Airworthiness Directives; Boeing Model 767-200, -300, and -300F Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of three existing airworthiness directives (AD), applicable to certain Boeing Model 767-200, -300, and -300F series airplanes. One AD currently requires modification of the nacelle strut and wing structure for certain Boeing Model 767-200, -300, and -300F series airplanes powered by Pratt & Whitney engines. The second AD currently requires a similar modification for certain Boeing Model 767-200, -300, and -300F series airplanes powered by General Electric engines. The third AD currently requires repetitive inspections for cracking of the outboard pitch load fittings of the wing front spar, and corrective action if necessary, for certain Boeing Model 767-200 series airplanes. The third AD also provides a terminating action for the repetitive inspections, which is optional for uncracked pitch load fittings. This proposed AD would require, for airplanes subject to the first and second existing ADs on which certain modifications have been accomplished previously, reworking the aft pitch load fitting, and installing a new diagonal brace fuse pin. This proposed AD also would require, for airplanes subject to the third existing AD, replacing the outboard pitch load fitting of the wing front spar with a new, improved fitting, which would terminate certain currently required repetitive inspections. The actions specified by the proposed AD are intended to prevent fatigue cracking in primary strut structure, which could result in separation of the strut and engine from the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by March 29, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-186-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-186-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 98055-4056; telephone (425) 917-6441; fax (425) 917-6590.

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-186-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-186-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On January 17, 2001, the FAA issued AD 2001-02-07, amendment 39-12091 (66 FR 8085, January 29, 2001), applicable to certain Boeing Model 767-200, -300, and -300F series airplanes powered by Pratt & Whitney engines. On March 22, 2001, we issued AD 2001-06-12, amendment 39-12159 (66 FR 17492, April 2, 2001), applicable to certain Boeing Model 767-200, -300, and -300F series airplanes powered by General Electric engines. Those ADs require modification of the nacelle strut and wing structure. Those actions were prompted by the airplane manufacturer's structural reassessment of the damage tolerance capabilities of Boeing Model 767 series airplanes, which indicated that the actual operational loads on the nacelle strut and wing structure are higher than the analytical loads used during the initial design. Service history and analysis subsequent to this reassessment revealed numerous reports of fatigue cracking of the primary structure that occurred prior to the airplane's reaching its design service objective of 20 years or 50,000 total flight cycles. The requirements of those ADs are intended to prevent fatigue cracking in primary strut structure and consequent reduced structural integrity of the strut.

Later, on April 18, 2001, we issued AD 2001-08-23, amendment 39-12200 (66 FR 21069, April 27, 2001), applicable to certain Boeing Model 767-200 series airplanes. That AD requires repetitive inspections for cracking of the outboard pitch load fittings of the wing front spar, and corrective action if necessary. That AD also provides a terminating action for the repetitive inspections, which is optional for uncracked pitch load fittings. That action was prompted by reports that fatigue cracking of the outboard pitch load fittings on the wing front spar had been found on certain Boeing Model 767-200 series airplanes. The requirements of that AD are intended to find and fix cracking of the outboard pitch load fittings of the wing front spar, which could lead to loss of the upper link load path and result in separation of the strut and engine from the airplane.

Actions Since Issuance of Previous Rules

AD 2001-02-07 cites Boeing Service Bulletin 767-54-0080, dated October 7, 1999; and AD 2001-06-12 cites Boeing Service Bulletin 767-54-0081, dated July 29, 1999; as the appropriate sources of service information for the primary actions required by those ADs. Since the issuance of those ADs, we have received reports that certain parts kits supplied by the airplane manufacturer for the modifications specified in those service bulletins contained bushings for the aft pitch load fitting that were too large in the inner diameter. This discrepancy could cause an excessive gap between the diagonal brace fuse pin and the aft pitch load fitting, which could reduce the life of the fuse pin. Failure of the fuse pin, if not corrected, would result in increased loads in the other wing-to-strut joints, which could result in separation of the strut and engine from the airplane.

With regard to AD 2001-08-23, the preamble to that AD explains that we consider the requirements in that AD “interim action” and that we're considering further rulemaking to require replacing the outboard pitch load fitting of the wing front spar with a new, improved fitting. (AD 2001-08-23 provides for that replacement as an optional terminating action for uncracked pitch load fittings, or as a required terminating action for cracked pitch load fittings.) We now have determined that further rulemaking is indeed necessary, and this proposed AD follows from that determination.

