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Proposed Rule

Airworthiness Directives; Boeing Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F Series Airplanes

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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 all Boeing Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series airplanes, that currently requires repetitive inspections to find cracking of the lower skin panel at the lower row of fasteners in certain lap joints of the fuselage, and repair, if necessary. This action would limit the applicability of the existing AD; add certain repetitive inspections; revise certain compliance times; and add certain modifications. This proposal is prompted by the FAA's determination that, in light of additional crack findings, certain modifications of the fuselage lap joints are necessary. The actions specified by the proposed AD are intended to find and fix fatigue cracking of the fuselage lap joints, which could result in sudden fracture and failure of the lower skin lap joints, and rapid decompression of the airplane.

DATES:

Comments must be received by August 27, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-105-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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. 99-NM-105-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 for Windows 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.

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FOR FURTHER INFORMATION CONTACT:

Walt Sippel, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2774; fax (425) 227-1181.

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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 99-NM-105-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. 99-NM-105-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On February 10, 1999, the FAA issued AD 99-04-22, amendment 39-11047 (64 FR 7774, February 17, 1999), applicable to all Boeing Model 727, 727-100, 727-200, 727C, 727-100C, and 727-200F series airplanes, to require repetitive inspections to find cracking of the lower skin panel at the lower row of fasteners in certain lap joints of the fuselage, and repair, if necessary. That AD also provides for optional terminating action for certain repetitive inspections. That action was prompted by a report of fatigue cracking in the lower skin panel at the lower row of fasteners of the fuselage lap joints. The requirements of that AD are intended to find and fix such fatigue cracking, which could result in sudden fracture and failure of the lower skin lap joints, and rapid decompression of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of AD 99-04-22, the FAA has received additional reports of fatigue cracking in the lower skin of the lap joints of the fuselage on Model 727 series airplanes that had accumulated as few as 36,781 total flight cycles, and several airplanes that had accumulated more than 50,000 flight cycles. The airplanes having more than 50,000 flight cycles were previously inspected per that AD. Further investigation revealed additional cracking and corrosion in various areas of the crown skin lap joints at the fastener locations. The majority of the cracks occurred at left and right stringers 4 and 26. The FAA finds that this damage can occur at those stringer locations between 30,000 and 50,000 flight cycles. These cracks are not always detectable using the external inspection procedures required by AD 99-04-22, and can link up with adjacent cracks causing multiple site damage, which can result in a rapid decompression of the fuselage.

Based on these findings, the FAA has determined that the current repetitive external detailed visual inspection procedures required by AD 99-04-22 are not adequate for finding cracks in these locations. Therefore, the FAA finds that additional rulemaking is necessary to require accomplishment of certain lap joint modifications and pre-and post-mod inspections, instead of the repetitive external detailed visual inspections. Start Printed Page 36517

Supplemental Type Certificate (STC) Holders

The FAA has determined that approximately half of the airplanes specified in the applicability of this proposed rule have been modified from a passenger configuration to an all-cargo configuration. The FAA has approved several service bulletins (listed below) that could be approved as alternative methods of compliance for the proposed modification requirements, but based on the number of affected airplanes, will instead be included in the proposed rule. The holders of STCs for these modified airplanes have developed these service bulletins to address modification/repair of the longitudinal lap joints in the area of the cargo door doubler only, but all other applicable areas also must be inspected and modified per Boeing Service Bulletin 727-53A0222, Revision 1, dated March 15, 2001.

Public Meeting

A joint FAA and Boeing meeting was held on July 25-27, 2000, to inform industry of the activity on Boeing Model 727 and 737 fuselage lap joints. Others in attendance were representatives from STC holders, air carriers, and repair stations, as well as Principal Maintenance Inspectors (PMI) from the FAA's Flight Standards Service. The objective of the meeting was to provide an overview of the FAA rulemaking process; discuss the recommendations of Boeing Service Bulletins 727-53A0222 and 737-53A1177, including background information; standardize the 727 and 737 service bulletins, where possible; and discuss the impact that the recommended service bulletin modifications would have on industry.

During the meetings, holders of certain STCs presented information pertaining to service bulletin activity for those airplanes that have been modified from a passenger to an all-cargo configuration. The meeting accomplished the objective of exchanging information between the FAA, Boeing, and industry on various aspects of Boeing Models 727 and 737 fuselage lap joints, including compliance planning. As a result of the meeting, attendees recognized the importance of modifying certain lap joints before reaching the point of widespread fatigue damage. Suggestions to improve the service bulletins and clarify AD compliance issues were made by operators and PMIs, and have been incorporated into the service bulletins and the proposed ADs discussed below. The minutes of the meeting have been placed in the public docket.

