Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 Series Airplanes; and Model DC-9-81 (MD-81) and DC-9-82 (MD-82) Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes; and Model DC-9-81 (MD-81) and DC-9-82 (MD-82) airplanes. This proposed AD would require repetitive detailed inspections of the upper and lower caps of the rear spar of the left and right wings, and corrective action if necessary. This proposed AD also provides an optional modification that would end the repetitive inspections. This proposed AD is prompted by reports of fatigue cracks in the upper and lower caps of the wing spar. We are proposing this AD to detect and correct fatigue cracking in the upper and lower caps of the rear spar of the left and right wings, which could result in structural failure of the wings.

DATES:

We must receive comments on this proposed AD by September 20, 2004.

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.

By 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.

For the service information identified in this proposed AD, contact Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024).

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Wahib Mina, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5324; fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-18774; Directorate Identifier 2003-NM-212-AD” in the subject line 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 submitted 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 website, 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 .

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/language and http://www.plainlanguage.gov .

Examining the Docket

You can examine the AD docket 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 DMS receives them.

Discussion

We have received a report of cracks found in the lower cap of the rear spars of the left and right wing near station Xrs=267.000 during fatigue testing of fuselage number 3 on a McDonnell Douglas DC-9-14 airplane. Fuselage number 3 had accumulated 42,900 total flight hours and 66,504 total flight cycles before being removed from service for fatigue testing. An operator of McDonnell Douglas DC-9-30 series airplanes also reported cracks found in the upper cap of the rear spar. In addition, several operators of McDonnell Douglas Model DC-9-81 (MD-81) and DC-9-82 (MD-82) airplanes reported cracks found in the upper and lower cap of the rear spar. Also, according to the manufacturer's analysis, for McDonnell Douglas Model DC-9-81 (MD-81) and DC-9-82 (MD-82) airplanes, fatigue cracking in the upper and lower caps of the rear spar of the wings at station Xrs=267.000 may initiate at about 15,000 total landing cycles as a result of loads introduced by the flap hinge fitting. Fatigue cracking in the upper and lower caps of the rear spar of the left and right wings, if not detected and corrected, could result in structural failure of the wings.

The subject area on certain Model DC-9-20, -40, and -50 series airplanes is almost identical to that on the affected Model DC-9-10 and -30 series airplanes and Model DC-9-81 (MD-81) and DC-9-82 (MD-82) airplanes. Therefore, those Model DC-9-20, -40, and -50 series airplanes may be subject to the unsafe condition revealed on the DC-9-10 and -30 series airplanes and Model DC-9-81 (MD-81) and DC-9-82 (MD-82) airplanes.

Relevant Service Information

We have reviewed McDonnell Douglas DC-9 Service Bulletin 57-179, Revision 1, dated December 21, 1994. The service bulletin describes procedures for initial and repetitive detailed inspections of the upper and lower caps of the rear spar of the left and right wings at station Xrs=267.000 for cracks, and corrective action if necessary. The corrective action includes doing the permanent repair modification or the temporary repair modification of the upper and lower caps of the rear spar. The permanent repair modification extends the compliance time for the next repetitive detailed inspection. The temporary repair modification includes doing repetitive detailed, eddy current, and ultrasonic inspections for any crack progression or any new crack, and doing the permanent repair modification if any crack progression or any new crack is found.

The service bulletin also specifies that doing the crack preventative modification described in other service bulletins eliminates the need for the repetitive inspections.

McDonnell Douglas DC-9 Service Bulletin 57-160, dated December 7, 1987; MD-80 Service Bulletin 57-177, Revision 1, dated June 12, 1989; and MD-80 Service Bulletin 57-178, Revision 1, dated June 12, 1990; describe procedures for the crack preventative modification at station Xrs=267.000. The procedures include replacing/modifying the flap hinge fitting, brace fitting, and rear spar area, as applicable.

We have determined that doing the actions specified in McDonnell Douglas DC-9 Service Bulletin 57-179, Revision 1, dated December 21, 1994, will adequately address the unsafe condition.

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. Therefore, we are proposing this AD, which would require repetitive detailed inspections of the upper and lower caps of the rear spar of the left and right wings, and corrective action if necessary. The proposed AD would require you to use McDonnell Douglas DC-9 Service Bulletin 57-179, Revision 1, dated December 21, 1994, described previously to do these actions, except as discussed under “Differences Between the Proposed AD and the Service Bulletin.”

Differences Between the Proposed AD and the Service Bulletins

Operators should note that McDonnell Douglas DC-9 Service Bulletin 57-179, Revision 1, dated December 21, 1994, specifies that, if any crack progression or any new crack is found after the temporary repair, the permanent repair modification must be done within 3,000 landings. However, this proposed AD would require that if any crack progression or new crack is detected, repair must be done before further flight per a method approved by the FAA. This difference has been coordinated with the manufacturer.

In addition, McDonnell Douglas DC-9 Service Bulletin 57-160, dated December 7, 1987; MD-80 Service Bulletin 57-177, Revision 1, dated June 12, 1989; and MD-80 Service Bulletin 57-178, Revision 1, dated June 12, 1990; specify that operators may contact the manufacturer for specific modification information. However, this proposed AD would require operators to repair those conditions per a method approved by the FAA.

Costs of Compliance

This proposed AD would affect about 583 airplanes of U.S. registry and 1,163 airplanes worldwide. The proposed inspection 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 $151,580 or $260 per airplane, per inspection cycle.

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. 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.