99-22194. Airworthiness Directives; Rolls-Royce Limited Dart Series Turboprop Engines

[Federal Register Volume 64, Number 165 (Thursday, August 26, 1999)]
[Proposed Rules]
[Pages 46609-46611]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22194]


=======================================================================
-----------------------------------------------------------------------

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: 
[e-mail]''. 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: [phone], 
fax: [phone]. 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 [phone].

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

[[Page 46610]]

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

[[Page 46611]]

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. 99-22194 Filed 8-25-99; 8:45 am]
BILLING CODE 4910-13-U