Explanation of Relevant Service Information

In addition to Boeing Service Bulletin 727-53A0222, Revision 1, the FAA has approved four service bulletins for STCs that modify affected airplanes from a passenger to an all-cargo configuration. These service bulletins address the areas of the lap joints that are physically externally covered by the addition of large doublers in the area of the cargo door. These doublers affect the loads in the lap joints, and for this reason the STC service bulletins provide inspections and modification instructions for those lap joint areas covered by the doublers.

The FAA has reviewed and approved the following service bulletins:

Service BulletinDate
Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix AMarch 15, 2001.
Aeronautical Engineers Inc., Service Bulletin AEI 00-01, Revision AMay 7, 2001.
PEMCO World Air Services Bulletin 727-53-0007, Revision 1June 6, 2001.
Aircraft Technical Service, Inc., Service Bulletin ATS 727-001May 7, 2001.
Federal Express Corporation Service Bulletin 00-029, Revision AMay 16, 2001.

The Boeing Service Bulletin describes, but is not limited to, the following procedures:

  • Either a Low Frequency Eddy Current (LFEC) or internal detailed visual and Medium Frequency Eddy Current (MFEC) inspection for cracking of the lower row of fasteners in the lower skin of fuselage sections 41, 43, and 46 of the lap joints.
  • A High Frequency Eddy Current (HFEC) inspection of the fastener holes to verify crack indications if cracks are found during the LFEC inspection; or accessing the inboard side of the skin to do an MFEC inspection of the lower row of fasteners for verification of cracking in the lower skin.
  • After crack indications are verified: An internal detailed visual inspection and an MFEC inspection for damage of the entire skin panel of the lap joint.
  • Repair of the damage per the structural repair manual if the damage is within one bay. And
  • Modification of the fuselage lap joints, and a post-modification inspection for cracking in the skin. The modification consists of cutting out the lap joint for the entire skin panel and installing an external doubler and tripler at stringers S-4L, S-4R, and S-26L.

The STC service bulletins listed above describe procedures for a one-time pre-modification inspection for cracking of the lower row of fasteners in the lower skin of the lap joint, modification of the surrounding structure of the main cargo door and doublers, and repetitive post-modification HFEC inspections for cracking in the cargo door area. This is to be done concurrent with the modification of the fuselage lap joints specified in the Boeing service bulletin described above.

Accomplishment of the actions specified in the service bulletins 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 AD 99-04-22 to continue to require certain repetitive inspections to find cracking of the lower skin panel at the lower row of fasteners in certain lap joints of the fuselage, and repair, if necessary. The proposed AD also would limit the applicability; add certain repetitive inspections; revise certain compliance times; and add certain modifications. The actions would be required to be accomplished per the service bulletins described previously, except as discussed below.

Differences Between the Boeing Service Bulletin and This Proposed AD

The FAA recognizes that the lap joint modification specified in this proposed AD would require jacking, shoring, removing interior components, and modifying certain lap joints, which would require taking the airplane out of service for as much as 22 days. This lengthy shop visit, as well as the relatively short compliance time required to accomplish this proposed AD, make it necessary for operators to engage in compliance planning to ensure that, when the deadline for compliance arrives, all of the required actions have been completed on all affected airplanes. Therefore, paragraph (c) of this proposed AD would require that operators submit to the FAA a compliance plan within 3 months after the effective date of this AD. This will enable the FAA to verify that all operators will be able to meet the deadlines imposed by this proposed AD.

While the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this proposal would require Start Printed Page 36518that the repair of those conditions be accomplished per a method approved by the FAA, or per 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 Aircraft Certification Office, to make such findings.

Cost Impact

There are approximately 900 Model 727 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 700 airplanes of U.S. registry would be affected by this proposed AD.

The inspections that are currently required by AD 99-04-22 take approximately 8 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $480 per airplane.

The FAA estimates that the inspections proposed by this NPRM will impose the following costs, given an average labor rate of $60 per work hour:

Service information & inspection methodWork hoursCosts per inspection cycle
Boeing SB 727-53A0222—External LFEC16$960
Boeing SB 727-53A0222—Internal Detailed Visual and MFEC (Passenger Airplanes)1207,200
Boeing SB 727-53A0222—Internal Detailed Visual and MFEC (Cargo Airplanes)402,400
AEI SB 00-0112720
PEMCO SB 727-53-000712720
ATS SB 727-00112720
Federal Express SB 00-02912720

The FAA estimates that, during the 10-year period after issuance of the proposed AD, worldwide operators will be required to modify 360 Model 727 series airplanes. The modification required by the proposed AD would take approximately 1,200 work hours to accomplish, at an average labor rate of $60 per work hour. The worldwide cost impact of the required modification is estimated to be $37,413,000 over 10 years, or an average of $3,741,000 per year. The highest impact year is the first year after issuance of the AD; an estimated 56 Model 727 series airplanes would require modification in that year. The affected Model 727 airplanes operated by U.S. operators comprise approximately 78 percent of the total worldwide costs. Therefore, the highest cost impact of the modification in any given year is estimated to be $4,527,000 for U.S. operators.

