AD 99-27-04

This amendment adopts a new airworthiness directive (AD), applicable to certain Rolls-Royce Limited Dart series turboprop engines. This amendment requires a one-time visual inspection of the interior of the switch to determine the type of low torque switch, and removal from service of unapproved Klixon low torque switches and replacement with serviceable parts. This amendment is prompted by the discovery of unapproved low torque switches in fleet operation. The actions specified by this AD are intended to prevent possible low torque switch failure, which could result in failure of a propeller to auto-feather following an engine power loss, resulting in possible loss of control of the airplane due to high asymmetric drag.

Final rule; request for comments.

99-27-04 Rolls-Royce Limited: Amendment 39-11485. Docket 99-NE-30-AD. Issued December 21, 1999.
Applicability: Rolls-Royce Limited (R-R) Dart 506, 510, 511, 514, 525, 526, 529, 530, 531, 532, 535, 542, and 552 series turboprop engines, installed on but not limited to Gulfstream Aerospace Corp. G-159, British Aerospace HS 748, Fokker Aircraft F.27, Mitsubishi Heavy Industries YS-11, General Dynamics (Convair) 640 and 600 series, and Vickers Armstrongs (Aircraft Limited) Viscount.
Note 1: This airworthiness directive (AD) applies to each engine 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 engines 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 a propeller to auto-feather following an engine power loss, resulting in possible loss of control of the airplane due to high asymmetric drag, accomplish the following: Inspection
(a) Within 3 months after the effective date of this AD, accomplish the following in accordance with the Action section of R-R Service Bulletin (SB) No. Da61-13, dated December 1996:
(1) Remove the switch cover, visually inspect the interior of the switch and replace the switch cover, all in accordance with the accomplishment instructions of the SB.
(2) If a Klixon low torque switch, part number (P/N) 6PS-25-1, is installed, prior to further flight remove the Klixon low torque switch from service and replace with an approved low torque switch. 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, Engine Certification Office (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO. Ferry Flights
(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 required by this AD shall be done in accordancewith R-R SB No. Da61-13, dated December 1996. 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 Rolls-Royce Limited, Attn: Dart Engine Service Manager, East Kilbride, Glasgow G74 4PY, Scotland; telephone: +44 1355-220-200, fax: +44 1141-778-432. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.
(e) This amendment becomes effective on February 28, 2000.

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 Rolls-Royce Limited (R-R) Dart 506, 510, 511, 514, 525, 526, 529, 530, 531, 532, 535, 542, and 552 series turboprop engines was published in the Federal Register on August 26, 1999 (64 FR 46609). That action proposed to require a one-time visual inspection of the interior of the switch to determine the type of low torque switch within 3 months after the effective date of the AD, and removal from service of unapproved Klixon low torque switches and replacement with approved low torque switches. That action was prompted by AD 002-12-96, issued by the Civil Aviation Authority of the United Kingdom. That condition, if not corrected, could result in possible low torque switch failure, which could result in failure of a propeller to auto-feather following an engine power loss, resulting in possible loss of control ofthe airplane due to high asymmetric drag. No Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed. Economic Analysis
There are approximately 890 engines of the affected design in the worldwide fleet. The FAA estimates that 139 engines installed on aircraft of US registry will be affected by this AD, that it will take approximately 2 work hours per engine to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $12,500 per engine. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $1,754,180. 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 (EO) 13132.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under EO 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: