AD 94-06-02 ACTIVE

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Short Brothers PLC Model SD3-30, SD3-60, and SD3-SHERPA series airplanes, that currently requires an inspection to detect corrosion on the distance piece associated with the wing strut pick up on the stub wing, and repair of corroded parts. This amendment requires repetitive inspections to detect corrosion of repaired or reworked distance pieces and adjacent side plates; and provides a terminating action for the repetitive inspections. This amendment is prompted by reports of corrosion on the distance pieces and adjacent side plates of the wing strut pick up. The actions specified by this AD are intended to prevent failure of the distance piece and adjacent side plates, which could result in reduced strength of the wing strut attachment to the stub wing on the fuselage and, subsequently, reduced structural strength of the main wing.

Final rule

94-06-02 SHORT BROTHERS PLC: Amendment 39-8850. Docket 93-NM-141-AD. Supersedes AD 93-09-08, Amendment 39-8574.
Applicability: Model SD3-SHERPA series airplanes, serial numbers SH3201 through SH3216 inclusive; all Model SD3-60 series airplanes; and all Model SD3-30 series airplanes; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the distance piece and adjacent side plates, which could result in reduced strength of the wing strut attachment to the stub wing on the fuselage and, subsequently, reduced structural strength of the main wing, accomplish the following:

(a) Within 30 days after May 27, 1993 (the effective date of AD 93-09-08, Amendment 39-8574), perform a detailed visual inspection to detect corrosion in the pockets on the horizontal leg of the distance piece associated with the wing strut pick up on the left- and right-stub wings, in accordance with Shorts Service Bulletin SD3 SHERPA-53-1, dated March 29, 1993, or Revision 1, dated May 1993 (for Model SD3-SHERPA series airplanes); Shorts Service Bulletin SD360-53-38, dated March 25, 1993, or Revision 1, dated May 1993 (for Model SD3-60 series airplanes); or Shorts Service Bulletin SD330-53-65, dated March 29, 1993, or Revision 1, dated May 1993 (for Model SD3-30 series airplanes); as applicable.

(1) If any corrosion is detected that is within the limits specified in the applicable service bulletin, prior to further flight, repair or rework the corroded components in accordance with the applicable service bulletin.

(2) If any corrosion is detected that is outside the limits specified in the applicable service bulletin, prior to further flight, accomplish either paragraph (a)(2)(i) or (a)(2)(ii) of this AD:

(i) Replace any corroded distance piece with a new, improved distance piece (without pockets), and repair or replace the adjacent side plates, as necessary, in accordance with the applicableservice bulletin. Or

(ii) Repair or rework the corroded components in accordance with a method approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.

(3) If no corrosion is detected, accomplish the requirements of paragraph (b) of this AD.

(b) Within 10 days after accomplishing the initial inspection required by paragraph (a)(1) of this AD, submit a report of all inspection findings, including nil defects, to Short Brothers PLC. 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.

(c) For those airplanes on which the distance piece has been reworked or repaired in accordance with the requirements of paragraph (a) of this AD: Within 90 days after the effective date of this AD or within the next 600 hours time-in-service after the effective date of this AD, whichever occurs earlier, and thereafter at intervals not to exceed 90 days or 600 hours time-in- service, whichever occurs earlier, repeat the inspection of the distance piece and adjacent side plates in accordance with the requirements of paragraph (a) of this AD.

(d) Replacement of the existing distance piece and/or adjacent side plates with new distance pieces (without pockets) and/or adjacent side plates in accordance with Short Brothers Service Bulletins SD3 SHERPA-53-2, dated July 1993 (for Model SD3-SHERPA series airplanes); SD360-53-39, dated June 11, 1993 (for Model SD3-60 series airplanes); or SD330-53-66, dated July 1993 (for Model SD3-30 series airplanes); as applicable; constitutes terminating action for the repetitive inspection requirement of paragraph (c) of this AD.

(e) 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, Standardization Branch, ANM-113, 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, Standardization Branch, ANM-113.

NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(f) Special flight permits may be issued in accordance with Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.

(g) The actions shall be done in accordance with Shorts Service Bulletin SD3 SHERPA- 53-1, Revision 1, dated May 1993; Shorts Service Bulletin SD360-53-38, Revision 1, dated May 1993; Shorts Service Bulletin SD330-53-65, Revision 1, dated May 1993; Shorts Service Bulletin SD3 SHERPA-53-2, dated July 1993; Shorts Service Bulletin SD360-53-39, dated June 11, 1993, or Shorts Service Bulletin SD330-53-66, dated July 1993, as applicable. The following Shorts service bulletins contain the specified effective pages:

Service Bulletin
Referenced and Date

Page Number

Revision Level
Shown on Page

Date
Shown on Page
SD3 SHERPA-53-1,
Revision 1,
May 1993
1, 3-7

2
1

Original
May 1993

March 1993
SD360-53-38,
Revision 1,
May 1993
1, 3-7

2
1

Original
May 1993

March 1993

This incorporation by reference is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Certain other actions shall be done in accordance with Shorts Service Bulletin SD3 SHERPA-53-1, dated March 29, 1993; Shorts Service Bulletin SD360- 53-38, dated March 25, 1993; and Shorts Service Bulletin SD330-53-65, dated March 29, 1993. The incorporation by reference of these documents was approved previously by the Director of the Federal Register in accordance with 5 U.S.C.552(a) and 1 CFR Part 51 as of May 27, 1993 (58 FR 27928, May 12, 1993). Copies may be obtained from Short Brothers PLC, 2011 Crystal Drive, Suite 713, Arlington, Virginia 22202-3719. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(h) This amendment becomes effective on May 16, 1994.

FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2148; fax (206) 227-1320.

A proposal to amend part 39 of the Federal Aviation Regulations by superseding AD 93-09-08, Amendment 39-8574 (58 FR 27928, May 12, 1993), which is applicable to certain Short Brothers PLC Model SD3-30, SD3-60, and SD3-SHERPA series airplanes, was published in the Federal Register on November 5, 1993 (58 FR 58992). The action proposed to supersede AD 93-09-08 to continue to require a one-time inspection to detect corrosion on the distance piece associated with the wing strut pick up on the stub wing, and repair or rework of corroded parts. The AD also proposed to require repetitive inspections to detect corrosion of repaired or reworked original equipment type distance pieces (with pockets) and adjacent side plates.

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

The commenter supports the proposed rule.

After careful reviewof the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that 106 airplanes of U.S. registry will be affected by this AD. The currently required one-time inspection action requires approximately 5 work hours per airplane to accomplish the actions, at an average labor rate is $55 per work hour. Based on these figures, the total cost impact of that action on U.S. operators is estimated to be $29,150, or $275 per airplane.

For operators who replace or repair a distance piece, this AD will require that repetitive inspections of that distance piece be performed. Such inspections will require approximately 5 work hours to accomplish, at an average labor charge of $55 per work hour. Based on these figures, the total cost impact of the repetitive inspections that will be required of these operators will be $275 per airplane per inspection cycle.

Shouldan operator elect to accomplish the optional terminating action that will be provided by this AD action, the number of hours required to accomplish it will be approximately 80 per airplane, at an average labor charge of $55 per work hour. The cost of required parts will be approximately $2,600 per airplane. Based on these figures, the total cost impact of the optional terminating action on U.S. operators will be $7,000 per airplane.

The total cost impact figure discussed above is 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.

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

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

39.13 - [Amended]
2. Section 39.13 is amended by removing amendment 39-8574 (58 FR 27928, May 12, 1993), and by adding a new airworthiness directive (AD), amendment 39-8850, to read as follows:

The service information referenced in this AD may be obtained from Short Brothers PLC, 2011 Crystal Drive, Suite 713, Arlington, Virginia 22202-3719. 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 Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

William Schroeder, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2148; fax (206) 227-1320.