The compliance plan that is proposed in this AD action would take approximately 24 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the compliance plan on U.S. operators is estimated to be $1,008,000, or $1,440 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.

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.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. Section 39.13 is amended by removing amendment 39-11047 (64 FR 7774, February 17, 1999), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 99-NM-105-AD. Supersedes AD 99-04-22, amendment 39-11047.

Applicability: Model 727 series airplanes, as listed in Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix A, dated March 15, 2001, certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance per paragraph (l)(1) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To find and fix fatigue cracking in the lower skin panel at the lower row of fasteners of the fuselage lap joints, which could result in sudden fracture and failure of the lap joints, and rapid decompression of the airplane; accomplish the following: Start Printed Page 36519

Repetitive Inspections

(a) Do either an external low frequency eddy current (LFEC) inspection to find cracking, or both internal detailed visual and medium frequency eddy current (MFEC) inspections to find cracking or corrosion in the lower skin panels of the lower row of fasteners of the fuselage lap joints at the earlier of the times specified in paragraphs (a)(1) and (a)(2) of this AD on lap joints identified in Tables A through H and J through N; per Paragraph 1., Planning Information, of Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix A, dated March 15, 2001. Except as provided by paragraph (b) of this AD, after doing the applicable initial inspection, repeat that inspection at the intervals specified in Tables A through G or J through N of the service bulletin, as applicable.

(1) At the latest of the times specified for the initial inspection in Tables A through H (for Groups 1, 2, 3, and 5 airplanes), or Tables J through N (for Groups 3 and 4 airplanes), as applicable, of Section 1.E. “Compliance,” of the service bulletin, except where the compliance time in the service bulletin specifies a compliance time interval based on “the release of this service bulletin,” this AD requires compliance within the interval specified in the service bulletin “after the effective date of this AD.”

(2) Within 600 flight cycles after the last LFEC inspection or 7,000 flight cycles after the last HFEC inspection, if any, is accomplished in accordance with AD 99-04-22, amendment 39-11047.

Note 2:

Groups 1-5 are defined in the effectivity section of the service bulletin.

(b) The repetitive inspection intervals for lap joints identified in Table H of Paragraph 1., Planning Information, of Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix A, dated March 15, 2001, decrease with increasing flight cycles. Perform the repetitive inspections listed in Table H of the service bulletin at the following thresholds and intervals:

(1) If, at the time of the most recent inspection required by paragraph (a) or (b) of this AD, the airplane has accumulated fewer than 35,000 total flight cycles: Perform LFEC inspections at intervals not to exceed 600 flight cycles, or detailed internal visual and MFEC inspections at intervals not to exceed 7,000 flight cycles.

(2) If, at the time of the most recent inspection required by paragraph (a) or (b) of this AD, the airplane has accumulated 35,000 or more, but fewer than 45,000 flight cycles: Perform LFEC inspections at intervals not to exceed 600 flight cycles, or detailed internal visual and MFEC inspections at intervals not to exceed 7,000 flight cycles.

(3) If, at the time of the most recent inspection required by paragraph (a) or (b) of this AD, the airplane has accumulated 45,000 or more, but fewer than 54,999 flight cycles: Perform detailed internal visual and MFEC inspections at intervals not to exceed 2,000 flight cycles.

(4) If, at the time of the most recent inspection required by paragraph (a) or (b) of this AD, the airplane accumulated 55,000 or more total flight cycles: Perform LFEC inspections at intervals not to exceed 300 flight cycle intervals.

Note 3:

For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to find 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.”

Compliance Plan

(c) Within 3 months after the effective date of this AD, submit a plan to the FAA identifying a schedule for compliance with paragraph (d) of this AD. This schedule must include, for each of the operator's affected airplanes, the dates and maintenance events (e.g., letter checks) when the required actions will be accomplished. For the purposes of this paragraph, “FAA” means the Principal Maintenance Inspector (PMI) for operators that are assigned a PMI, or the cognizant Flight Standards District Office for other operators. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

Note 4:

Operators are not required to submit revisions to the compliance plan required by paragraph (c) of this AD to the FAA.

