Airworthiness directives: Boeing,
[Federal Register: April 15, 2003 (Volume 68, Number 72)]
[Proposed Rules]
[Page 18170-18173]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15ap03-29]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2000-NM-376-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 Series Airplanes Equipped With Rolls Royce RB211 Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of comment period.
SUMMARY: This document revises an earlier proposed airworthiness directive (AD), applicable to certain Boeing Model 757 series airplanes equipped with Rolls Royce RB211 engines, that would have superseded an existing AD that currently requires modification of the nacelle strut and wing structure. The proposed AD would have added a one-time inspection of the middle gusset of the inboard side load fitting for proper alignment, and a one-time inspection of certain fastener holes in the lower spar fitting of the nacelle strut and wing structure for cracking, and corrective actions, if necessary. For certain airplanes, the proposed AD would have required installation of new fasteners. This new action revises the proposed rule by reducing a certain compliance time and adding new inspections. The actions specified by this new proposed AD are intended to prevent fatigue cracking in primary strut structure and consequent reduced structural integrity of the strut. These actions are intended to address the identified unsafe condition.
DATES: Comments must be received by May 12, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-376-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. 2000-NM-376-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.
FOR FURTHER INFORMATION CONTACT: Dennis Stremick, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6450; 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:
[sbull] 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.
[sbull] For each issue, state what specific change to the proposed AD is being requested.
[sbull] 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 2000-NM-376-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. 2000-NM-376-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Boeing Model 757 series airplanes equipped with Rolls Royce RB211 engines, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on January 4, 2002 (67 FR 547). That NPRM proposed to supersede AD 99-24-07, amendment 39-11431 (64 FR 66370, November 26, 1999), which is applicable to certain Boeing Model 757 series airplanes equipped with Rolls Royce RB211 engines. That NPRM would have continued to require modification of the nacelle strut and wing structure. That NPRM would also have added a one-time inspection of the middle gusset of the inboard side load fitting for proper alignment, and a one-time inspection of certain fastener holes in the lower spar fitting of the nacelle strut and wing structure for cracking, and corrective actions, if necessary. For certain airplanes, that NPRM would have required installation of new fasteners. Fatigue cracking in primary strut structure could result in reduced structural integrity of the strut.
Actions Since Issuance of Previous Proposal
Since the issuance of that NPRM, the FAA has reviewed and approved Boeing Service Bulletin 757-54-0035, Revision 2, dated June 13, 2002, including Evaluation Form. The procedures in this service bulletin are similar to those in Boeing Service Bulletin 757-54-0035, Revision 1, dated April 15, 1999, which was referenced as the appropriate source of service information for the actions required by the original NPRM. However, Revision 2 reduces the compliance time for the detailed inspection of the middle gusset for airplanes that have not yet accumulated 50,000 total flight cycles. The new compliance time for the inspection is before the accumulation of 50,000 total
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flight cycles or within 15,000 flight cycles after doing the modification required by AD 99-24-07, whichever is earlier.
Comments
Due consideration has been given to the comments received in response to the NPRM. One commenter has no technical objection to the NPRM, but does not agree that the proposed inspections are necessary to ensure the continued airworthiness of the engine strut. Another commenter does not own or operate the affected airplanes.
Request To Change Paragraph (b)
One commenter, the manufacturer, states that there are airplanes in service that are many years away from the compliance threshold for the inspections specified in paragraph (b) of the NPRM. The commenter adds that those airplanes will not receive timely inspections of the lower spar fitting/aft bulkhead fasteners within the compliance time of 15,000 total flight cycles or 6 months after the effective date of the AD, whichever is later, as specified in paragraph (b). The commenter asks that paragraph (b) be changed to reduce the compliance time for those airplanes in order to ensure that the inspections are done in a timely manner.
We agree with the commenter. The manufacturer has provided data which show that the compliance time specified in Revision 1 of the service bulletin is not adequate to preclude an unsafe condition of loose or missing fasteners in the aft bulkhead of the lower spar fitting before the airplane reaches 50,000 total flight cycles. Also, we have approved Revision 2 of the referenced service bulletin, as stated above, in which the manufacturer recommends reducing the compliance time for airplanes that have not yet accumulated 50,000 total flight cycles. We have added a detailed inspection for loose or missing fasteners, and reduced the compliance time for the inspection specified in Revision 2 of the service bulletin (before the accumulation of 50,000 total flight cycles or within 15,000 flight cycles after doing the modification, whichever is first) to specify the compliance time as ``before the accumulation of 15,000 total flight cycles or within 6 months after the effective date of the AD, whichever is first.''
Request To Delete the Word ``Midchord''
One commenter asks that all references to the word ``midchord'' be deleted from the NPRM. The commenter notes that the midchord is not part of the inspection area specified in the referenced service bulletin.
We agree with the commenter and have removed all references to the word ``midchord'' from the supplemental NRPM.
Request To Clarify Service Information
One commenter states that Revision 1 of the referenced service bulletin was added to paragraph (a), ``Restatement of Requirements of AD 99-24-07,'' of the original NPRM as an additional source of service information for doing the modification required by that paragraph. The commenter notes that Revision 1 was not specified in the original requirements of AD 99-24-07. However, the commenter does not ask for any change to the NPRM.
