2010-19292. Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F Airplanes; and Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Model DC-9-14 and DC-9-15 airplanes; and Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes. The existing AD currently requires repetitive high frequency eddy current inspections to detect cracking in the vertical radius (also known as the “vertical leg”) of the upper cap of the center wing rear spar, and repair if necessary. This proposed AD expands the area to be inspected by including inspections to detect cracking of the horizontal flange of the upper cap of the left and right center wing rear spar, and repair if necessary. This proposed AD also adds certain airplanes to the applicability. This proposed AD results from reports of cracking in the vertical radius of the upper cap of the center wing rear spar, and the horizontal flange on the inboard side of the rear spar upper cap, which resulted from stress corrosion. We are proposing this AD to detect and correct cracking in the vertical leg or the horizontal flange of the upper cap of the left or right center wing rear spar, which could cause a possible fuel leak, damage to the wing skin, and structural failure of the upper cap, and result in reduced structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by September 20, 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: [phone].
• 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, 3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-0001; telephone [phone], extension 2; fax [phone]; e-mail [e-mail]; 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 [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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 [phone]; fax [phone].

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-2010-0705; Directorate Identifier 2009-NM-206-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

On November 1, 2004, we issued AD 2004-23-11, Amendment 39-13866 (69 FR 65522, November 15, 2004), for certain Model DC-9-14 and DC-9-15 airplanes; and Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes. That AD requires repetitive high frequency eddy current inspections to detect cracks in the vertical radius (also known as the “vertical leg”) of the upper cap of the center wing rear spar, and repair if necessary. That AD resulted from reports of cracks in the upper cap of the center wing rear spar that resulted from stress corrosion. We issued that AD to detect and correct cracking of the left or right upper cap of the center wing rear spar, which could cause a possible fuel leak and structural failure of the upper cap, and result in reduced structural integrity of the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2004-23-11, one operator reported finding two cracks in the horizontal flange on the inboard side of the rear spar upper cap, and Boeing's investigation determined that the cracks resulted from stress corrosion.

Relevant Service Information

We have reviewed Boeing Service Bulletin DC9-57-223, Revision 1, dated August 13, 2009, which adds Model DC-9-15F airplanes to the applicability. The service bulletin describes procedures for doing repetitive high frequency eddy current inspections of the vertical leg and horizontal flange of the upper caps of the left and right center wing rear spar, inboard and outboard sides, of the bulkhead at wing station Xcw = 58.500 for cracking. The service bulletin specifies to contact Boeing for repair instructions if any cracking is found during the inspections. We referred to the original issue of the service bulletin for accomplishing the inspections required by AD 2004-23-11.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to develop on other airplanes of the same type design. For this reason, we are proposing this AD, which would supersede AD 2004-23-11 and would continue to require repetitive high frequency eddy current inspections to detect cracks in the vertical radius (also known as the “vertical leg”) of the upper cap of the center wing rear spar, and repair if necessary. This proposed AD would also require repetitive inspections for cracking in the horizontal flange of the upper cap of the left or right center wing rear spar, and repair if necessary.

Differences Between the Proposed AD and Service Information

Where Boeing Service Bulletin DC9-57-223, Revision 1, dated August 13, 2009, specifies to contact Boeing for repair instructions, this proposed AD requires operators to repair any cracking in accordance with a method approved in accordance with paragraph (k) of the AD.

Change to Existing AD

This proposed AD would retain certain requirements of AD 2004-23-11. Since AD 2004-23-11 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2004-23-11	Corresponding requirement in this proposed AD
Paragraph (f)	paragraph (g).
Paragraph (g)	paragraph (h).

Costs of Compliance

There are approximately 510 airplanes of the affected design in the worldwide fleet. We estimate that 322 airplanes of U.S. registry would be affected by this proposed AD. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.- registered airplanes	Fleet cost
Inspection	3	$85	$0	$255 per inspection cycle	322	$82,110 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
• 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by removing Amendment 39-13866 (69 FR 65522, November 15, 2004) and adding the following new AD:

McDonnell Douglas Corporation: Docket No. FAA-2010-0705; Directorate Identifier 2009-NM-206-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by September 20, 2010.

