AD 99-18-10

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 a one-time detailed visual inspection of the emergency brake accumulator mounting structure for evidence of cracking; and corrective action, if necessary. 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 failure of the mounting angle that supports the emergency brake system due to cracking, which could result in loss of the emergency brake system.

Final rule

99-18-10 SHORT BROTHERS PLC: Amendment 39-11276. Docket 98-NM-369-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 (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 failure of the mounting angle that supports the emergency brake system due to cracking, which could result in loss of the emergency brake system, accomplish the following: Inspection

(a) Within 3 months after the effective date of this AD, perform a detailed visual inspection of the emergency brake accumulator mounting angle for evidence of cracking in accordance with Shorts Service Bulletin SD3 SHERPA-29-2 (for Model SD3-SHERPA series airplanes); SD360 SHERPA-29-1 (for Model SD3-60 SHERPA series airplanes); SD330-29-19 (for Model SD3-30 series airplanes); or SD360-29-06 (for Model SD3-60 series airplanes); all dated October 22, 1998; as applicable. If any cracking is found, prior to further flight, remove and replace the mounting angle with a new or serviceable part in accordance with the applicable service bulletin.

NOTE 2: For the purposes of this AD, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required."

Reporting
(b) Within 10 days after accomplishing the inspection required by paragraph (a) of this AD, submit a report of the inspection results (both positive and negative findings) to Short Brothers PLC, Mel Smith, Team Leader Customer Support, facsimile number: 44-1232-733024. 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.

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, 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 3: 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
(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 replacement shall be done in accordance with Shorts Service Bulletin SD3 SHERPA-29-2, dated October 22, 1998; Shorts Service Bulletin SD360 SHERPA-29-1, dated October 22, 1998; Shorts Service Bulletin SD330-29-19, dated October 22, 1998; or Shorts Service Bulletin SD360-29-06, dated October 22, 1998; as applicable. 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 4: The subject of this AD is addressed in British airworthiness directives 009-10-98, 011-10-98, 008-10-98, and 010-10-98.

(f) This amendment becomes effective on October 5, 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 34575). That action proposed to require a one-time visual inspection of the emergency brake accumulator mounting structure for evidence of cracking; and corrective action, 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.

Explanation of Change Made to Proposal
The FAA has added a note to the final rule to clarify the definition of a detailed visual inspection.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Interim Action
This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Cost Impact
The FAA estimates that 56 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour 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 required AD on U.S. operators is estimated to be $3,360, or $60 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 providedunder 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: