03-30337. Airworthiness Directives; Boeing Model 767 Series Airplanes Powered by General Electric or Pratt & Whitney Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes powered by General Electric or Pratt & Whitney engines, that currently requires repetitive inspections to detect discrepancies of the four aft-most fastener holes in the horizontal tangs of the midspar fitting of the strut, and corrective actions, if necessary. That AD also provides an optional terminating action for repetitive inspections. This proposal would expand the area on which the inspections are required. This proposal is prompted by reports of cracking at the third row of fasteners in the midspar fitting. The actions specified by the proposed AD are intended to prevent fatigue cracking in the primary strut structure and reduced structural integrity of the strut, which could result in separation of the strut and engine. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 22, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-275-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-275-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:

Suzanne Masterson, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington; 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-275-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-275-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On April 2, 2001, the FAA issued AD 2001-07-05, amendment 39-12170 (66 FR 18523, April 10, 2001), applicable to certain Boeing Model 767 series airplanes powered by General Electric or Pratt & Whitney engines, to require repetitive inspections to detect discrepancies of the aft-most fastener holes in the horizontal tangs of the midspar fitting of the strut, and corrective actions, if necessary. That AD was also prompted by a report indicating fatigue cracking of an inboard midspar fitting on the number two pylon. The requirements of that AD are intended to prevent fatigue cracking in primary strut structure and reduced structural integrity of the strut, which could result in separation of the strut and engine.

Actions Since Issuance of Previous Rule

Since the issuance of AD 2001-07-05, the FAA has received reports of cracking at the third row of fasteners in the midspar fitting. AD 2001-07-05 requires inspections of only the aft-most two rows consisting of four fastener holes in the horizontal tangs of the midspar fitting. The proposed AD expands the area for the inspections from four aft-most fastener holes in the midspar fitting to eight aft-most fastener holes in the midspar fitting.

Issuance of New Service Information

The FAA has reviewed and approved Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002, which describes repetitive inspections of eight aft-most fastener holes in the midspar fitting, rather than only four aft-most fastener holes. Except as discussed below, the inspections described in this service bulletin are essentially identical to those specified in Revision 1 of the service bulletin, which was referenced in AD 2001-07-05 as the appropriate source of service information. Accomplishment of the actions specified in Revision 3 of the service bulletin is intended to adequately address the identified unsafe condition, except as described below.

Difference Between Proposed Rule and Service Bulletin

Operators should note that, unlike the procedures described in Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002, during the first detailed inspection, this proposed AD allows for inspection of only four of the aft-most fastener holes as an option to inspecting all eight aft-most fastener holes. After the first detailed inspection, repetitive inspections would include all eight aft-most fastener holes as specified in the service bulletin.

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 supersede AD 2001-07-05 to require repetitive inspections to detect discrepancies of the eight aft-most fastener holes in the horizontal tangs of the midspar fitting of the strut, and corrective actions, if necessary.

Editorial Changes to the Existing Requirements

The FAA has changed all references to a “detailed visual inspection” in paragraph (a)(1) of AD 2001-07-05 to “detailed inspection.”

The FAA has also added the words “before further flight,” to paragraphs (a)(2)(i) and (a)(2)(ii) of the proposed AD, which were inadvertently omitted from paragraphs (a)(2)(i) and (a)(2)(ii) of AD 2001-07-05. It was our intent to follow the compliance times identified in the referenced service bulletin. We have included the compliance time for clarification.

Cost Impact

There are approximately 625 airplanes of the affected design in the worldwide fleet. The FAA estimates that 263 airplanes of U.S. registry would be affected by this proposed AD.

The detailed inspection that is proposed in this AD action would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $17,095, or $65 per airplane, per inspection cycle.

The eddy current inspection that is proposed by the AD action would take approximately 3 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $51,285, or $195 per airplane, per inspection cycle.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed 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 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 removing amendment 39-12170 (66 FR 18523, April 10, 2001), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 2002-NM-275-AD. Supersedes AD 2001-07-05, amendment 39-12170.

Applicability: Model 767 series airplanes, as listed in Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue cracking in the primary strut structure and reduced structural integrity of the strut, which could result in separation of the strut and engine, accomplish the following:

Requirements of AD 2001-07-05

Repetitive Inspections

(a) Except as provided by paragraph (b) of this AD, before the accumulation of 10,000 total flight cycles, or within 600 flight cycles after May 15, 2001 (the effective date of AD 2001-07-05, amendment 39-12170 (66 FR 18523, April 10, 2001), whichever occurs later: Accomplish the inspections required by paragraph (a)(1) or (a)(2) of this AD, as applicable.

(1) Perform a detailed inspection of the four aft-most fastener holes in the horizontal tangs of the midspar fitting of the strut to detect cracking, in accordance with Part 1, “Detailed Inspection,” of the Accomplishment Instructions of Boeing Service Bulletin 767-54A0101, Revision 1, dated February 3, 2000. If no cracking is detected, repeat the inspection thereafter at the applicable intervals specified in Table 1, “Reinspection Intervals for Part 1—Detailed Inspection” included in Figure 1 of the service bulletin.

