03-24842. Airworthiness Directives; Boeing Model 767-400ER Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Boeing Model 767-400ER series airplanes. This proposal would require repetitive high frequency eddy current inspections of the aft lower lugs of the deflection control track of the outboard flap for cracks, and replacement of any cracked deflection control track with a new track assembly. This action is necessary to prevent fatigue cracking in the aft lower lug run-out region of the deflection control track. Fatigue cracking of the deflection control track, if not detected and corrected in a timely manner, could result in the loss of the secondary load path for the outboard flap, resulting in the loss of the outboard flap and consequent reduced controllability of the airplane in the event that the primary load path also fails. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by Novemeber 17, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-287-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-287-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

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

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2002-NM-287-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-287-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received several reports of cracked deflection control tracks on the outboard end of the outboard flaps on Boeing Model 767-300 series airplanes. These cracks all initiated in the aft lower lug run-out region. In one case, the crack initiated at inclusions that are typical of the slag products that are a result of the casting process. After a crack initiates, it is propagated by fatigue until the track fractures.

The deflection control track on Model 767-400 ER series airplanes is identical to that on the affected Model 767-300 series airplanes. However, on the Model 767-300 series airplanes the deflection control track does not act as a load path, so the Model 767-300 series airplanes are not subject to mandatory action for this condition at this time. Fatigue analysis for the Model 767-400ER series airplanes showed that the cracking should not occur before 12,000 total flight cycles. Fatigue cracking of the deflection control track for Model 767-400ER series airplanes, if not detected and corrected in a timely manner, could result in the loss of the secondary load path for the outboard flap resulting in the loss of the outboard flap and consequent reduced controllability of the airplane in the event that the primary load path also fails.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 767-27A0183, dated May 9, 2002, which describes procedures for repetitive high frequency eddy current inspections of the aft lower lugs of the deflection control track of the outboard flap for cracks, and replacement of any cracked deflection control track with a new track assembly.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Changes to 14 CFR Part 39/Effect on the Proposed AD

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance (AMOCs). Because we have now included this material in part 39, only the office authorized to approve AMOCs is identified in each individual AD.

Change to Labor Rate Estimate

We have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

Cost Impact

There are approximately 38 airplanes of the affected design in the worldwide fleet. The FAA estimates that 38 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 3 work hours per airplane to accomplish the proposed inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $7,410, or $195 per airplane, per inspection cycle.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2002-NM-287-AD.

Applicability: All Model 767-400ER series airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue cracking in the aft lower lug run-out region of the deflection control track, which could result in the loss of the secondary load path for the outboard flap, resulting in loss of the outboard flap and consequent reduced controllability of the airplane in the event that the primary load path also fails, accomplish the following:

Initial Inspection

(a) Before the accumulation of 12,000 total flight cycles, or within 1,200 flight cycles after the effective date of this AD, whichever occurs later, perform a high frequency eddy current (HFEC) inspection for cracks in the aft lower lug of the deflection control track on the outboard flap, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 767-27A0183, dated May 9, 2002.

Repetitive Inspections

(b) If no crack is detected during any HFEC inspection required in paragraph (a) of this AD, repeat the inspection at intervals not to exceed 1,200 flight cycles.

Corrective Action

(c) If any crack is detected during any HFEC inspection required by paragraph (a) of this AD, before further flight, replace the deflection control track with a new track assembly, in accordance with the Accomplishment Instructions in Boeing Alert Service Bulletin 767-27A0183, dated May 9, 2002. Within 12,000 flight cycles following the replacement, perform the HFEC inspection specified in paragraph (a) of this AD, and repeat inspections as specified in paragraph (b) of this AD.

Alternative Methods of Compliance

(d) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD.

Issued in Renton, Washington, on September 25, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.