E6-7740. Airworthiness Directives; Boeing Model 767 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 Boeing Model 767 airplanes. This proposed AD would require repetitive detailed and high frequency eddy current (HFEC) inspections of the station (STA) 1809.5 bulkhead for cracking and corrective actions if necessary. This proposed AD results from fatigue cracks found in the forward outer chord and horizontal inner chord at STA 1809.5. We are proposing this AD to detect and correct cracking in the bulkhead structure at STA 1809.5, which could result in failure of the bulkhead structure for carrying the flight loads of the horizontal stabilizer, and consequent loss of controllability of the airplane.

DATES:

We must receive comments on this proposed AD by July 6, 2006.

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.
• Fax: [phone].
• 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.

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

FOR FURTHER INFORMATION CONTACT:

Candice Gerretsen, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 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-2006-24814; Directorate Identifier 2006-NM-093-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 Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) 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 Docket Management System receives them.

Discussion

We have received a report indicating that two operators found fatigue cracks in the forward outer chord of the station (STA) 1809.5 airframe bulkhead, on four Boeing Model 767 airplanes. Those airplanes had accumulated between 13,942 and 29,588 total flight cycles. Also, three operators reported finding cracks in the horizontal inner chord between stringer 12L and 12R, on several Boeing Model 767 airplanes. Those airplanes had accumulated between 8,448 and 35,991 total flight cycles. Cracking in the bulkhead structure at STA 1809.5 could grow and lead to failure of the bulkhead structure for carrying the flight loads of the horizontal stabilizer. This condition, if not corrected, could result in loss of controllability of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 767-53A0131, dated March 30, 2006. The service bulletin describes procedures for accomplishing repetitive detailed and high frequency eddy current (HFEC) inspections of the STA 1809.5 bulkhead for cracking and corrective actions as applicable. Specifically, those inspections include the following:

• Part 1 of the service bulletin specifies doing a detailed inspection of the exterior of the skin at STA 1809.5 between stringers 3L and 10L and detailed and HFEC inspections of the forward outer chord and surrounding structure between stringers 3L and 10L.
• Part 2 of the service bulletin specifies doing a detailed inspection of the exterior of the skin at STA 1809.5 between stringers 3R and 10R and detailed and HFEC inspections of the forward outer chord and surrounding structure between stringers 3R and 10R.
• Part 3 of the service bulletin specifies doing detailed and HFEC inspections of the end of the horizontal inner chord and surrounding structure on the left side of the STA 1809.5 bulkhead.
• Part 4 of the service bulletin specifies doing detailed and HFEC inspections of the end of the horizontal inner chord and surrounding structure on the right side of the STA 1809.5 bulkhead.

The corrective actions include the following:

• Repairing any cracking found in the forward outer chord or in the horizontal inner chord. Repairing all cracking in a certain area terminates the repetitive inspections for that area only.
• Contacting the manufacturer for repair instructions if any cracking is found in the skin or in any structure other than the forward outer chord or horizontal inner chord.

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, except as discussed under “Difference Between the Proposed AD and Service Bulletin.”

Difference Between the Proposed AD and Service Bulletin

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:

• Using a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings.

Costs of Compliance

There are about 903 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 405 airplanes of U.S. registry. The proposed actions would take about 12 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 $388,800, or $960 per airplane, 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):

Boeing: Docket No. FAA-2006-24814; Directorate Identifier 2006-NM-093-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by July 6, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Model 767-200, -300, -300F, and -400ER series airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from cracks found in the forward outer chord and horizontal inner chord at station (STA) 1809.5. We are issuing this AD to detect and correct cracking in the bulkhead structure at STA 1809.5, which could result in failure of the bulkhead structure for carrying the flight loads of the horizontal stabilizer, and consequent loss of controllability 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.

Repetitive Inspections and Corrective Actions

(f) Before the accumulation of 15,000 total flight cycles, or within 3,000 flight cycles after the effective date of this AD, whichever is later: Do the detailed and high frequency eddy current (HFEC) inspections for cracking as specified in Parts 1, 2, 3, and 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0131, dated March 30, 2006; and do all corrective actions before further flight; by accomplishing all the actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 767-53A0131, dated March 30, 2006, except as provided by paragraph (g) of this AD. Repeat the inspections thereafter at intervals not to exceed 6,000 flight cycles. Accomplishing the corrective action for the inspections specified in Part 1, 2, 3, or 4 of the service bulletin, as applicable, terminates the repetitive inspections for that area only.

Exception to Service Bulletin

(g) If any cracking is found in the skin or in any structure other than the forward outer chord or horizontal inner chord, during any inspection required by this AD, and Boeing Alert Service Bulletin 767-53A0131, dated March 30, 2006, specifies to contact Boeing for appropriate action: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (h) of this AD.

Alternative Methods of Compliance (AMOCs)

(h)(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) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

(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 May 15, 2006.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.