2010-33001. Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Model DC-10-10, DC-10-10F, and MD-10-10F airplanes. This proposed AD would require repetitive inspections for cracking on the lower cap of the rear spar of the left and right wings between stations Xors=417 and the outboard edge of the lower cap splice of the wing rear spar at station Xors=400; temporary and permanent repairs if necessary; and repetitive inspections of repaired areas and corrective actions if necessary. This proposed AD results from reports of three instances of fuel leaks in the lower cap splice of the wing rear spar at station Xors=409. We are proposing this AD to detect and correct cracking on the lower cap of the rear spar of the left and right wings between stations Xors=417 and the outboard edge of the lower cap splice of the wing rear spar at station Xors=400, which could result in fuel leaks or cracking of the lower wing skin and structure, causing possible inability of the structure to sustain the limit load adversely affecting the structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by February 14, 2011.

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:

Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; phone: [phone]; fax: [phone]; e-mail: [e-mail].

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-2010-1206; Directorate Identifier 2009-NM-216-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

We have received reports of three instances of Model DC-10-10F and MD-10-10F airplanes having a fuel leak in the lower cap of the wing rear spar at station Xors=409. Affected airplanes had the gross weight doublers installed, and operators had previously accomplished Boeing Service Bulletin DC10-57-138. Investigation revealed the fuel leak was due to a crack in the lower cap. This crack extended into all three legs (aft, forward, and vertical) of the spar cap. Metallurgical analysis of the cracked portion of the spar cap determined that the crack was due to fatigue and began at a fastener hole in the aft leg of the spar cap. An undetected crack in a spar cap, if not corrected, could lead to fuel leaks or cracking of the lower wing skin and structure causing the possible inability of the structure to sustain the limit load, and adversely affect the structural integrity of the airplane.

The design of the spar caps on Model DC-10-10 airplanes is the same as that on Model DC-10-10F and MD-10-10F airplanes in the area of cracking; therefore, Model DC-10-10 airplanes are also subject to the identified unsafe condition.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin DC10-57A156, Revision 1, dated March 10, 2010. The service bulletin describes procedures for repetitive eddy current test high frequency (ETHF) inspections for cracking on the lower cap of the rear spar of the left and right wings between stations Xors=417 and the outboard edge of the lower cap splice of the wing rear spar at station Xors=400, and temporary and permanent repairs, if necessary. The temporary repair may only be done on airplanes on which a crack that extends into the vertical leg of the spar cap is found and includes stop drilling the crack and installing an external doubler. The service bulletin describes procedures for repetitive ETHF and ultrasonic inspections for cracking of the repaired area.

We have also reviewed Boeing DC-10-10 Service Rework Drawings SR10570048, Revision J, dated July 16, 2009; which describe procedures for permanent and temporary repairs. The type of permanent repair depends on the extent of the cracking and includes crack removal or stop drill end of the crack and structural reinforcement. For permanently and temporarily repaired areas, the service rework drawing describes procedures for repetitive ETHF and ultrasonic inspections for cracking (depending on the type of repair that is accomplished).

We have also reviewed Boeing DC-10-10 Service Rework Drawings SR10570019, Revision K, dated April 17, 2009, which describe procedures for permanent repairs. The type of permanent repair depends on the extent of the cracking and includes crack removal or stop drill end of the crack and structural reinforcement. For permanently repaired areas, the service rework drawing describes procedures for repetitive ETHF and ultrasonic inspections for cracking (depending on the type of repair that is accomplished).

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously except as discussed under “Differences Between the Proposed AD and the Service Information.”

Differences Between the Proposed AD and the Service Information

Because the service bulletin provides no corrective action for the post repair inspections, this AD would require contacting the FAA.

Costs of Compliance

We estimate that this proposed AD would affect 68 airplanes of U.S. registry. We also estimate that it would take 2 work-hours per product to comply with this proposed AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this proposed AD to the U.S. operators to be $11,560, or $170 per product, 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 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 this 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

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 adding the following new AD:

McDonnell Douglas Corporation: Docket No. FAA-2010-1206; Directorate Identifier 2009-NM-216-AD.

Comments Due Date

(a) We must receive comments by February 14, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F airplanes; certificated in any category; as identified in Boeing Alert Service Bulletin DC10-57A156, Revision 1, dated March 10, 2010.

