Airworthiness Directives; Boeing Model 767 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 767 series airplanes. This proposed AD would require inspections for scribe lines in the fuselage skin at skin lap joints, the skin at certain external approved repairs, the skin around external features such as antennas, and the skin at decals; and related investigative and corrective actions if necessary. This proposed AD results from reports of scribe lines found at skin lap joints and butt joints, around external repairs and antennas, and at locations where external decals had been cut. We are proposing this AD to detect and correct scribe lines, which can develop into fatigue cracks in the skin and cause sudden decompression of the airplane.

DATES:

We must receive comments on this proposed AD by August 31, 2009.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov . Follow the instructions for submitting comments.
• Fax: 202-493-2251.
• 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: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com . You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221 or 425-227-1152.

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 (telephone 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Berhane Alazar, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6577; fax (425) 917-6590.

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-2009-0642; Directorate Identifier 2009-NM-001-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

We have received reports indicating that scribe lines have been found by 11 operators on 13 Boeing Model 767 airplanes. Scribe lines were found at skin lap joints, butt joints, around external repairs and antennas, and at locations where external decals had been cut. Many of the scribe lines appear to have been made when sealant was removed as part of preparing the airplane for repainting. The Model 767 airplanes had accumulated between 6,300 and 24,600 total flight cycles. Although no cracks resulting from scribe lines on Model 767 airplanes have been reported to Boeing, fatigue cracks can develop in the skin at scribe line locations. Fatigue cracks, if not corrected, could grow large and cause sudden decompression of the airplane.

Related ADs

This proposed AD is similar to two existing ADs. AD 2006-07-12, amendment 39-14539 (71 FR 16211, March 31, 2006), applies to Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 2007-19-07, amendment 39-15198 (72 FR 60244, October 24, 2007), applies to all Boeing Model 757-200, -200PF, and -200CB series airplanes. Those ADs require inspections to detect scribe lines in the fuselage skin at certain lap joints, butt joints, external repair doublers, and other areas; and related investigative/corrective actions if necessary. Those actions resulted from reports of fuselage skin cracks adjacent to the skin lap joints on airplanes that had scribe lines.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 767-53A0193, Revision 1, dated April 9, 2009. The service bulletin describes procedures for exploratory detailed inspections to detect scribe lines along skin lap joints, external features, external approved repairs, and decals. The service bulletin specifies removing paint and sealant from affected areas before the initial exploratory inspection. The compliance times for the exploratory inspections are 25,000, 37,500, and 50,000 total flight cycles (depending on the inspection location) plus the first scribe line inspection opportunity; or within 4,000 flight cycles after the date of the service bulletin; whichever occurs later.

The service bulletin specifies related investigative actions that include performing high frequency eddy current or ultrasonic inspections of the scribe lines to detect cracks, and the service bulletin specifies corrective actions as either repairing scribe lines and cracks or contacting Boeing for repair instructions and making the repair. The service bulletin specifies to repair cracks before further flight.

The service bulletin specifies repairing scribe lines before further flight, except when a limited return to service (LRTS) program for qualifying scribe lines would allow return to service for a limited period before scribe lines are repaired. The LRTS program includes repetitive inspections to detect cracks where scribe lines are found. To qualify for an LRTS program, scribe lines must meet certain criteria based on their depth and location. The service bulletin specifies contacting Boeing for final repair instructions, which would eliminate the need for the repetitive inspections of the LRTS program. The repetitive interval for the LRTS program is 1,500 to 9,000 flight cycles, depending on the depth and location of the scribe lines and the configuration of the airplane.

The service bulletin notes that certain inspections would not be required under the following conditions:

• The airplane had never been stripped or repainted.
• The airplane had never been stripped or repainted under the wing-to-body fairings.
• No sealant had been removed except in accordance with the specified sealant removal processes as given in Appendix A of the service bulletin.

The service bulletin specifies submitting the exploratory inspection results to Boeing.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and Service Bulletin.” This proposed AD would also require sending the results of the exploratory inspections to Boeing.

Differences Between the Proposed AD and Service Bulletin

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:

• Using a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings.

Costs of Compliance

We estimate that this proposed AD would affect 367 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

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

We 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 this 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), and

3. 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

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.