We agree that Revision 1 of the service bulletin was not in the original requirements of AD 99-24-07. The paragraph titled ``Actions Since Issuance of Previous Rule,'' in the preamble of the NPRM, provides an explanation of the reason Revision 1 was added: It describes new procedures for an examination of the middle gusset of the inboard side load fitting to determine if the angle between the middle gusset and the outboard face of the lug is out of alignment. If the angle is out of alignment, the corrective action involves machining the middle gusset to the specified angle. For operators that already did the modification, the original issue of the service bulletin is carried over from AD 99-24-07 into paragraph (a) of the supplemental NPRM.
Request To Change Paragraph (b)(2)(ii)
One commenter states that the actions proposed by paragraph (b)(2)(ii) of the NPRM are to be accomplished even if a repair has been installed, due to cracking found per the inspection proposed by paragraph (b)(2) of the NPRM. The commenter notes that this may lead operators to alter repairs previously approved by the Manager of the Seattle Aircraft Certification Office (ACO), per paragraph (b)(2)(i) of the NPRM. The commenter adds that this would require operators to obtain approvals for alternative methods of compliance per paragraph (c)(1) of the NPRM. The commenter states that this may cause redundant work and would consume valuable resources at both the airline and the FAA. The commenter asks that paragraph (b)(2)(ii) of the NPRM be separated into two paragraphs, one for repaired holes and one for holes with no cracking.
We do not agree with the commenter. If a repair was done per a previous approval by the Manager of the Seattle ACO, paragraph (b)(2)(ii) of this AD (now added to paragraph (e) of the supplemental NPRM) must still be done. The actions specified in Revision 2 of the service bulletin increase the diameter of the fastener holes specified in Revision 1 of the service bulletin, therefore, we do not agree to further change paragraph (e) of this supplemental NPRM.
Explanation of Changes Made to NPRM
We have changed the service bulletin citation throughout this supplemental NPRM to exclude the Evaluation Form. The form is intended to be completed by operators and submitted to the manufacturer to provide input on the quality of the service bulletin; however, this AD does not include such a requirement.
We have changed all references to ``detailed visual inspection'' in the NPRM to ``detailed inspection'' in this supplemental NPRM.
In addition, although Revision 2 of the service bulletin specifies an inspection of only 14 aft bulkhead fasteners, paragraph (b) of this supplemental NPRM requires inspection of all 20 aft bulkhead fasteners. Further, the service bulletin specifies an inspection of only 2 fasteners of the lower spar fitting located in Panel 7 at Location 37, but this supplemental NPRM requires inspection of all 8 fasteners, as clarified in Notes 2 and 4.
Revision 2 also specifies that operators can use tools of their own design as alternatives to Boeing-supplied tools when doing the actions specified in the service bulletin. Paragraph (a) of this supplemental NPRM prohibits the use of such tools, except those specified in Figures 3 and 5 of the Accomplishment Instructions of Revision 2 of the service bulletin.
Conclusion
Since these changes expand the scope of the originally proposed rule, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.
Cost Impact
There are approximately 394 airplanes of the affected design in the worldwide fleet. The FAA estimates that 176 airplanes of U.S. registry would be affected by this proposed AD.
The modification that is currently required by AD 99-24-07 takes approximately 1,049 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. This work hour figure includes the time it
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will take to remove and reinstall the struts from the airplane as well as the time required to gain and close access to the adjacent wing structure. Based on these figures, the cost impact of the currently required modification on U.S. operators is estimated to be $11,077,440, or $62,940 per airplane.
This cost impact figure does not reflect the cost of the terminating actions described in the service bulletins listed in paragraph I.C., Table I, ``Strut Improvement Bulletins,'' on page 6 of Boeing Service Bulletin 757-54-0035, that are required to be accomplished prior to, or concurrently with, the modification of the nacelle strut and wing structure. Since some operators may have accomplished certain modifications on some or all of the airplanes in the fleet, while other operators may not have accomplished any of the modifications on any of the airplanes in the fleet, the FAA is unable to provide a reasonable estimate of the cost of accomplishing the terminating actions described in the service bulletins listed in Table I of the service bulletin.
It would take approximately 1 work hour per airplane to accomplish the new detailed inspection of the middle gusset, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD is estimated to be $10,560, or $60 per airplane.
It would take approximately 8 work hours per airplane to accomplish the new fastener removal and eddy current inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the removal and inspection proposed by this AD is estimated to be $84,480, or $480 per airplane.
The cost impact figures discussed above are 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 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
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
-
Section 39.13 is amended by removing amendment 39-11431 (64 FR 66370, November 26, 1999), and by adding a new airworthiness directive (AD), to read as follows:
Boeing: Docket 2000-NM-376-AD. Supersedes AD 99-24-07, Amendment 39- 11431.