Note 1:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

(2) Perform a high frequency eddy current inspection of the four aft-most fastener holes in the horizontal tangs of the midspar fitting of the strut to detect discrepancies (cracking, incorrect fastener hole diameter), in accordance with Part 2, “High Frequency Eddy Current (HFEC) Inspection,” of the Accomplishment Instructions of the service bulletin. Accomplish the requirements specified in paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as applicable; and repeat the inspection thereafter at the applicable intervals specified in Table 2, “Reinspection Intervals for Part 2—HFEC Inspection” included in Figure 1 of the service bulletin.

(i) If no cracking is detected and the fastener hole diameter is less than or equal to 0.5322 inch, before further flight, rework the hole in accordance with Part 3 of the Accomplishment Instructions of the service bulletin.

(ii) If no cracking is detected and the fastener hole diameter is greater than 0.5322 inch, before further flight, accomplish the requirements specified in either paragraph (c)(1) or (c)(2) of this AD.

(b) For airplanes on which the two aft-most fasteners have been inspected in accordance with Boeing Service Bulletin 767-54A0101, Revision 1, dated February 3, 2000, prior to May 15, 2001: Perform the initial inspection of the four aft-most fasteners in accordance with paragraph (a) of this AD before the accumulation of 10,000 total flight cycles, or within 1,500 flight cycles after May 15, 2001, whichever occurs later.

Corrective Actions

(c) If any cracking is detected after accomplishment of any inspection required by paragraph (a) of this AD, before further flight, accomplish the requirements specified in either paragraph (c)(1) or (c)(2) of this AD.

(1) Accomplish the terminating action specified in Part 4 of the Accomplishment Instructions of Boeing Service Bulletin 767-54A0101, Revision 1, dated February 3, 2000; or Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002. Accomplishment of this paragraph terminates the requirements of this AD.

(2) Replace the midspar fitting of the strut with a serviceable part, or repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Repeat the applicable inspection thereafter at the applicable time specified in paragraph (a)(1) or (a)(2) of this AD.

(d) If any discrepancies (cracking, incorrect fastener hole diameter) are detected during any inspection required by paragraph (a) of this AD, for which the service bulletin specifies that the manufacturer may be contacted for disposition of those repair conditions: Before further flight, accomplish the corrective actions (including fastener hole rework and/or midspar fitting replacement) in accordance with a method approved by the Manager, Seattle ACO; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

New Requirements of This AD

Additional Inspections

(e) Within 10,000 total flight cycles, or within 600 flight cycles after the effective date of this AD, whichever occurs later: Perform the inspections specified in paragraph (a)(1) or (a)(2) of this AD, as applicable, on all eight aft-most fastener holes or the four forward fastener holes in the group of eight aft-most fastener holes not inspected per paragraph (a)(1), (a)(2), or (b) of this AD. The inspection must be done per the Accomplishment Instructions in Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002. Accomplishment of the applicable inspection on all eight aft-most fastener holes constitutes terminating action for the repetitive inspection requirements of paragraphs (a)(1), (a)(2), and (b) of this AD.

(f) If no cracking or discrepancy is detected during any inspection required by paragraph (e) of this AD: Perform the follow-on actions specified in paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as applicable, per the Accomplishment Instructions in Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002; and repeat the inspections of all eight aft-most fastener holes thereafter at the applicable intervals specified in Table 1 of this AD.

Table 1.—Repetitive Inspection Intervals for All Eight Aft-Most Fastener Holes

If—	Repetitive intervals—
(1) All eight aft-most fastener holes were inspected per paragraph (e) of this AD:	At the applicable intervals specified in Table 1, “Reinspection Intervals for Part 1—Detailed Inspection,” or Table 2, “Reinspection Intervals for Part 2—HFEC Inspection,” as applicable. Both tables are included in Figure 1 of the service bulletin.
(2) Only the four forward fastener holes in the group of eight aft-most fastener holes were inspected per paragraph (e) of this AD:	At the next scheduled repetitive inspection required by paragraph (a)(1) or (a)(2) of this AD, as applicable. Thereafter at the applicable intervals specified in Table 1, “Reinspection Intervals for Part 1—Detailed Inspection,” or Table 2, “Reinspection Intervals for Part 2—HFEC Inspection,” as applicable. Both tables are included in Figure 1 of the service bulletin.

Corrective Actions

(g) If any cracking or discrepancy is detected during any inspection required by paragraph (e) of this AD, before further flight: Accomplish the corrective actions described in paragraph (c) of this AD, per the Accomplishment Instructions in Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002, except as provided in paragraph (d) of this AD.

Service Bulletin Revisions

(h) Accomplishment of the terminating action in paragraph (c)(1) of this AD, per the original release of Boeing Service Bulletin 767-54A0101, dated September 23, 1999; or Revision 2 of Boeing Service Bulletin 767-54A0101, dated January 10, 2002; is acceptable for compliance with the requirements of this AD. However, as of the effective date of this AD, only the actions described in the Accomplishment Instructions of Boeing Service Bulletin 767-54A0101, Revision 3, dated September 5, 2002, should be used.

Inspections Accomplished Per Previous Issue of Service Bulletin

(i) Inspections required by paragraphs (a) and (b) of this AD that are accomplished before the effective date of this AD per Revision 2 of Boeing Service Bulletin 767-54A0101, dated January 10, 2002; or Revision 3 of Boeing Service Bulletin 767-54A0101, dated September 5, 2002; are considered acceptable for compliance with the corresponding action specified in this AD.

Alternative Methods of Compliance

(j) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD.

Issued in Renton, Washington, on December 1, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.