Airworthiness Directives; The Boeing Company Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F 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 all Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series airplanes. This proposed AD would require repetitive detailed inspections of the aft pressure bulkhead web for cracking, and repair if necessary. For certain airplanes, this proposed AD also would provide for an optional preventative modification of the aft pressure bulkhead web, which would terminate certain repetitive detailed inspections. This proposed AD results from reports of cracks in the aft pressure bulkhead web. We are proposing this AD to detect and correct cracking in the aft pressure bulkhead web, which could adversely affect the structural integrity of the airplane, resulting in difficulty maintaining cabin pressurization or rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by August 16, 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, 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-2010-0646; Directorate Identifier 2009-NM-223-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 13 reports of cracks in the aft pressure bulkhead web ranging from 0.75 inch to 11.8 inches in length at the buttock line 61, between water line (WL) 220 and WL 228. The cracks originated at the hydraulic line support brackets, which were installed in production after airplane line number 1136, or in accordance with Boeing Service Bulletin 727-29-0057. The cracks were found in airplanes that had accumulated between 14,939 total flight hours and 39,369 total flight hours, and between 10,685 total flight cycles and 29,357 total flight cycles. The cracking is attributed to fatigue of the aft pressure bulkhead web due to vibrations from the number 1 engine hydraulic pump line, in addition to normal pressurization cycles. Material analysis revealed multiple crack initiation sites and no evidence of corrosion. This condition, if not corrected, could result in difficulty maintaining cabin pressurization or rapid decompression of the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 727-53-0232, dated September 23, 2009. This service bulletin describes procedures for initial and repetitive detailed inspections of the aft pressure bulkhead web for any cracking around the hydraulic line support bracket, and repair of any crack found. For certain airplanes, this service bulletin describes procedures for installing an optional preventative modification if no cracking is found during the detailed inspections. The preventative modification includes doing high frequency eddy current (HFEC) inspections of the open fastener holes and installing a modification doubler on the aft side of the bulkhead web, which would eliminate the need for certain repetitive inspections. If any cracking is found during the detailed or HFEC inspection, this service bulletin specifies contacting Boeing for repair instructions and installing the repair.

The compliance times for the initial inspection range between 3,500 flight cycles from the date on the service bulletin and 7,000 flight cycles since the previous inspection. The compliance time for repairing any cracking is before further flight. The interval for repeating the detailed inspection ranges between 1,000 flight cycles and 12,000 flight cycles, depending on airplane configuration, the time since the last inspection, and the type of the last inspection.

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 the Service Information.”

Differences Between the Proposed AD and the Service Information

Boeing Special Attention Service Bulletin 727-53-0232, dated September 23, 2009, 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:

• In accordance with a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) whom we have authorized to make those findings.

Boeing Special Attention Service Bulletin 727-53-0232, dated September 23, 2009, provides damage tolerance inspections in Table 3 of paragraph 1.E. of that service bulletin. Note 1 of this proposed AD relates to these damage tolerance inspections, which are not required for compliance with this proposed AD.

Costs of Compliance

We estimate that this proposed AD would affect 243 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.