Airworthiness Directives; Boeing Model 767-400ER Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 767-400ER series airplanes, that requires 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:

Effective May 11, 2004.

The incorporation by reference of a certain publication listed in the regulations is approved by the Director of the Federal Register as of May 11, 2004.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

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 (425) 917-6428; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Boeing Model 767-400ER series airplanes was published in the Federal Register on October 1, 2003 (68 FR 56598). That action proposed to 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.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Request To Change Compliance Time

One commenter requests that the proposed repairs be deferred until the next major base visit. The commenter states that the compliance time of “before the accumulation of 12,000 total flight cycles” in the proposed AD would cause maintenance program issues. The commenter states that the inspections and repairs will create an undue burden to the airline operators due to parts availability and the costs affiliated with immediate repair of a cracked deflection control track.

The FAA does not agree with the commenter's request to change the compliance time. In developing an appropriate compliance time for this action, we considered the safety implications, parts availability, and normal maintenance schedules for the timely accomplishment of the inspections and repairs. We have determined, based on fatigue analysis by the manufacturer, that a compliance time of “before the accumulation of 12,000 total flight cycles” will ensure an acceptable level of safety. We also provided a grace period of 1,200 flight cycles, in order to allow the operators to align the inspections with regular maintenance checks. Last, due to safety implications and the consequences associated with continued service without proper repair, repairs must be made before further flight.

Model 767-400ER Not Subject to Proposed AD

The commenter states that all of the cracked deflection control tracks were reported on Model 767-300 series airplanes and no reports have been made for Model 767-400ER series airplanes. The commenter also states that the utilization for the Model 767-300 series airplanes and Model 767-400ER series airplanes are often completely different.

We infer from the commenter's statement, that the Model 767-400ER deflection control tracks should not be subject to the proposed AD. While we do agree that the airplanes operate differently and cracking has only been found on Model 767-300 series airplanes, we do not agree with the commenter that Model 767-400ER deflection control tracks should not be subject to this AD. Based on fatigue analysis and similar construction, we find sufficient data exists to establish the probability of the deflection control track cracking on the Model 767-400ER series airplanes. Since the deflection control track acts as a secondary load path on Model 767-400ER series airplanes and not on Model 767-300 series airplanes, this AD is limited to Model 767-400ER series airplanes only.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

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 will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the 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 requirements of this AD action, and that no operator would accomplish those actions in the future if this 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 adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

2. Section 39.13 is amended by adding the following new airworthiness directive:

2004-07-11 Boeing: Amendment 39-13555. 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.

Incorporation by Reference

(e) The actions shall be done in accordance with Boeing Alert Service Bulletin 767-27A0183, dated May 9, 2002. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

(f) This amendment becomes effective on May 11, 2004.