Modification/Inspections

(d) For Model 727-200 series airplanes: Accomplish the modification listed in Table H of Paragraph 1., Planning Information, of Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix A, dated March 15, 2001, at the threshold in paragraph (d)(1), (d)(2), or (d)(3) of this AD, as applicable. Within 35,000 flight cycles after doing the modification, do the post-modification inspection for cracking in the skin, per Part III of the Accomplishment Instructions of the service bulletin:

(1) For airplanes that have accumulated less than 35,000 total flight cycles on the effective date of the AD: Accomplish the modification prior to 48,000 total flight cycles.

(2) For airplanes that have accumulated between 35,000 and 54,999 total flight cycles on the effective date of the AD: Accomplish the modification prior to 55,000 total flight cycles, or within 2,000 total flight cycles of the effective date of this AD.

(3) For airplanes that have accumulated 55,000 or greater total flight cycles on the effective date of the AD: Accomplish the modification within 2,000 flight cycles after the effective date of this AD.

Repair

(e) If any cracking or corrosion is found during any inspection required by paragraph (a), (b), or (d) of this AD: Before further flight, repair per Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix A, dated March 15, 2001. Where the service bulletin specifies to contact Boeing for repair instructions, repair per a method approved by the Manager, Seattle ACO; or per data meeting the type certification basis of the airplane approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD.

Concurrent Modifications

(f) For Model 727-200 series airplanes modified per supplemental type certificate (STC) SA1368SO or SA1797SO: Concurrent with the modification of the fuselage lap joints required by paragraph (d) of this AD, do the inspection for cracking of the lower row of fasteners in the lower skin of the lap joints, and the modification specified in Aeronautical Engineers Inc., Service Bulletin AEI 00-01, Revision A, dated May 7, 2001, per the service bulletin.

(g) For Model 727-200 series airplanes modified per STC SA1444SO and SA1509SO: Concurrent with the modification of the fuselage lap joints required by paragraph (d) of this AD, do the inspection for cracking of the lower row of fasteners in the lower skin of the lap joints, and the modification specified in PEMCO World Air Services Bulletin 727-53-0007, Revision 1, dated June 6, 2001, per the service bulletin.

(h) For Model 727-200 series airplanes modified per STC SA00015AT: Concurrent with the modification of the fuselage lap joints required by paragraph (d) of this AD, do the inspection for cracking of the lower row of fasteners in the lower skin of the lap joints, and the modification specified in Aircraft Technical Service, Inc., Service Bulletin ATS 727-001, dated May 7, 2001, per the service bulletin.

(i) For Model 727-200 series airplanes modified per STC SA176SO: Concurrent with the modification of the fuselage lap joints required by paragraph (d) of this AD, do the inspection for cracking of the lower row of fasteners in the lower skin of the lap joints, and the modification specified in Federal Express Corporation Service Bulletin 00-029, Revision A, dated May 16, 2001, per the service bulletin.

(j) Within 2,200 flight cycles after doing the applicable modification specified in paragraph (f), (g), (h), or (i) of this AD, do the post-modification inspection for cracking in the skin per the applicable service bulletin specified in Table 1, below. Repeat the applicable inspection after that at intervals not to exceed 2,200 flight cycles. Table 1 follows:

Table 1

Service BulletinDate
(1) Aeronautical Engineers Inc., Service Bulletin AEI 00-01, Revision AMay 7, 2001.
(2) PEMCO World Air Services Bulletin 727-53-0007, Revision 1June 6, 2001.
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(3) Aircraft Technical Service, Inc., Service Bulletin ATS 727-001May 7, 2001.
(4) Federal Express Corporation Service Bulletin 00-029, Revision AMay 16, 2001.

Repair

(k) If any cracking is found during any inspection required by paragraph (f), (g), (h), or (i) of this AD: Before further flight, repair per the applicable service bulletin as provided in Table 1 in paragraph (j) of this AD. Where cracks exceed the limits provided in the service bulletin, and the bulletin specifies to contact the provider of the service bulletin for repair instructions, prior to further flight, repair per a method approved by the Manager, Seattle ACO. If any cracking is found is during any inspection required by paragraph (j) of this AD: Before further flight, repair per a method approved by the Manager, Seattle ACO. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD.

Alternative Methods of Compliance

(l)(1) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA PMI, who may add comments and then send it to the Manager, Seattle ACO.

(2) Alternative methods of compliance, approved previously per AD 99-04-22, amendment 39-11047, are approved as alternative methods of compliance with this AD.

Note 5:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(m) Special flight permits may be issued per sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Start Signature

Issued in Renton, Washington, on July 6, 2001.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 01-17433 Filed 7-11-01; 8:45 am]

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