Airworthiness Directives; Boeing Model 727, 727C, 727-100, 727-100C, and 727-200 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 certain Boeing transport category airplanes. This proposed AD would require determining if the terminal fittings of the spars of the wings are made of 7079 aluminum alloy material. For any positive finding, the proposed AD would require doing repetitive inspections for cracks and corrosion of all exposed surfaces of the terminal fitting bores; doing repetitive inspections for cracks, corrosion, and other surface defects, of all exposed surfaces, including the flanges, of the terminal fitting; applying corrosion inhibiting compound to the terminal fittings; and repairing or replacing any cracked, corroded, or defective part with a new part. This proposed AD also provides for an optional terminating action for the repetitive inspections. This proposed AD results from reports of cracking of the terminal fittings of the spars of the wings. We are proposing this AD to detect and correct stress-corrosion cracking of the terminal fittings, which could result in the failure of one of the terminal fitting connections. Such a failure, combined with a similar failure of one of the other three terminal fittings, could result in the inability of the airplane structure to carry fail-safe loads, which could result in loss of structural integrity of the wing attachment points.

DATES:

We must receive comments on this proposed AD by March 13, 2006.

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: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
• Fax: (202) 493-2251.
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., 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:

Daniel F. Kutz, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6456; 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-2006-23672; Directorate Identifier 2005-NM-237-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 Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif 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 reports of cracking of the terminal fittings of the front and rear spars of the wings. The affected terminal fittings were made from a 7079-T6 aluminum forging. This material is known to be susceptible to stress-corrosion cracking. This condition, if not detected and corrected, could result in the failure of one of the terminal fitting connections. Such a failure, combined with a similar failure of one of the other three terminal fittings, could result in the inability of the airplane structure to carry fail-safe loads, which could result in loss of structural integrity of the wing attachment points.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 727-57A0185, Revision 1, dated November 3, 2005. The service bulletin describes procedures for determining if the terminal fittings of the front and rear spars of the wings are made of 7079 aluminum alloy material by either inspecting the forging number or doing a conductivity test. For any case where the terminal fitting is determined to be made of 7079 aluminum alloy material or where the material cannot be determined, the service bulletin describes procedures for doing repetitive fluorescent dye penetrant inspections for cracks and corrosion of all exposed surfaces of the terminal fitting bores; doing repetitive detailed inspections for cracks, corrosion, and other surface defects, of all exposed surfaces, including the flanges, of the terminal fitting; applying corrosion inhibiting compound to the terminal fittings; and repairing any cracked, corroded, or defective part or contacting Boeing if necessary.

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, except as discussed under “Differences Between the Proposed AD and Service Bulletin.” In addition, the proposed AD would provide for an optional terminating action for the repetitive inspections. The proposed AD also would require sending the initial inspection results 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.

In paragraph 1.E., the service bulletins states, “Contact Boeing for replacement of the fitting with a fitting not made from 7079 aluminum alloy. Replacement of the fitting is considered terminating action for that fitting only.” However, the Accomplishment Instructions of the service bulletin do not contain any procedures for accomplishing this replacement. Therefore, this proposed AD specifies that the optional replacement be done in accordance with a method approved by the Manager, Seattle Aircraft Certification Office.

Interim Action

This proposed AD is considered to be interim action. The inspection reports that are required by this AD will enable the manufacturer to obtain better insight into the extent of the cracking and corrosion of the terminal fittings of the front and rear spars of the wings in the fleet, and to develop additional action if necessary to address the unsafe condition. If additional action is identified, we may consider further rulemaking.

Costs of Compliance

There are about 302 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 157 airplanes of U.S. registry. The proposed determination of forging number/material identification would take about 4 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $40,820, or $260 per airplane.

Accomplishing the fluorescent dye penetrant and detailed inspections, if required, will take about 16 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, we estimate the cost of the inspections to be $1,040 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.