Explanation of Relevant Service Information

We have reviewed and approved Boeing Service Bulletin 767-54-0080, Revision 1, dated May 9, 2002; and 767-54-0081, Revision 1, dated February 7, 2002. Those service bulletins describe procedures similar to those in the original issue of the service bulletins, which are referenced in ADs 2001-02-07 and 2001-06-12. However, for both service bulletins, Revision 1 describes additional work that is necessary for airplanes in certain groups. For airplanes in Groups 4 through 10 in Boeing Service Bulletin 767-54-0080, Revision 1; and in Groups 3 through 12 in Boeing Service Bulletin 767-54-0081, Revision 1; on which the actions in the original issue of the service bulletin were accomplished; the additional work includes installing new markers on the diagonal brace of the left-hand and right-hand struts, reworking the aft load pitch fitting, and installing a new diagonal brace fuse pin. For airplanes in Group 1 of those service bulletins, the additional work includes replacing the outboard pitch load fitting of the wing front spar in accordance with Boeing Service Bulletin 767-57A0070 (described below).

We have reviewed and approved Boeing Service Bulletin 767-57A0070, Revision 3, dated November 8, 2001, which is effective for certain Model 767-200 series airplanes. (AD 2001-08-23 refers to Revision 1 of that service bulletin, dated November 16, 2000, as the appropriate source of service information for the actions required by that AD.) Among other actions, Revision 3 of the service bulletin describes procedures for replacing the outboard pitch load fitting of the wing front spar, on the left- and right-hand sides of the airplane, with a new, improved fitting. Procedures for this replacement include doing a high frequency eddy current (HFEC) inspection for damaged fastener holes, oversizing the fastener holes and repeating the HFEC inspections if necessary, installing an improved outboard pitch load fitting, and machining the outboard pitch load fitting. Boeing Service Bulletin 767-57A0070, Revision 3, refers to Boeing Service Bulletin 767-57-0053 as an appropriate source of service information for additional necessary actions. (Paragraph (b) of AD 2001-02-07 requires, among other actions, accomplishment of the actions specified in Boeing Service Bulletin 767-57-0053, Revision 2, dated September 23, 1999.)

We have also reviewed and approved Boeing Service Bulletin 767-29-0057, Revision 1, dated August 14, 2003. (Paragraph (b) of AD 2001-02-07 and paragraph (b) of AD 2001-06-12 refer to the original issue of that service bulletin, dated December 16, 1993; as an acceptable source of service information for certain actions required to be accomplished prior to or concurrently with the modification of the nacelle strut and wing structure required by paragraph (a) of those ADs.) Revision 1 of the service bulletin describes procedures for changing wire bundle routing and improving wire bundle support to ensure that there is sufficient separation between wire bundles and hydraulic tubes in the aft fairing area of the strut. These procedures are essentially the same as those described in the original issue of the service bulletin. Thus, we have revised paragraph (b) (under the heading “Requirements of AD 2001-02-07”) and paragraph (e) (under the heading “Requirements of AD 2001-06-12”) in this proposed AD to refer to Boeing Service Bulletin 767-29-0057, Revision 1, as an acceptable source of service information for the applicable actions required by those paragraphs.

We have also reviewed and approved Boeing Service Bulletin 767-54A0094, Revision 2, dated February 7, 2002. (Paragraph (b) of AD 2001-02-07 and paragraph (b) of AD 2001-06-12 refer to Revision 1 of that service bulletin, dated September 16, 1999; as an acceptable source of service information for certain actions required to be accomplished prior to or concurrently with the modification of the nacelle strut and wing structure required by paragraph (a) of those ADs.) Revision 2 of the service bulletin describes procedures for a detailed visual inspection for cracking of the forward and aft lugs of the diagonal brace, and follow-on actions. There are no substantial differences between the procedures in Revisions 1 and 2 of the service bulletin. Thus, we have revised paragraph (b) (under the heading “Requirements of AD 2001-02-07”) and paragraph (e) (under the heading “Requirements of AD 2001-06-12”) in this proposed AD to refer to Boeing Service Bulletin 767-54A0094, Revision 2, as an acceptable source of service information for the applicable actions required by that paragraph.

Accomplishment of the actions specified in Boeing Service Bulletins 767-54-0080, Revision 1, and 767-57A0070, Revision 3, along with the other service bulletins specified in AD 2001-02-07, is intended to adequately address the identified unsafe condition.

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 ADs 2001-02-07 and 2001-06-12 to continue to require modification of the nacelle strut and wing structure. For certain airplanes on which certain modifications have been accomplished previously, the proposed AD would require reworking the aft load pitch fitting, and installing a new diagonal brace fuse pin. The proposed AD also would supersede AD 2001-08-23 to continue to require repetitive inspections for cracking of the outboard pitch load fittings of the wing front spar, and corrective action if necessary. For certain airplanes, the proposed AD would require replacing the outboard pitch load fitting of the wing front spar with a new, improved fitting on the left- and right-hand sides of the airplane, which would terminate the repetitive inspections required by AD 2001-08-23. Except as discussed below under the heading “Differences Between Proposed AD and Service Bulletins,” the actions would be required to be accomplished in accordance with the service bulletins described previously in this proposed AD, as well as other service bulletins that were referenced in ADs 2001-02-07 and 2001-06-12.

Differences Between Proposed AD and Service Bulletins

Although the Accomplishment Instructions of Revision 1 of Boeing Service Bulletins 767-54-0080 and 767-54-0081 specify installing new markers on the diagonal brace of the left-hand and right-hand struts, the proposed AD would not require such installation. We find that not installing such markers will not affect safety of flight for the affected airplane fleet.

Paragraphs (k) and (l) of this proposed AD specify an inspection to determine the part number of the aft pitch load fitting. While Revision 1 of Boeing Service Bulletins 767-54-0080 and 767-54-0081 state that rework of the aft pitch load fitting is not necessary if an aft pitch load fitting was reworked previously, those service bulletins do not provide for determining the part number of the aft pitch load fitting. We find that an inspection is the best method for operators to use to determine the part number of the aft load pitch fitting.

Explanation of Changes to Existing Requirements

For clarification, we have revised all references to “Boeing Model 767 series airplanes” from ADs 2001-02-07 and 2001-06-12 to refer more specifically to Boeing Model 767-200, -300, and -300F series airplanes. Boeing Model 767-400ER series airplanes are not subject to these ADs.

For clarity, we have revised paragraph (b) of this proposed AD, under the heading “Requirements of AD 2001-02-07,” to remove a reference to page 8 of Boeing Service Bulletin 767-54-0080. Similarly, we have revised paragraphs (d)(1) and (e) of this proposed AD, under the heading “Requirements of AD 2001-06-12,” to remove references to pages 8 and 54 of Boeing Service Bulletin 767-54-0081.

Paragraph (b) of AD 2001-02-07 states that accomplishment of that paragraph constitutes terminating action for AD 99-07-06, amendment 39-11091 (64 FR 14578, March 26, 1999). AD 99-07-06 has been superseded by AD 2000-07-05, amendment 39-11659 (65 FR 18883, April 10, 2000). Therefore, we have revised paragraph (b) of this proposed AD to refer to AD 2000-07-05 instead of AD 99-07-06.

Similarly, we have revised paragraph (b) of this proposed AD to note that accomplishment of that paragraph constitutes terminating action for AD 2000-12-17, amendment 39-11795 (65 FR 37843, June 19, 2000). AD 2000-12-17 requires accomplishment of the actions specified in Boeing Service Bulletin 767-57-0053, Revision 2, and paragraph (g) of that AD states that modification of the nacelle strut and wing structure in accordance with Boeing Service Bulletin 767-54-0080 constitutes terminating action for the actions required by AD 2000-12-17. A reference to AD 2000-12-17 would have been appropriate in AD 2001-02-07 but was inadvertently omitted.

Also, we have revised the cost impact estimate in this proposed AD for the actions specified in Boeing Service Bulletin 767-54-0080 and 767-54-0081. These changes are due in part to increases in the work hour estimates in that service bulletin. For the actions in Boeing Service Bulletin 767-54-0080, the revision of the cost impact estimate is due to our determination that, in this case, it is appropriate to include time for gaining access and closing up in the cost impact estimate. While cost impact figures in AD actions typically do not include incidental costs such as the time required to gain access and close up, we find that certain actions associated with gaining access to perform the actions that would be required by this proposed AD (e.g., removing engines, draining fuel) would not ordinarily be accomplished if this proposed AD were not adopted. (AD 2001-06-12 already includes time for gaining access and closing up in the cost impact estimate for the actions associated with Boeing Service Bulletin 767-54-0081.)

Cost Impact

There are approximately 619 airplanes of the affected design in the worldwide fleet. The FAA estimates that 255 airplanes of U.S. registry would be affected by this proposed AD.

The following table shows the estimated costs associated with the actions currently required by ADs 2001-02-07, 2001-06-12, and 2001-08-23, at an average labor rate of $65 per work hour:

For affected airplanes, the new inspection to determine the part number of the aft load pitch fittings 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 this proposed requirement is estimated to be $65 per airplane.

For affected airplanes, the new replacement of the outboard pitch load fittings that is proposed in this AD action would take approximately 14 work hours per airplane to accomplish, at an average labor rate of $65 per work hour. Required parts would cost approximately $14,438 per airplane. Based on these figures, the cost impact of this proposed requirement is estimated to be $15,348 per airplane.

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; however, as explained previously, time to gain access and close up has been included for certain actions in this proposed AD.

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.