AD 99-18-11

This amendment adopts a new airworthiness directive (AD), applicable to all Short Brothers Model SD3-SHERPA, SD3-60 SHERPA, SD3-30, and SD3-60 series airplanes, that requires replacement of the existing bolts that secure the elevator control torque tube bearing housing retaining plate with hex head bolts. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent reduced movement of the elevator controls and consequent reduced controllability of the airplane, as a result of bolts coming loose on the elevator control torque tube bearing housing retaining plate.

Final rule

99-18-11 SHORT BROTHERS PLC: Amendment 39-11277. Docket 99-NM-12-AD. Issued August 23, 1999.
Applicability: All Model SD3-SHERPA, SD3-60 SHERPA, SD3-30, and SD3-60 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 reduced movement of the elevator controls and consequent reduced controllability of the airplane, as a result of bolts coming loose on the elevator control torque tube bearing housing retaining plate, accomplish the following:

Replacement
(a) Within 6 months after the effective date of this AD, replace the existing bolts of the elevator control torque tube bearing housing retaining plate with hex head bolts torqued to a value of 35 lb-ins, in accordance with Shorts Service Bulletins SD3 Sherpa-27-3, Revision 1, dated November 23, 1998 (for Model SD3-SHERPA series airplanes); SD3-60 Sherpa-27-3, Revision 1, dated November 23, 1998 (for Model SD3-60 SHERPA series airplanes); SD330-27-37, Revision 1, dated November 23, 1998 (for Model SD3-30 series airplanes); or SD360-27-28, Revision 1, dated November 23, 1998 (for Model SD3-60 series airplanes); as applicable.

Alternative Method of Compliance
(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.

Special Flight Permits
(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.

Incorporation by Reference
(d) The replacement shall be done in accordance with the following Shorts Service Bulletins, which contain the specified effective pages:Referenced and Date
Service Bulletin
Page Number
Revision Level
Shown on Page
Date Shown on Page
SD3 SHERPA-27-3,
Revision 1,
1 November 23, 1998
1

2-5
1

Original
November 23, 1998

November 16, 1998
SD3-60 SHERPA-27-3,
Revision, 1
November 23, 1998
1

2-5
1

Original
November 23, 1998

November 16, 1998
SD330-27-37,
Revision 1,
November 23, 1998
1

2-5
1

Original
November 23, 1998

November 16, 1998
SD360-27-28,
Revision 1,
November 23, 1998
1

2-5
1

Original
November 23, 1998

November 16, 1998

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 009-11-98, 010-11-98, 013-11-98, and 017-11-98.

(e) This amendment becomes effective on October 6, 1999.

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 Short Brothers Model SD3-SHERPA, SD3-60 SHERPA, SD3-30, and SD3-60 series airplanes was published in the Federal Register on June 28, 1999 (64 FR 34581). That action proposed to require replacement of the existing bolts that secure the elevator control torque tube bearing housing retaining plate with hex head bolts.

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 46 airplanes of U.S. registry will be affected by this AD, that it will take approximately 4 work hours perairplane to accomplish the required replacement, and that the average labor rate is $60 per work hour. Required parts will come from the operator's existing supply. Based on these figures, the cost impact of the required AD on U.S. operators is estimated to be $11,040, or $240 per airplane.

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: