AD 2001-24-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Short Brothers Model SD3 series airplanes, that requires repetitive tests (checks) of the engine power lever to ensure that the fuel control unit (FCU) lever is contacting the maximum stop, adjustment of the FCU rigging, if necessary, and an engine ground run for correct gas generator rotational speed. This AD also requires a static reduced power check on each engine to ensure correct operation of the reserve takeoff power (RTOP) system; and follow-on actions, if necessary. This action is necessary to prevent failure of the engines to reach adequate RTOP boost during takeoff, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2001-24-09 Short Brothers PLC: Amendment 39-12525. Docket 2001-NM-113-AD.

Applicability: All Model SD3-SHERPA, SD3-60, and SD3-60 SHERPA series airplanes; and Model SD3-30 series airplanes having PT6A-45R series engines; 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 engines to reach adequate reserve takeoff power (RTOP) boost during takeoff, which could result in reduced controllability of the airplane, accomplish the following:

Repetitive Inspections/Corrective Action

(a) Within 100 flight cycles or 90 days after the effective date of this AD, whichever comes later: Do a test (check) of the engine power lever to ensure that the fuel control unit (FCU) lever is contacting the maximum stop, and adjust the FCU rigging if the lever is not contacting the stop; do an engine ground run for correct gas generator rotational speed; and do a static reduced power check on each engine to ensure correct operation of the RTOP system; per Shorts Service Bulletin SD3 SHERPA-71-2, SD360 SHERPA-71-2, SD360-71-19, or SD330-71-24; all Revision 1; all dated August 2, 2001; as applicable. Before further flight, do any follow-on actions necessary (includes a functional check of the RTOP solenoid, replacement of any defective RTOP solenoid with a new solenoid, adjustment of the RTOP system if system fails to provide adequate boost, adjustment to the torque of the FCU Ng servo valve, test for leakage or restrictions of the FCU pnuematic system, or overhaul of the FCU), per the applicable service bulletin. Repeat the tests (checks) after that at intervals not to exceed 90 days.

Note 2: Tests, checks, and follow-on actions accomplished before the effective date of this AD per Shorts Service Bulletin SD3 SHERPA-71-2, SD360 SHERPA-71-2, SD360-71-19, or SD330-71-24; all dated February 5, 2001; as applicable; are acceptable for compliance with paragraph (a) of this AD.

Alternative Methods 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, Transport Airplane Directorate, FAA. 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

(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 actions shall be done in accordance with Shorts Service Bulletin SD3 SHERPA-71-2, Revision 1, dated August 2, 2001; Shorts Service Bulletin SD360 SHERPA-71-2, Revision 1, dated August 2, 2001; Shorts Service Bulletin SD360-71-19, Revision 1, dated August 2, 2001; or Shorts Service Bulletin SD330-71-24, Revision 1, dated August 2, 2001; 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 002-02-2001, 003-02-2001, 004-02-2001, and 005-02-2001.

Effective Date

(e) This amendment becomes effective on January 7, 2002.

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 certain Short Brothers Model SD3 series airplanes was published in the Federal Register on August 28, 2001 (66 FR 45196). That action proposed to require repetitive tests (checks) of the power lever movement of the fuel control unit (FCU) lever to ensure the lever is contacting the maximum stop, adjustment of the FCU rigging, if necessary, and an engine ground run for correct gas generator rotational speed. That action also proposed to require a static reduced power check on each engine to ensure correct operation of the reserve takeoff power system; and follow-on actions, if necessary.

Comments

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.

Remove Repetitive Tests/Checks

The commenter requests that the FAA revise the proposed AD to remove the requirement for repetitive tests (checks) every 90 days. The commenter suggests that, after the initial tests, the tests should only be repeated after the FCU is replaced or during a "Hot Section" inspection.

We do not concur with the commenter's request. The commenter provides no justification for its request and no data to support that its suggestion would provide an acceptable level of safety. No change to the final rule is necessary in this regard.

Explanation of New Relevant Service Information

Since the issuance of the proposed AD, the manufacturer has issued Shorts Service Bulletins SD3 SHERPA-71-2, SD360 SHERPA-71-2, SD360-71-19, and SD330-71-24; all Revision 1; all dated August 2, 2001. The proposed rule referenced the original issues of these service bulletins, all dated February 5, 2001, as the appropriate sources of service information for accomplishment of the proposed actions. The actions in Revision 1 are essentially similar to those in the original issue of the service bulletins. Revision 1 of all four service bulletins corrects minor errors and clarifies certain procedures for the static reduced power check on each engine. Accordingly, the FAA has revised paragraph (a) of this final rule to refer to Revision 1 of the service bulletins as the appropriate sources of service information for the actions required by that paragraph. Also, the FAA has added a new Note 2 to this final rule (and re-lettered subsequent notes accordingly) to give credit for tests, checks, and follow-on actions accomplished before the effective date of this AD per the original issue of the applicable service bulletin.

Explanation of Changes to Terminology

For clarification, the FAA has revised the "Summary" section and paragraph (a) of the proposed AD to clarify certain terminology concerning the test of the engine power lever to ensure that the lever is contacting the maximum stop.

Conclusion

After careful review of the available data, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

The FAA estimates that 46 Model SD3 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required tests (checks), and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $8,280, or $180 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. The cost impact figures discussed in ADrulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

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, positiveor 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.

Sec. 39.13 [Amended]

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