Airworthiness directives: Mitsubishi,

[Federal Register: May 18, 1999 (Volume 64, Number 95)]

[Rules and Regulations]

[Page 26831-26833]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr18my99-1]

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[[Page 26831]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-92-AD; Amendment 39-11169; AD 99-10-16]

RIN 2120-AA64

Airworthiness Directives; Mitsubishi Model YS-11 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to all Mitsubishi Model YS-11 series airplanes, that requires repetitive inspections to detect fatigue cracking in the manhole doublers of the lower wing panels; and repair, if necessary. This amendment also requires eventual modification of screw holes in the manhole doublers of the lower wing panels, which constitutes terminating action for the repetitive inspections required by this AD. This amendment is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent fatigue cracking in the manhole doublers of the lower wing panels, which could result in failure of the wing structure.

DATES: Effective June 22, 1999.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of June 22, 1999.

ADDRESSES: The service information referenced in this AD may be obtained from Mitsubishi Heavy Industries, Ltd., 10 Oye-cho, Minato-ku, Nagoya 455, Japan. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Jon Mowery, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5322; fax (562) 627-5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Mitsubishi Model YS-11 series airplanes was published in the Federal Register on July 9, 1998 (63 FR 37080). That action proposed to require repetitive inspections to detect fatigue cracking in the manhole doublers of the lower wing panels; and repair, if necessary. That action also proposed to require eventual modification of screw holes in the manhole doublers of the lower wing panels.

Comments

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

Request To Accept Modification as Terminating Action

Two commenters request that modification of the screw holes in the manhole doublers of the lower wing panels, as described in NAMC Service Bulletin 57-77, Revision 2, dated September 14, 1994, and specified in paragraph (b) of the proposed AD, be considered terminating action for the repetitive inspections described in paragraph (a) of the proposed rule. ``NOTE 2'' of the proposed AD states, ``Accomplishment of the modification specified in paragraph (b) does not constitute terminating action for the repetitive inspections of paragraph (a).'' The commenters state that repetitive inspections of the screw holes in the manhole doublers of the lower wing panels are no longer necessary after accomplishment of the modification, though inspection of the rivet holes in the skin around the manhole, as specified in SID Item 57-00- 03, is still necessary.

The FAA concurs with the commenters' request to accept the modification as terminating action for the repetitive inspections. The FAA has reviewed Mitsubishi NAMC Service Bulletin 57-77, Revision 2, and SID Item 57-00-03, and finds that repetitive inspections of the screw holes in the manhole doublers of the lower wing panels are no longer necessary after accomplishment of the modification specified in the service bulletin. Therefore, paragraph (b) of this final rule has been revised to eliminate reference to repair of any cracking detected during repetitive inspections performed after accomplishment of the modification, and to state that accomplishment of such modification terminates the repetitive inspection requirement of this AD. In addition, a reference to the modification as terminating action for the repetitive inspections has been added to the ``Summary'' section of this final rule. Also, ``NOTE 2'' of this final rule has been revised to state, ``Mitsubishi NAMC Supplemental Inspection Document (SID) Item 57-00-03 describes inspections of certain rivet holes in the skin around the manhole. Accomplishment of the modification specified in paragraph (b) of this AD does not eliminate the need for the inspections specified in that SID item.''

Request To Revise Address for Obtaining Service Information

One commenter requests that the proposed rule be revised to reference the correct address from which service information may be obtained. The commenter points out that Mitsubishi Heavy Industries, not Nihon Aeroplane Manufacturing Company (NAMC) (which was referenced as the appropriate source for the service information specified in the proposal), provides technical publications for owners and operators of Mitsubishi Model YS-11 series airplanes. The FAA concurs with the commenter's request and has revised this final rule to reference the correct address.

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Request To Revise Information From NAMC Structural Inspection Document

Two commenters request that the proposed AD be revised to more accurately reflect the information in NAMC Supplemental Inspection Document (SID) Item 57-00-03. The commenters point out that the following statement in the preamble of the proposed AD under the heading ``Differences Between Proposed Rule, Service Information, and Japanese Airworthiness Directive'' is incorrect: ``Following accomplishment of the modification described in the service bulletin, the SID item specifies that the repetitive interval is reduced to 6,000 flight cycles.'' One of the commenters attributes the misstatement in the proposed AD to a misunderstanding of a transmittal letter that accompanied the SID. That commenter states that the change in repetitive inspection interval referenced by the transmittal letter is for a different inspection item within the SID (Inspection Item 57-00- 06), and the repetitive interval for the inspection in SID Item 57-00- 03 remains at 8,000 flight cycles.

The FAA acknowledges that the proposed AD could have more accurately reflected the information in SID Item 57-00-03. However, the proposed AD is unaffected by the statement in the preamble. Because the section of the preamble that discusses the reduction of the repetitive interval is not repeated in the final rule, no change to the final rule is necessary in this regard.

Request To Revise Information From Japanese Airworthiness Directive

One commenter requests that the proposed rule be revised to reflect the correct compliance date for the modification as specified in Japanese Airworthiness Directive TCD-3795-2-96, dated December 13, 1996. Under the heading ``Differences Between Proposed Rule, Service Information, and Japanese Airworthiness Directive,'' the proposed rule states, `` * * * the Japanese airworthiness directive specifies that modification of the screw holes in the manhole doublers of the lower wing panels be accomplished prior to the accumulation of 60,000 total flight cycles, or before December 13, 2000 (four years after the effective date of the Japanese airworthiness directive), whichever occurs later.'' The commenter states that, due to a mistranslation in the English version of the AD, the date for required compliance is incorrect. The commenter goes on to state that the correct compliance date should be February 7, 1997, which is four years after the effective date of the original Japanese airworthiness directive (TCD- 3795-93, dated February 7, 1993). The FAA acknowledges that a mistranslation of the Japanese airworthiness directive occurred. However, the proposed AD is unaffected by the statement in the preamble. Because the subject section of the proposed rule is not restated in the final rule, no change to the final rule is necessary in this regard.

Request To Increase Repetitive Inspection Interval

One commenter requests that the repetitive inspection interval be increased from 6,000 flight cycles, as specified in paragraph (a) of the proposed AD, to 8,000 flight cycles. As described previously, the commenter points out that SID Item 57-00-03 recommends a repetitive inspection interval of 8,000 flight cycles.

The FAA does not concur with the commenter's request to increase the repetitive inspection interval from 6,000 to 8,000 flight cycles. In developing an appropriate compliance time for this AD, the FAA considered not only the repetitive inspection interval specified in SID Item 57-00-03, but also the degree of urgency associated with addressing the subject unsafe condition (fatigue cracking in the manhole doublers of the lower wing panels, which could result in failure of the wing structure). In light of these factors, as well as engineering judgement and experience, the FAA has determined that, due to the safety implications and consequences associated with the identified unsafe condition, a repetitive inspection interval that is more conservative than the 8,000-flight-cycle interval recommended by SID Item 57-00-03 is warranted. The FAA finds that an interval of 6,000 flight cycles will better ensure that any cracking of the manhole doublers of the lower wing panels is detected and corrected in a timely manner. No change to the final rule is necessary in this regard.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

The FAA estimates that 25 airplanes of U.S. registry will be affected by this AD.

It will take approximately 30 work hours per airplane to accomplish the required inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $45,000, or $1,800 per airplane, per inspection cycle.

It will take approximately 40 work hours per airplane to accomplish the required modification, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $60,000, or $2,400 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

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

[[Page 26833]]

Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

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

   Sec. 39.13 [Amended]

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

   99-10-16 Mitsubishi Heavy Industries, Ltd.: Amendment 39-11169. Docket 97-NM-92-AD.

   Applicability: All Model YS-11 series airplanes, 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 (c) 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 the manhole doublers of the lower wing panels, which could result in failure of the wing structure, accomplish the following:

   Initial and Repetitive Inspections

   (a) Perform a visual inspection to detect cracking in the manhole doublers and around the screw holes of the lower wing panels, in accordance with Mitsubishi Nihon Aeroplane Manufacturing Company (NAMC) Service Bulletin 57-77, Revision 2, dated September 14, 1994, at the time specified in either paragraph (a)(1) or (a)(2) of this AD, as applicable. Repeat the inspection thereafter at intervals not to exceed 6,000 flight cycles.

   (1) For airplanes that have accumulated fewer than 45,000 total flight cycles as of the effective date of this AD: Prior to the accumulation of 45,000 total flight cycles, or within 1 year after the effective date of this AD, whichever occurs later, perform the initial inspection.

   (2) For airplanes that have accumulated 45,000 or more total flight cycles as of the effective date of this AD: Within 2,000 flight cycles or 1 year after the effective date of this AD, whichever occurs first, perform the initial inspection.

   Modification

   (b) Modify the screw holes in the manhole doublers of the lower wing panels, in accordance with Mitsubishi NAMC Service Bulletin 57- 77, Revision 2, dated September 14, 1994, at the applicable time specified in either paragraph (b)(1) or (b)(2) of this AD. Accomplishment of such modification constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD.

   Note 2: Mitsubishi NAMC Supplemental Inspection Document (SID) Item 57-00-03 describes inspections of certain rivet holes in the skin around the manhole. Accomplishment of the modification specified in paragraph (b) of this AD does not eliminate the need for the inspections specified in that SID item.

   (1) If no cracking is found, prior to the accumulation of 60,000 total flight cycles, or within 1 year after the effective date of this AD, whichever occurs later, accomplish the modification in accordance with the service bulletin.

   (2) If any cracking is found, prior to further flight, repair the cracking and accomplish the modification, in accordance with the service bulletin.

   Alternative Methods of Compliance

   (c) 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, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO.

   Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.

   Special Flight Permits

   (d) 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.

   Incorporation by Reference

   (e) The inspection and modification shall be done in accordance with Mitsubishi Nihon Aeroplane Manufacturing Company (NAMC) Service Bulletin 57-77, Revision 2, dated September 14, 1994, which contains the following list of effective pages:

   Revision level shown Page number

   on page

   Date shown on page

   1-3.................. 2..................... September 14, 1994. 4-16.................. 1..................... November 4, 1993. 17, 18................ Original.............. January 8, 1993.

   This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Mitsubishi Heavy Industries, Ltd., 10 Oye-cho, Minato-ku, Nagoya 455, Japan. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

   Note 4: The subject of this AD is addressed in Japanese airworthiness directive TCD-3795-2-96, dated December 13, 1996.

   (f) This amendment becomes effective on June 22, 1999.

   Issued in Renton, Washington, on May 7, 1999. D. L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-12098Filed5-17-99; 8:45 am]

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