Subject

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

Unsafe Condition

(e) This AD results from reports of three instances of fuel leaks in the lower cap splice of the wing rear spar at station Xors=409. The Federal Aviation Administration is issuing this AD to detect and correct cracking on the lower cap of the rear spar of the left and right wings between stations Xors=417 and the outboard edge of the lower cap splice of the wing rear spar at station Xors=400, which could result in fuel leaks or cracking of the lower wing skin and structure, causing possible inability to sustain the limit load and adversely affecting the 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.

Inspection

(g) Within 1,750 flight cycles after the effective date of this AD, do an eddy current test high frequency (ETHF) inspection for cracking on the lower cap of the rear spar of the left and right wings between stations Xors=417 and the outboard edge of the lower cap splice of the wing rear spar at station Xors=400, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin DC10-57A156, Revision 1, dated March 10, 2010.

(1) If no cracking is found, repeat the inspection required by paragraph (g) of this AD thereafter at intervals not to exceed 1,750 flight cycles.

(2) If any cracking is found in the spar cap aft leg at the fastener holes, and that cracking can be removed by hole enlargement, before further flight, do a permanent repair, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570048, Revision J, dated July 16, 2009. Within 1,750 flight cycles after doing the applicable permanent repair, and thereafter at intervals not to exceed 1,750 flight cycles, do an ETHF inspection for cracking in accordance with Boeing DC-10-10 Service Rework Drawing SR10570048, Revision J, dated July 16, 2009. If any cracking is found during any inspection required by this paragraph, before further flight, repair the cracking, in accordance with the procedures specified in paragraph (i) of this AD.

(3) If any cracking is found in the spar cap aft leg at the fastener holes, and that cracking cannot be removed by hole enlargement but it does not extend into the vertical leg, before further flight, do a permanent repair, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570048, Revision J, dated July 16, 2009. Within 4,550 flight cycles after doing a permanent repair, and thereafter at intervals not to exceed 4,550 flight cycles, do ETHF and ultrasonic inspections for cracking, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570048, Revision J, dated July 16, 2009. If any cracking is found during any inspection required by this paragraph, before further flight, repair the cracking, in accordance with the procedures specified in paragraph (i) of this AD.

(4) If any cracking is found in the spar cap aft leg at fastener holes and that cracking extends into the vertical leg of the spar cap, do the actions specified in paragraph (g)(4)(i) or (g)(4)(ii) of this AD.

(i) Do the actions in paragraphs (g)(4)(i)(A) and (g)(4)(i)(B) of this AD.

(A) Before further flight, do a temporary repair in accordance with Boeing DC-10-10 Service Rework Drawing SR10570048, Revision J, dated July 16, 2009. Within 1,650 flight cycles after doing the temporary repair; and thereafter at intervals not to exceed 1,650 flight cycles, do ETHF and ultrasonic inspections for cracking of the repaired area, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570048, Revision J, dated July 16, 2009, until the permanent repair required by paragraph (g)(4)(i)(B) of this AD is done. If any cracking is found during any inspection required by this paragraph, before further flight, repair the cracking, in accordance with the procedures specified in paragraph (i) of this AD.

(B) Within 7,000 flight cycles after the temporary repair has been done, do the applicable permanent repair, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570019, Revision K, dated April 17, 2009. Within 4,550 flight cycles after doing the permanent repair; and thereafter at intervals not to exceed 4,550 flight cycles; do ETHF and ultrasonic inspections for cracking of the repaired area, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570019, Revision K, dated April 17, 2009. If any cracking is found during any inspection required by this paragraph, before further flight, repair the cracking, in accordance with the procedures specified in paragraph (i) of this AD.

(ii) Before further flight do the applicable permanent repair, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570019, Revision K, dated April 17, 2009. Within 4,550 flight cycles after doing the permanent repair; and thereafter at intervals not to exceed 4,550 flight cycles, do ETHF and ultrasonic inspections for cracking of the repaired area, in accordance with Boeing DC-10-10 Service Rework Drawing SR10570019, Revision K, dated April 17, 2009. If any cracking is found during any inspection required by this paragraph, before further flight, repair the cracking, in accordance with the procedures specified in paragraph (i) of this AD.

Credit for Actions Accomplished in Accordance With Previous Service Information

(h) Actions accomplished before the effective date of this AD according to Boeing Alert Service Bulletin DC10-57A156, dated September 16, 2009, are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Los Angeles Aircraft Certification Office, (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: Nenita Odesa, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 3960 Paramount Boulevard, Lakewood, California 90712-4137; phone: [phone]; fax: [phone]; e-mail: [e-mail].

(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 reference 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 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD.

Issued in Renton, Washington, on December 17, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.