Airworthiness directives: Royce Ltd.,

[Federal Register: August 26, 1999 (Volume 64, Number 165)]

[Proposed Rules]

[Page 46609-46611]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr26au99-13]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-30-AD]

RIN 2120-AA64

Airworthiness Directives; Rolls-Royce Limited Dart Series Turboprop Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Rolls-Royce Limited Dart series turboprop engines. This proposal would require 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 proposal is prompted by the discovery of unapproved low torque switches in fleet operation. The actions specified by the proposed 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.

DATES: Comments must be received by September 27, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-30-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be submitted to the Rules Docket by using the following Internet address: ``9-ane-adcomment@faa.gov''. Comments may be inspected at this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule 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. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: James Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7176, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by

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interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99-NE-30-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-30-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the Federal Aviation Administration (FAA) that an unsafe condition may exist on Rolls-Royce Limited (R-R) Dart 506, 510, 511, 514, 525, 526, 529, 530, 531, 532, 535, 542, and 552 series turboprop engines. The CAA advises that in 1976, failure of a low torque switch resulted in a fatal military airplane accident. The investigation revealed problems with the low torque switch that were resolved in a subsequent airworthiness action.

Recently, however, the CAA has determined that a number of unapproved, Klixon low torque switches, part number (P/N) 6PS-25-1, are in service. These low torque switches have not been tested by R-R and are not approved for use by R-R or the CAA on R-R Dart series turboprop engines, and are of a different design than the approved, capsule and snap diaphragm assembly low torque switches. All low torque switches sense reduction gearbox torque pressure, which is related to engine power output, and is set to trigger at a predetermined pressure. While there have been no failures to date of the unapproved Klixon low torque switches, the CAA and R-R cannot determine whether the switch will function properly. The low torque switch remains dormant until an emergency situation, and there are no functional preflight checks of the low torque switch system to ensure safe operation. This condition, if not corrected, 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.

Service Information

R-R has issued Service Bulletin (SB) No. Da61-13, dated December 1996, that specifies procedures for performing a 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. Externally, the Klixon low torque switches are indistinguishable from the approved low torque switches. The CAA classified this SB as mandatory and issued AD 002-12-96 in order to assure the airworthiness of these engines in the UK.

This engine model is manufactured in the UK and is type certificated for operation in the United States under the provisions of Section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design registered in the United States, the proposed AD would require 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 approved low torque switches. This action would be required within 3 months after the effective date of this AD. The actions would be required to be accomplished in accordance with the SB described previously.

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 would be affected by this proposed AD, that it would take approximately 2 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Required parts would cost approximately $12,500 per engine. Based on these figures, the total cost impact of the proposed AD on US operators is estimated to be $1,754,180.

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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:

   Rolls-Royce Limited: Docket No. 99-NE-30-AD.

   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

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   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:

   (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.

   (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.

   (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.

   Issued in Burlington, Massachusetts, on August 19, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 99-22194Filed8-25-99; 8:45 am]

   BILLING CODE 4910-13-U