Affected ADs

(b) This AD supersedes AD 2004-23-11, Amendment 39-13866.

Applicability

(c) This AD applies to McDonnell Douglas Corporation Model DC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-33F, DC-9-34, DC-9-34F, DC-9-32F (C-9A, C-9B), DC-9-41, and DC-9-51 airplanes; certificated in any category; as identified in Boeing Service Bulletin DC9-57-223, Revision 1, dated August 13, 2009.

Subject

(d) Air Transport Association (ATA) of America Code 57: Wings.

Unsafe Condition

(e) This AD results from reports of cracking in the vertical radius (also known as the “vertical leg”) of the upper cap of the center wing rear spar, and the horizontal flange on the inboard side of the rear spar upper cap, which resulted from stress corrosion. The Federal Aviation Administration is issuing this AD to detect and correct cracking in the vertical leg or the horizontal flange of the upper cap of the left or right center wing rear spar, which could cause a possible fuel leak, damage to the wing skin, and structural failure of the upper cap, and result in reduced structural integrity of the airplane.

Compliance

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

Restatement of Requirements of AD 2004-23-11, With Revised Service Information

Inspection

(g) For all airplanes except Model DC-9-15F airplanes, at the later of the times specified in paragraphs (g)(1) and (g)(2) of this AD: Do a high frequency eddy current inspection to detect cracks in the vertical radius of the upper cap of the center wing rear spar, in accordance with the Accomplishment Instructions of Boeing Service Bulletin DC9-57-223, dated July 21, 2003; or Revision 1, dated August 13, 2009. After the effective date of this AD, only Revision 1 may be used.

(1) Before the accumulation of 25,000 total flight cycles.

(2) Within 15,000 flight cycles or 5 years after December 20, 2004 (the effective date of AD 2004-23-11), whichever occurs first.

Corrective Action

(h)(1) If no crack is found during any inspection required by paragraph (g) of this AD, then repeat the inspection thereafter at intervals not to exceed 15,000 flight cycles or 5 years, whichever occurs first, until the initial inspection required by paragraph (i) of this AD is done.

(2) If any crack is found during the inspection required by paragraph (g) of this AD, before further flight, repair per a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Los Angeles ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.

New Requirements of This AD

Inspection

(i) At the later of the times specified in paragraphs (i)(1) and (i)(2) of this AD: Do a high frequency eddy current inspection to detect cracking in the vertical leg (also known as the “vertical radius”) and horizontal flange of the left and right rear spar upper cap, inboard and outboard sides, at the bulkhead at wing station Xcw = 58.500, in accordance with the Accomplishment Instructions of Boeing Service Bulletin DC9-57-223, Revision 1, dated August 13, 2009. If no cracking is found, repeat the inspection thereafter at intervals not to exceed 15,000 flight cycles or 5 years, whichever occurs first. Accomplishment of the initial inspection required by paragraph (i) of this AD terminates the requirements of paragraphs (g) and (h)(1) of this AD.

(1) Before the accumulation of 25,000 total flight cycles.

(2) Within 15,000 flight cycles or 5 years after accomplishing the most recent high frequency eddy current inspection required by paragraph (g) of this AD, whichever occurs first.

Corrective Action

(j) If any cracking is found during any inspection required by paragraph (i) of this AD, before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (k) of this AD.

Alternative Methods of Compliance (AMOCs)

(k)(1) The Manager, Los Angeles ACO, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Wahib Mina, Aerospace Engineer, Airframe Branch, ANM-120L, Los Angeles ACO, FAA, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

(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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically refer to this AD.

(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 the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that 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 the approval must specifically refer to this AD.

(4) AMOCs approved previously in accordance with AD 2004-23-11, Amendment 39-13866, are approved as AMOCs for the corresponding provisions of paragraph (h)(2) of this AD.

Issued in Renton, Washington, on July 27, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.