E7-24383. Airworthiness Directives; Boeing Model 757-200, -200PF, and -200CB 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 Model 757-200, -200PF, and -200CB series airplanes. This proposed AD would require doing an ultrasound inspection for disbonded tear straps not mechanically fastened to the skin, and related investigative and corrective actions, if necessary. This proposed AD results from reports indicating that bonded skin panels may not have been correctly anodized in phosphoric acid before the tear strap doubler was bonded to the skin. We are proposing this AD to detect and correct a weak bond between the skin and tear strap. Such disbonding could reduce the ability of the skin to resist cracks and could adversely affect the structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by January 31, 2008.

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 AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

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:

Jason Deutschman, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; 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-2007-0270; Directorate Identifier 2007-NM-211-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 indicating that bonded skin panels may not have been correctly anodized in phosphoric acid before the tear strap doubler was bonded to the skin between stations 439 to 900, and 1180 to 1621, and between stringers 10 left and 10 right, on Boeing Model 757-200, -200PF, and -200CB series airplanes. The cause of the disbonded tear straps has been attributed to a manufacturing process error. A weak bond between the skin and tear strap, if not corrected, could reduce the ability of the skin to resist cracks and could adversely affect the structural integrity of the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 757-53-0077, Revision 1, dated August 6, 2007. The service bulletin describes procedures for doing an ultrasound inspection for disbonded tear straps not mechanically fastened to the skin between stations 439 to 900, and 1180 to 1621, and between stringers 10 left and 10 right, and doing applicable related investigative and corrective actions. The related investigative actions include doing a high frequency eddy current inspection to detect cracks around the fasteners, and doing a low frequency eddy current inspection to detect corrosion on the surface, as applicable. The corrective actions include installing rivets to repair disbonding, and contacting Boeing for crack and/or corrosion repair, as applicable.

The service bulletin also specifies the following compliance times for:

• Related investigative actions: Before further flight.
• Corrective actions: Before further flight or within 3,000 flight cycles after the disbonding is found, depending on the location of the disbond.

Accomplishing the actions specified in the service information is intended to 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. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

There are about 744 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 487 airplanes of U.S. registry. The proposed actions would take about 16 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $623,360, or $1,280 per airplane.

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):

Boeing: Docket No. FAA-2007-0270; Directorate Identifier 2007-NM-211-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 31, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 757-200, -200PF, and -200CB series airplanes, certificated in any category; as identified in Boeing Special Attention Service Bulletin 757-53-0077, Revision 1, dated August 6, 2007.

Unsafe Condition

(d) This AD results from reports indicating that bonded skin panels may not have been correctly anodized in phosphoric acid before the tear strap doubler was bonded to the skin. We are issuing this AD to detect and correct a weak bond between the skin and tear strap. Such disbonding could reduce the ability of the skin to resist cracks and could adversely affect the 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.

Initial Inspection

(f) At the applicable initial compliance time in paragraph (f)(1) or (f)(2) of this AD, do an external ultrasound inspection for disbonded tear straps not mechanically fastened to the skin between stations 439 to 900, and 1180 to 1621, and between stringers 10 left and 10 right, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-53-0077, Revision 1, dated August 6, 2007.

(1) For airplanes with less than or equal to 21,000 total flight cycles: Before the accumulation of 24,000 total flight cycles, but no earlier than 18,000 total flight cycles.

(2) For airplanes with more than 21,000 total flight cycles: Within 3,000 flight cycles after the effective date of this AD.

Repetitive Inspection

(g) If no disbonding is found during the ultrasound inspection required by paragraph (f) of this AD, repeat the inspection once before 36,000 total flight cycles, but no earlier than 30,000 total flight cycles.

Related Investigative and Corrective Actions

(h) If any disbonding is found during the ultrasound inspection required by paragraph (f) or (g) of this AD, do the applicable related investigative and corrective actions by accomplishing all the actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-53-0077, Revision 1, dated August 6, 2007, at the applicable compliance time specified in 1.E., “Compliance,” of the service bulletin; except as provided by paragraph (i) of this AD.

(i) If any crack and/or corrosion is found during any inspection required by this AD, and Boeing Special Attention Service Bulletin 757-53-0077, Revision 1, dated August 6, 2007, specifies to contact Boeing for appropriate action: Before further flight, repair the crack and/or corrosion using a method approved in accordance with the procedures specified in paragraph (j) of this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle 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, Seattle 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.

Issued in Renton, Washington, on December 7, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.