AD 98-21-05

This amendment adopts a new airworthiness directive (AD), applicable to all SD3-30, SD3-60, SD3-60 SHERPA, and SD3 SHERPA series airplanes, that requires repetitive visual inspections of the flap levers and bracket assembly of the inner flap sub-assembly of the left and right wings to detect certain discrepancies; and corrective actions, if necessary. This amendment is prompted by mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to detect and correct failure of the levers and bracket assembly, which could result in uncommanded retraction of the inner flap assembly and consequent reduced controllability of the airplane.

Final rule

98-21-05 SHORT BROTHERS PLC: Amendment 39-10813. Docket 98-NM-203-AD.
Applicability: All Model SD3-30, SD3-60, SD3-60 SHERPA, and SD3 SHERPA 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 (b) 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 failure of the levers and bracket assembly, which could result in uncommanded retraction of the inner flap assembly and consequent reduced controllability of the airplane, accomplish the following:

(a) Within 90 days after the effective date of this AD: Perform a visual inspection of the levers and bracket assembly of the inner flap sub-assembly of the left and right wings to detect discrepancies (i.e., corrosion, cracking, protective coating breakdown, and inadequate clearances between the forward face of the lower levers and the bracket web), in accordance with the applicable Shorts service bulletin specified below, all dated January 14, 1997:

_ SD360-27-26 (for Model SD3-60 series airplanes);
_ SD360 Sherpa 27-1 (for Model SD3-60 SHERPA series airplanes);
_ SD3 Sherpa 27-2 (for Model SD3 SHERPA series airplanes); and
_ SD3-27-36 (for Model SD3-30 series airplanes).

(1) If no discrepancy is detected, repeat the visual inspection thereafter at intervals not to exceed 4,800 flight hours or 24 months, whichever occurs earlier.

(2) If any discrepancy is detected, prior to further flight, rework the affected area, and accomplish follow-on corrective actions, in accordance with the applicable service bulletin.

(i) If the reworked parts remain within the allowable rework limits specified in the applicable service bulletin, repeat the visual inspection of the levers and bracket assembly thereafter at intervals not to exceed 1,200 flight hours or 6 months, whichever occurs earlier.

(ii) If any reworked part is outside the allowable rework limits specified in the applicable service bulletin, prior to further flight, replace the reworked part with a new part. Thereafter, repeat the inspection at intervals not to exceed 4,800 flight hours or 24 months, whichever occurs earlier.

(b) 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, International Branch, ANM-116, 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, International Branch, ANM-116.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(c) 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.

(d) The actions shall be done in accordance with the Shorts service bulletins specified below, as applicable:

_ SD360-27-26, dated January 14, 1997;
_ SD360 Sherpa 27-1, dated January 14, 1997;
_ SD3 Sherpa 27-2, dated January 14, 1997; and
_ SD3-27-36, dated January 14, 1997.

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 Short Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland. 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.

NOTE 3: The subject of this AD is addressed in British airworthiness directives 008-01-97, 010-01-97, 011-01-97, and 009-01-97.

(e) This amendment becomes effective on November 10, 1998.

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 SD3-30, SD3-60, SD3-60 SHERPA, and SD3 SHERPA series airplanes was published in the Federal Register on August 13, 1998 (63 FR 43333). That action proposed to require repetitive visual inspections of the flap levers and bracket assembly of the inner flap sub-assembly of the left and right wings to detect certain discrepancies; and corrective actions, if necessary.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
The FAA estimates that 99 airplanes of U.S. registry will be affected by this AD,that it will take approximately 5 work hours per airplane to accomplish the required inspection, and that the average labor rate is $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 $29,700, or $300 per airplane, per inspection cycle.

The 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.

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 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.

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