[Federal Register Volume 60, Number 190 (Monday, October 2, 1995)]
[Proposed Rules]
[Pages 51376-51378]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-24438]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-43]


Airworthiness Directives; Rolls-Royce plc Dart Series Turboprop 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to Rolls-Royce plc (R-R) Dart 
series turboprop engines, that currently establishes a life limit for 
propeller low torque switches. This action 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 proposal is 
prompted by the need to add omitted part numbers and engine models to 
the AD. The actions specified by the proposed 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.

DATES: Comments must be received by December 1, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-43, 12 New England 
Executive Park, Burlington, MA 01803-5299. 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 plc, Attn: Dart Engine Service Manager, East 
Kilbride, Glasgow G74 4PY, Scotland. This information may be examined 
at the FAA, New England Region, Office of the Assistant Chief Counsel, 
12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone (617) 238-
7134, fax (617) 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 

[[Page 51377]]
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 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 94-ANE-43.'' 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 Assistant Chief Counsel, 
Attention: Rules Docket No. 94-ANE-43, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    On January 4, 1990, the Federal Aviation Administration (FAA) 
issued airworthiness directive (AD) 90-08-12, Amendment 39-6473 (55 FR 
12477, April 4, 1990), to establish a life limit for propeller low 
torque switches on Rolls-Royce plc (R-R) Dart series turboprop engines. 
That action was prompted by the FAA's determination that propeller low 
torque switch snap diaphragms had continued to crack in service despite 
the inspection and overhaul requirements of a previous AD, 77-20-04 R1. 
That condition, if not corrected, could result in cracking of the snap 
diaphragm in the propeller low torque switch, which could delay 
propeller auto-feathering and thereby adversely affect aircraft 
controllability.
    Since the issuance of AD 90-08-12, the FAA has determined that two 
propeller low torque switch part numbers, L944772 and L944774, and two 
R-R Dart engine models, Mk. 551 and 552, were omitted from that AD.
    This engine model is manufactured in the United Kingdom 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 Civil Aviation Authority (CAA), 
which is the airworthiness authority for the United Kingdom, 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 of operation in the United States.
    Rolls-Royce plc has issued R-R Dart Aero Engine Service Bulletin 
(SB) No. Da61-12, Revision 2, dated September 1978, that describes 
procedures for removal from service of propeller low torque switches.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would supersede AD 90-08-12 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.
    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 would be affected by this proposed AD, that 
it would take approximately 1.5 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 $3,800 per engine. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $1,750,500.
    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 USC 106(g), 40101, 40113, 44701.


Sec. 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 to 
read as follows:

Rolls-Royce plc: Docket No. 94-ANE-43. Supersedes AD 90-08-12, 
Amendment 39-6473.

    Applicability: Rolls-Royce plc (R-R) Dart Mk. 506, 510, 511, 
514, 515, 520, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, 
535, 536, 542, 543, 551, and 552 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) 600, and Vickers 
Armstrongs (Aircraft) Limited Viscount.

    Note: 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 use the 
authority provided in paragraph (e) to request approval from the 
Federal Aviation Administration (FAA). This approval may address 
either no action, if the current configuration eliminates the unsafe 
condition, or different actions necessary to address the unsafe 
condition described in this AD. Such a request should include an 
assessment of the effect of the changed configuration on the unsafe 
condition addressed by this AD. In no case does the presence of any 
modification, alteration, or repair remove any engine from the 
applicability of this AD.

    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 412, L944707 

[[Page 51378]]
through 709, L944738 through 740, L944742 through 744, 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) 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. The 
request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (f) 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.

    Issued in Burlington, Massachusetts, on September 21, 1995.
James. C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-24438 Filed 9-29-95; 8:45 am]
BILLING CODE 4910-13-U