AD 98-04-13

This amendment supersedes an existing airworthiness directive (AD), applicable to Rolls-Royce Limited (R-R) Dart series turboprop engines, that currently establishes a life limit for propeller low torque switches. This amendment adds two propeller low torque switch part numbers and two R-R Dart engine models that were omitted from the current AD, and establishes a calendar end-date for removal of propeller low torque switches from service. This amendment is prompted by the need to add omitted part numbers and engine models to the AD. The actions specified by this AD are intended to prevent cracking of the snap diaphragm in the propeller low torque switch, which could delay propeller auto-feathering and thereby adversely affect aircraft controllability.
The incorporation by reference of certain publications listed in the regulations is approved
by the Director of the Federal Register as of March 24, 1998.

Final rule.

98-04-13 Rolls-Royce Limited: Amendment 39-10325. Docket 94-ANE-43. Supersedes AD 90-08-12, Amendment 39-6473.
Applicability: Rolls-Royce Limited (R-R) Dart Mk. 506, 510, 511 series, 514 series, 525 series, 526, 527, 528 series, 529 series, 530, 531, 532 series, 535 series, 542 series, 551 series, and 552 series turboprop engines, installed on but not limited to the following aircraft: Gulfstream Aerospace Corp. G-159, British Aerospace HS 748, Fokker Aircraft F.27, Mitsubishi Heavy Industries YS-11, General Dynamics (Convair) 580 and 600 series, and Vickers Armstrongs (Aircraft Limited) Viscount.
Note 1: Rolls-Royce Limited engine models Mk. 515, 520, 533, 534, 536, and 543 were removed in this final rule from the NPRM as these engine models were not U.S.-validated.
Note 2: Other changes to the final rule's applicability from the NPRM's applicability are as follows: Mk. 511 was changed to Mk. 511 series Mk. 514 was changed to Mk. 514 series Mk. 525 was changed to Mk.525 series Mk. 528 was changed to Mk. 528 series Mk. 529 was changed to Mk. 529 series Mk. 532 was changed to Mk. 532 series Mk. 535 was changed to Mk. 535 series Mk. 542 was changed to Mk. 542 series Mk. 551 was changed to Mk. 551 series Mk. 552 was changed to Mk. 552 series.
Note 3: 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 (f) 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 cracking of the snap diaphragm in the propeller low torque switch, which could delay propeller auto-feathering and thereby adversely affect aircraft controllability, remove from service propeller low torque switch part numbers (P/N) 3700892, 3700895, 3701232, 3500355, 3500356, 3500410 through 3500412, L944707 through L944709, L944738 through L944740, L944742 through L944744, L944769, L944772, and L944774, in accordance with R-R Dart Aero Engines Service Bulletin (SB) No. Da61-12, Revision 2, dated September 1978, as follows:
(a) Remove from service propeller low torque switches that have accumulated 5 or more calendar years time in service (TIS) on the effective date of this AD, within 30 days after the effective date of this AD, and replace with a serviceable part.
(b) Remove from service propeller low torque switches that have accumulated less than 5 calendar years TIS on the effective date of this AD, within 5 calendar years total TIS, or within 30 days after the effective date of this AD, whichever occurs later, and replace with a serviceable part.
(c) Remove from service propeller low torque switches that cannot have their in-service calendar time established within 30 days after the effective date of this AD, and replace with a serviceable part.
(d) Thereafter, remove from service new or overhauled propeller low torque switches at or prior to accumulating 5 calendar years TIS since initial installation on an engine. This limit includes storage or on-shelf time accumulated after initial installation on an engine. Overhaul of the propeller low torque switch zero-times the part.
(e) For the purpose of this AD, a serviceable part is defined as a new or overhauled propeller low torque switch with less than 5 calendar years TIS since first entry into service.
(f) 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. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
Note 4: Information concerning the existence of approved alternative method of compliance with this AD, if any, may be obtained from the Engine Certification Office.
(g) 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 aircraft to a location where the requirements of this AD can be accomplished.
(h) The actions required by this AD shall be done in accordance with the following R-R SB:

Document No.
Pages
Revision
Date
Dart Aero Engines SB

No. Da61-12
1-4
2
September 1978

5-6
Original
May 1976
Total pages: 6.

This incorporationby 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 plc, Attn.: Dart Engine Service Manager, East Kilbride, Glasgow G74 4PY, Scotland. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief 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.
(i) This amendment becomes effective on March 24, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding Airworthiness Directive (AD) 90-08-12, Amendment 39-6473 (55 FR 12477, April 4, 1990), which is applicable to Rolls-Royce Limited (R-R) Dart series turboprop engines, was published in the Federal Register on October 2, 1995 (60 FR 51377). That action proposed to add two propeller low torque switch part numbers and two R-R Dart engine models that were omitted from AD 90-08-12. In addition, the proposed AD establishes 30 days after the effective date of the AD as a calendar end-date for removal of propeller low torque switches.
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 manufacturer has confirmed that since the issuance of the NPRM, all affected engines have had the low torque switch removed. Therefore,there are no affected engines installed on aircraft of U.S. registry and further opportunity for comment is unnecessary.
The FAA has made some changes to the applicability paragraph of this AD to reflect the lack of affected engines installed on aircraft of U.S. registry and changes from Mk. to Mk. series.
There are approximately 2,880 engines of the affected design in the worldwide fleet. The FAA estimates that 450 engines installed on aircraft of U.S. registry will be affected by this AD, that it will take approximately 1.5 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 $3,800 per engine. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $1,750,500.
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 ofpower 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 removing Amendment 39-6473 (55 FR 12477, April 4, 1990) and by adding a new airworthiness directive, Amendment 39-10325, to read as follows: