AD 95-14-05 ACTIVE

95-14-05 MITSUBISHI HEAVY INDUSTRIES, LTD: Amendment 39-9297. Docket 94-NM- 167-AD.
Applicability: All Model YS-11 and -11A 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 use the authority provided in paragraph (h) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

NOTE 2: This AD references MHI Publication No. YS-MR-301, "YS-11 Corrosion Control Program," dated November 1, 1993 (hereafter referred to as "the Document"), for basic tasks, definitions of corrosion levels, compliance times, and reporting requirements. In addition, this AD specifies inspection and reporting requirements beyond those included in the Document. Where there are differences between the AD and the Document, the AD prevails.

NOTE 3: As used throughout this AD, the term "the FAA" is defined differently for different operators, as follows: For those operators complying with paragraph (a) of this AD, "the FAA" is defined as "the Manager of the Los Angeles Aircraft Certification Office (ACO)." For those operators operating under Federal Aviation Regulation (FAR) Part 121 or 129, and complying with paragraph (b) of this AD, "the FAA" is defined as "the cognizant Principal Maintenance Inspector (PMI)." For those operators operating under FAR Part 91 or 125, and complying with paragraph (b) of this AD, "the FAA" is defined as "the cognizant Maintenance Inspector at the appropriate FAA Flight Standards office."

To preclude degradation of the structural capabilities of the airplane due to the problems associated with corrosion, accomplish the following:

(a) Except as provided in paragraph (b) of this AD, within a date two years after the effective date of this AD, complete each of the basic tasks specified in Section 4.3 of the Document in accordance with the procedures specified in the Document and the schedule specified in Figure 5 of the Document. Thereafter, repeat each basic task at a time interval not to exceed the repeat interval specified in Section 4 of the Document for that task.

NOTE 4: A "basic task," as defined in Section 4 of the Document, includes inspections; procedures for a corrective action, including repairs, under identified circumstances; application of sealants or corrosion inhibitors; and other follow-on actions.

NOTE 5: Basic tasks completed in accordance with the Document before the effective date of this AD may be credited for compliance with the initial basic task requirements of this paragraph.

NOTE 6: Where non-destructive inspection (NDI) methods are employed, in accordance with Section 4 of the Document, the standards and procedures used must be acceptable to the Administrator in accordance with FAR Section 43.13.

(b) As an alternative to the requirements of paragraph (a) of this AD: Within one year after the effective date of this AD, revise the FAA-approved maintenance/inspection program to include the corrosion control program specified in the Document; or to include an equivalent program that is approved by the FAA.

(1) Any operator complying with paragraph (b) of this AD may use an alternativerecordkeeping method to that otherwise required by FAR Section 91.417 or Section 121.380 for the actions required by this AD, provided it is approved by the FAA and is included in a revision to the FAA-approved maintenance/inspection program.

(2) Subsequent to the accomplishment of the initial basic task, any extensions of repeat intervals specified in the Document must be approved by the FAA.

(c) To accommodate unanticipated scheduling requirements, it is acceptable for a repeat interval to be increased by up to 10%, but not to exceed 6 months. The FAA must be informed, in writing, of any such extension within 30 days after such adjustment of the schedule.

(d) (1) If, as a result of any inspection conducted in accordance with paragraphs (a) or (b) of this AD, Level 3 corrosion is determined to exist in any airplane area, accomplish either paragraph (d)(1)(i) or (d)(1)(ii) within 7 days after such determination:

(i) Submit a report of that determination to theFAA and complete the basic task in the affected aircraft zones on all Model YS-11/-11A series airplanes in the operator's fleet; or

(ii) Submit to the FAA for approval one of the following:

(A) A proposed schedule for performing the basic tasks in the affected aircraft zones on the remaining Model YS-11/-11A series airplanes in the operator's fleet, which is adequate to ensure that any other Level 3 corrosion is detected in a timely manner, along with substantiating data for that schedule; or

(B) Data substantiating that the Level 3 corrosion found is an isolated occurrence.

NOTE 7: Notwithstanding the provisions of Section 1.3 of the Document, which would permit corrosion that otherwise meets the definition of Level 3 corrosion (i.e., which is determined to be a potentially urgent airworthiness concern requiring expeditious action) to be treated as Level 1 if the operator finds that it "can be attributed to an event not typical of the operator's usage of other airplanes in the same fleet," this paragraph requires that data substantiating any such finding be submitted to the FAA for approval.

(2) The FAA may impose schedules other than those proposed, upon finding that such changes are necessary to ensure that any other Level 3 corrosion is detected in a timely manner.

(3) Within the time schedule approved under paragraph (d)(1) or (d)(2) of this AD, accomplish the basic tasks in the affected aircraft zones of the remaining Model YS-11/-11A series airplanes in the operator's fleet.

(e) If, as a result of any inspection after the initial inspection conducted in accordance with paragraph (a) or (b) of this AD, it is determined that corrosion findings exceed Level 1 in any area, within 60 days after such determination, implement a means, approved by the FAA, to reduce future findings of corrosion in that area to Level 1 or better.

(f) Before any operator places into service any airplane subject to the requirements of this AD, a schedule for the accomplishment of basic tasks required by this AD must be established in accordance with paragraph (f)(1) or (f)(2) of this AD, as applicable:

(1) For airplanes previously maintained in accordance with this AD, the first basic task in each aircraft zone to be performed by the new operator must be accomplished in accordance with the previous operator's schedule or with the new operator's schedule, whichever would result in the earlier accomplishment date for that task. After each basic task has been performed once, each subsequent task must be performed in accordance with the new operator's schedule.

(2) For airplanes that have not been previously maintained in accordance with this AD, the first basic task for each aircraft zone to be performed by the new operator must be accomplished prior to further flight or in accordance with a schedule approved by the FAA.

(g) Reports of Level 2 and Level 3 corrosion must be submitted at least every three months to Mitsubishi Heavy Industries, Ltd., in accordance with Section 3 of the Document.

NOTE 8: Reporting of Level 2 and Level 3 corrosion found as a result of any opportunity inspections is highly desirable.

(h) 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 9: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.

(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.

(j) Reports of inspection results required by this AD 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.

(k) The actions shall be done in accordance with MHI Publication No. YS-MR-301, "YS-11 Corrosion Control Program," dated November 1, 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 Nihon Aeroplane Manufacturing, Toranomon Daiichi, Kotohire-Cho, Shiba, Minato-Ku, Tokyo, Japan. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, Transport Airplane Directorate, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(l) This amendment becomes effective on August 7, 1995.

FOR FURTHER INFORMATION CONTACT: William Roberts, Aerospace Engineer, Airframe Branch, ANM-120L, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (310) 627-5228; fax (310) 627-5210.