Applicability: Model 757 series airplanes equipped with Rolls Royce engines, line numbers 1 through 735 inclusive; 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 in accordance with paragraph (h)(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 prevent fatigue cracking in primary strut structure and consequent reduced structural integrity of the strut, accomplish the following:
Restatement of Requirements of AD 99-24-07
Modification
(a) Modify the nacelle strut and wing structure according to Boeing Service Bulletin 757-54-0035, dated July 17, 1997; or Revision 1, dated April 15, 1999; at the later of the times specified in paragraph (a)(1) or (a)(2) of this AD. All of the terminating actions described in the service bulletins and listed in paragraph I.C., Table I, ``Strut Improvement Bulletins,'' on page 6 of Boeing Service Bulletin 757-54-0035, and on page 7 of Revision 1 of the service bulletin, as applicable, must be accomplished according to those service bulletins prior to, or concurrently with, the accomplishment of the modification of the nacelle strut and wing structure required by this paragraph. After the effective date of this AD, use only Revision 1 of the service bulletin.
(1) Prior to the accumulation of 37,500 total flight cycles, or prior to 20 years since the date of manufacture of the airplane, whichever occurs first.
(2) Within 3,000 flight cycles after January 3, 2000 (the effective date of AD 99-24-07, amendment 39-11431).
New Requirements of This AD
Inspections/Corrective Actions
(b) For airplanes on which the modification required by paragraph (a) of this AD has not been done according to Boeing Service Bulletin 757-54-0035, dated July 17, 1997: Before the accumulation of 15,000 total flight cycles, or within 6 months after the effective date of this AD, whichever is later, do a detailed inspection of the 20 aft bulkhead fasteners of the lower spar fitting for loose or missing fasteners, according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Before further flight, replace any loose or missing fasteners with new fasteners according to Boeing Service Bulletin 757-54-0035, Revision 1, dated April 15, 1999; or Revision 2, dated June 13, 2002, excluding Evaluation Form. Repeat the inspection after that at least every 6 months.
Note 2: The 20 aft bulkhead fasteners are located in Panel 7 at Locations 36, 37, and 41. The number of fasteners at Location 37 has increased from 2 to 8 fasteners. Figure 30 of Boeing Service Bulletin 757-54-0035, Revision 2, dated June 13, 2002, illustrates the location of the fasteners.
Note 3: 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
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the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.''
(c) For airplanes on which the modification required by paragraph (a) of this AD has been done according to Boeing Service Bulletin 757-54-0035, dated July 17, 1997: Within 15,000 flight cycles after doing the modification required by paragraph (a) of this AD, or within 3 years after the effective date of this AD, whichever is later; do a one-time detailed inspection of the middle gusset of the inboard side load fitting for proper alignment, according to Part II of the Accomplishment Instructions of Boeing Service Bulletin 757-54-0035, Revision 1, dated April 15, 1999; or Revision 2, dated June 13, 2002, excluding Evaluation Form. If the gusset is not aligned properly, before further flight, machine the gusset to the specified angle according to the service bulletin.
(d) Before further flight after doing paragraph (c) of this AD, do the actions required by paragraphs (d)(1) and (d)(2) of this AD.
(1) Remove the aft bulkhead fasteners of the lower spar fitting and do a one-time eddy current inspection of those fastener holes for cracking, according to Part V of the Accomplishment Instructions of Boeing Service Bulletin 757-54-0035, Revision 1, dated April 15, 1999; or Revision 2, dated June 13, 2002, excluding Evaluation Form.
(2) Do a detailed inspection of the 8 fasteners of the lower spar fitting for loose or missing fasteners, according to a method approved by the Manager, Seattle ACO. Before further flight, replace any loose or missing fasteners with new fasteners according to Boeing Service Bulletin 757-54-0035, Revision 1, dated April 15, 1999; or Revision 2, dated June 13, 2002, excluding Evaluation Form.
Note 4: The 8 fasteners are located in Panel 7 at Location 37. The number of fasteners at Location 37 has increased from 2 to 8 fasteners. Figure 30 of Boeing Service Bulletin 757-54-0035, Revision 2, dated June 13, 2002, excluding Evaluation Form, illustrates the location of the fasteners.
(e) If any cracking is found during any inspection required by this AD: Before further flight, repair according to a method approved by the Manager, Seattle ACO; or according to 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 repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.
(f) If no cracking is found during any inspection required by this AD, or after repair of cracking as required by paragraph (e) of this AD, before further flight, increase the diameter of the fastener holes and install new fasteners according to Boeing Service Bulletin 757-54-0035, Revision 2, dated June 13, 2002, excluding Evaluation Form.
(g) Except as identified in Figures 3 and 5 of the Accomplishment Instructions of Boeing Service Bulletin 757-54-0035, Revision 2, dated June 13, 2002, excluding Evaluation Form, the actions must be done using Boeing-supplied tools.
Alternative Methods of Compliance
(h)(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 Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.
(2) Alternative methods of compliance, approved previously in accordance with AD 99-24-07, amendment 39-11431, are approved as alternative methods of compliance with paragraph (a) of 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 Permit
(i) Special flight permits may be issued in accordance with 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.
Issued in Renton, Washington, on April 9, 2003. Ali Bahrami, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-9138 Filed 4-14-03; 8:45 am]
BILLING CODE 4910-13-P
