Airworthiness Directives; Boeing Model 777-200, -200LR, -300, and -300ER Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 777-200, -200LR, -300, and -300ER series airplanes. This proposed AD would require doing initial and repetitive inspections for cracking of the elevator actuator fittings, and replacing any cracked fitting with a new fitting. This proposed AD results from a report that a cracked left elevator actuator fitting was found on a Model 777 airplane. We are proposing this AD to detect and correct a cracked actuator fitting, which could detach from the elevator and lead to an unrestrained elevator and an unacceptable flutter condition, which could result in loss of airplane control.

DATES:

We must receive comments on this proposed AD by September 17, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• 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.
• Fax: (202) 493-2251.
• Hand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Gary Oltman, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6443; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2007-28854; Directorate Identifier 2007-NM-109-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone (800) 647-5527) is located on the ground floor of the West Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We have received a report indicating that a cracked left elevator actuator fitting was found on a Model 777 airplane with 17,346 total flight hours and 14,043 total flight cycles. The crack extended through the lower inboard flange of the fitting and into the vertical flange. Analysis by Boeing indicates that this crack resulted from fatigue due to higher than anticipated stress levels in the fitting flanges. Cracked elevator actuator fittings could lack adequate residual strength to react to design flight loads and become detached from the elevator. This condition, if not corrected, could allow a cracked actuator fitting to detach from the elevator and lead to an unrestrained elevator and an unacceptable flutter condition, which could result in loss of airplane control.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 777-55A0015, dated April 19, 2007. The service bulletin describes procedures for doing an initial dye penetrant or high-frequency eddy current (HFEC) inspection to detect cracking of the elevator actuator fittings; repetitive dye penetrant, HFEC, or detailed inspections of the fittings thereafter; and replacing any cracked fitting with a new fitting having the same part number or an approved optional part number. Compliance times for the initial inspections, depending upon airplane condition, are:

• For airplanes having 14,000 total flight-cycles or more as of the date on the service bulletin, within 90 days after the date on the service bulletin;
• For airplanes having 10,000 total flight-cycles or more, but less than 14,000 total flight-cycles, as of the date on the service bulletin, within 12 months after the date on the service bulletin or within 90 days after the airplane reaches 14,000 total flight-cycles, whichever occurs first; or
• For airplanes having less than 10,000 total flight-cycles as of the date on the service bulletin, before the accumulation of 10,000 total flight cycles or within 12 months after the date on the service bulletin, whichever occurs first.

The next inspection, depending upon the type of initial inspection, is to be done at 1,000 or 1,200 flight cycles after the initial inspection, and repetitive inspections thereafter are to be done at intervals not to exceed 350 to 1,200 flight cycles. Any fitting found cracked during any inspection must be replaced before further flight. Any replacement fitting must receive an initial inspection before the accumulation of 10,000 total flight cycles after the replacement date, and repetitive inspections thereafter as described in this paragraph.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

Interim Action

We consider this proposed AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we might consider additional rulemaking.

Costs of Compliance

There are about 619 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 138 airplanes of U.S. registry. The proposed inspections would take about 4 work hours per airplane, per inspection cycle, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $44,160, or $320 per airplane, per inspection cycle.

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 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); 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• 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.