Airworthiness Directives; The Boeing Company Model 767-300 Series 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 Model 767-300 series airplanes. This proposed AD would require repetitive inspections for cracks in the fuselage skin and backup structure at the lower very high frequency (VHF) antenna cutout at station 1197 + 99 between stringers 39L and 39R, and corrective actions if necessary. Certain repairs would terminate certain inspection requirements. This proposed AD results from reports of cracking found in the section 46 fuselage lower skin around the periphery of the VHF antenna baseplate at station 1197 + 99. We are proposing this AD to detect and correct fatigue cracks in the fuselage skin and internal backup structure, which could result in rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by September 27, 2010.

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.

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-2010-0796; Directorate Identifier 2010-NM-007-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 been advised that two operators reported cracks found in the section 46 fuselage lower skin around the periphery of the VHF antenna baseplate at station 1197 + 99. One operator reported 5 cracks, with a maximum length of 11 inches, found on an airplane that had accumulated 38,804 total flight hours and 34,929 total flight cycles. Another operator reported a maximum crack length of 9.5 inches found on an airplane that had accumulated 60,467 total flight hours and 29,185 total flight cycles. Boeing investigation has revealed that the fuselage skin and internal backup structural cracks are attributed to fatigue. This fatigue is the result of bending loads in the skin caused by vibration of the antenna in flight. No operator reported crack findings for the backup structure. Fatigue cracks in the fuselage skin and internal backup structure, if not corrected, could result in rapid decompression of the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 767-53-0207, dated December 17, 2009. The service bulletin describes procedures for repetitive inspections for cracks in the fuselage skin and backup structure at the lower VHF antenna cutout at station 1197 + 99, between stringers 39L and 39R. The inspections include an external detailed inspection of the fuselage skin at the lower aft VHF antenna cutout, and an internal detailed inspection of the backup structure.

Corrective actions include repairing fuselage skin cracks, which would eliminate the need to repeat the external detailed inspection; and repairing or replacing cracked backup structure parts.

In the service bulletin, the compliance time for the external detailed inspection is before the accumulation of 25,000 total flight cycles, or within 3,000 flight cycles after the date on the service bulletin, whichever occurs later. The compliance time for the internal detailed inspection is before the accumulation of 25,000 total flight cycles, or within 3,000 flight cycles after the date on the service bulletin, whichever occurs later; or the inspection may be deferred for an additional 6,000 flight cycles if no fuselage skin cracks are found during the external detailed inspection.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined that 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.

Costs of Compliance

We estimate that this proposed AD would affect 93 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.