E7-19204. Airworthiness Directives; McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 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 McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes. This proposed AD would require repetitive inspections for cracking of the overwing frames from stations 845 to 905 (MD-87 stations 731 to 791), left and right sides, and corrective actions if necessary. This proposed AD results from reports of cracked overwing frames. We are proposing this AD to detect and correct such cracking, which could sever the frame, increase the loading of adjacent frames, and result in damage to adjacent structure and loss of overall structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by November 13, 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: [phone].
• 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, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024), for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Roger Durbin, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

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-2007-29335; Directorate Identifier 2007-NM-045-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 [phone]) 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 four MD-80 operators reported six instances of cracked overwing frames. The reports indicate two failures at frame station 886 on the left side, three failures at frame station 886 on the right side, and one failure at frame station 905 on the right side. The cracking occurred on airplanes that had accumulated between 25,965 and 40,612 total flight cycles. The cracks, which originate in the upper radius of the frame inboard tab just below the floor, were caused by fatigue. Frames at stations 845 and 864, although not reported to be cracked, are also susceptible to this type of failure. All of the noted frames are a part of MD-80 principal structural element (PSE) 53.80.005 (although the inspections that would be required by this proposed AD are not included in supplemental inspections already required for PSE 53.80.005). If not corrected, an undetected crack might sever the frame, which could increase the loading of adjacent frames, result in damage to adjacent structure, necessitate extensive repair, and ultimately lead to the loss of overall structural integrity of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin MD80-53A301, Revision 1, dated May 25, 2007. The service bulletin describes procedures for inspections, using general visual and high frequency eddy current methods, to detect cracking of the overwing frames from stations 845 to 905 (MD-87 stations 731 to 791), left and right sides. The service bulletin specifies repeating the inspections within 9,300 flight cycles after any repair, within 20,000 flight cycles after any replacement, and at intervals not to exceed 9,300 flight cycles if no cracks are found. Corrective actions are done before further flight and include a blend out repair of cracks less than 0.125 inch deep, and replacement of any overwing frame with a crack 0.125 inch or deeper.

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 proposed AD. Once this modification is developed, approved, and available, we may consider additional rulemaking.

Costs of Compliance

There are about 1,189 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
4	$80	None	$320, per inspection cycle	670	$214,400, 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.

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

McDonnell Douglas: Docket No. FAA-2007-29335; Directorate Identifier 2007-NM-045-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by November 13, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from reports of cracked overwing frames. We are issuing this AD to detect and correct such cracking, which could sever the frame, increase the loading of adjacent frames, and result in damage to adjacent structure and loss of overall structural integrity of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Inspections

(f) Before the accumulation of 20,000 total flight cycles, or within 24 months after the effective date of this AD, whichever occurs later: Do general visual and high frequency eddy current inspections, and all applicable corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD80-53A301, Revision 1, dated May 25, 2007. Do the applicable corrective actions before further flight after accomplishing the inspections. Repeat the inspections thereafter at applicable intervals not to exceed those specified in paragraph 1.E., “Compliance,” of the service bulletin.

Actions According to Previous Issue of Service Bulletin

(g) Inspections and related investigative and corrective actions are also acceptable for compliance with the requirements of paragraph (f) of this AD if done before the effective date of this AD in accordance with Boeing Alert Service Bulletin MD80-53A301, dated January 9, 2007.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Los Angeles ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane and 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD.

Issued in Renton, Washington, on September 21, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.