(f) Compliance

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

(g) Retained Part Identification

This paragraph restates the part identification required by paragraph (a) of AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003). For serial numbers 60-001 through 60-145 inclusive: Within 25 flight hours after November 3, 2003 (the effective date of AD 2003-19-11), inspect the fuel crossflow tube to determine whether part number (P/N) 6026020-005 is installed. Instead of inspecting the tube, a review of airplane maintenance records is acceptable if the P/N of the tube can be positively determined from that review.

(h) Retained Clearance Measurement and Corrective Action for Airplanes Having Serial Numbers 60-001 Through 60-145, With Revised Repair Language

This paragraph restates the clearance measurement and corrective action required by paragraph (b) of AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003), with revised repair language. For Learjet Inc. Model 60 airplanes, serial numbers 60-001 through 60-145 inclusive: If P/N 6026020-005 is found installed during the review or inspection required by paragraph (g) of this AD, before further flight, measure the clearance between the fuel crossflow tube and the flight control cables to determine if it is at least 0.35 inch, per paragraph 2.B.(8) of the Accomplishment Instructions of Bombardier Alert Service Bulletin A60-28-3, Revision 2, dated October 26, 1998.

(1) If the clearance is 0.35 inch or more, no further action is required by this paragraph.

(2) If the clearance is less than 0.35 inch, before further flight, repair 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) Retained Part Replacement, Measurement, and Repair for Airplanes Having Serial Numbers 60-001 Through 60-055, With Revised Repair Language

This paragraph restates the clearance measurement and corrective action required by paragraph (c) of AD 2003-19-11, Amendment 39-13314 (68 FR 55812, September 29, 2003), with revised repair language. For airplanes having serial numbers 60-001 through 60-055: If P/N 6026020-005 is not found installed during the review or inspection required by paragraph (g) of this AD, within 90 days after accomplishing the review or inspection, replace the existing fuel crossflow tube with a new fuel crossflow tube having P/N 6026020-005, and measure the clearance between the newly installed fuel crossflow tube and the flight control cables, per paragraph 2.A. of the Accomplishment Instructions of Bombardier Service Bulletin 60-28-4, Revision 2, dated August 22, 2001.

(1) If the clearance is 0.35 inch or more, no further action is required by this paragraph.

(2) If the clearance is less than 0.35 inch, before further flight, repair in accordance with a method approved by the Manager, Wichita 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.

(j) Retained Part Replacement, Measurement, and Repair for Airplanes Having Serial Numbers 60-056 Through 60-145, With Revised Repair Language

This paragraph restates the clearance measurement and corrective action required by paragraph (d) of AD 2003-19-11, Amendment 39-13314 (68 FR55812, September 29, 2003), with revised repair language. For airplanes having serial numbers 60-056 through 60-145: If P/N 6026020-005 is not found installed during the review or inspection required by paragraph (g) of this AD, within 90 days after accomplishing the review or inspection, replace the existing fuel crossflow tube with a new fuel crossflow tube having P/N 6026020-005, and measure the clearance between the newly installed fuel crossflow tube and the flight control cables to determine if the clearance is at least 0.35 inch, per paragraph 2.B. of the Accomplishment Instructions of Bombardier Alert Service Bulletin A60-28-3, Revision 2, dated October 26, 1998.

(1) If the clearance is 0.35 inch or more, no further action is required by this paragraph.

(2) If the clearance is less than 0.35 inch, before further flight, repair in accordance with a method approved by the Manager, Wichita 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.

Note 1 to paragraphs (h) and (j) of this AD: Bombardier Alert Service Bulletin A60-28-3, Revision 2, dated October 26, 1998, Figure 1, Detail D, incorrectly identifies the fuel crossflow tube to be installed as P/N 6026020-001. The manufacturer is aware of this error and stated it plans to correct the part number in the next revision of the service information.

(k) New Part Identification

For airplanes having serial numbers 60-001 through 60-409 inclusive: Within 25 flight hours after the effective date of this AD, inspect the fuel crossflow tube to determine whether P/N 6026020-005 is installed. In lieu of inspecting the tube, a review of airplane maintenance records is acceptable if the P/N of the tube can be positively determined from that review.

(l) New Clearance Measurement

If P/N 6026020-005 is found installed during the inspection required by paragraph (k) of this AD, before further flight, measure the clearance between the fuel crossflow tube and both elevator control cables to determine if it is 0.35 inches or more, in accordance with paragraph 2.A.(9) of the Accomplishment Instructions of Bombardier Optional Spares Service Bulletin 60-28-4, Revision 2, dated August 22, 2001.

(1) If the clearance is 0.35 inch or more, no further action is required by this paragraph.

(2) If the clearance is less than 0.35 inch, before further flight, adjust the fit of the P/N 6026020-005 tube to provide 0.35 inch or more clearance to both elevator control cables, in accordance with paragraph 2.A.(9) of the Accomplishment Instructions of Bombardier Optional Spares Service Bulletin 60-28-4, Revision 2, dated August 22, 2001. If the tube shows any indication of chafing from the control cables, before further flight, replace the fuel cross flow tube with a new fuel cross flow tube, in accordance with paragraph 2.A.(9) of the Accomplishment Instructions of Bombardier Optional Spares Service Bulletin 60-28-4, Revision 2, dated August 22, 2001.

(m) New Repetitive Measurements

For all airplanes: As of the effective date of this AD and after accomplishing the inspection required by paragraph (g) or (k) of this AD, as applicable: Before further flight after removal, replacement, or adjustment of any crossflow tube, fuel cross flow drain valve, fuel cross flow valve or related plumbing and fittings, and elevator control cable, measure the clearance between the fuel crossflow tube and the flight control cables, in accordance with paragraph 2.A.(9) of the Accomplishment Instructions of Bombardier Optional Spares Service Bulletin 60-28-4, Revision 2, dated August 22, 2001.

(1) If the clearance is 0.35 inch or more, no further action is required by this paragraph.

(2) If the clearance is less than 0.35 inch, before further flight, adjust the fit of the P/N 6026020-005 tube to provide 0.35 inch or more clearance to both elevator control cables, in accordance with paragraph 2.A.(9) of the Accomplishment Instructions of Bombardier Optional Spares Service Bulletin 60-28-4, Revision 2, dated August 22, 2001.

(n) Reporting Requirement

Submit a report of the findings of the initial measurement required by paragraph (l) of this AD to the Wichita Manufacturing Inspection District Office, 2204 S. Tyler Rd, Wichita, KS, 67209-3001, at the applicable time specified in paragraph (n)(1) or (n)(2) of this AD. The report must include the airplane registration, serial number, the total time in service, and the measured clearance found between the fuel crossflow tube and the elevator control cables after the initial inspection. Under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120 0056.

(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.

(o) Part Installation Limitation

As of the effective date of AD, only fuel crossflow tubes having P/N 6026020-005 may be installed on any airplane.

(p) 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.

(q) 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 the Related Information section 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.

(r) Related Information

(1) For more information about this AD, contact Jeff Janusz, Aerospace Engineer, Propulsion Branch, ACE-116W, FAA, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Wichita, Kansas 67209; phone: [phone]; fax: [phone]; email: [e-mail].

(2) For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone [phone]; fax [phone]; email [e-mail]; 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, WA. For information on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on August 2, 2013.

Ross Landes,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.