98-11436. Airworthiness Directives; Rolls-Royce, plc Viper Series Turbojet Engines

[Federal Register Volume 63, Number 83 (Thursday, April 30, 1998)]
[Proposed Rules]
[Pages 23688-23690]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-11436]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-06-AD]


Airworthiness Directives; Rolls-Royce, plc Viper Series Turbojet 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Rolls-Royce, plc Viper series 
turbojet engines. This proposal would require a one-time visual 
inspection of the barometric flow control unit (BFCU) augmentor and 
bypass valve joint washer for joint washer integrity, and replacement, 
if necessary, with serviceable parts. This proposal is prompted by a 
report of a high pressure fuel leak at the BFCU augmentor and bypass 
valve assembly joint, washer interface. The actions specified by the 
proposed AD are intended to prevent a high pressure fuel leak, which 
could result in an engine nacelle fire and damage to the aircraft.

DATES: Comments must be received by June 1, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 98-ANE-06-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, plc, Technical Publications Department CLS-
4, P.O. Box 3, Filton, Bristol, BS34 7QE England; telephone 117-979-
1234, 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].

[[Page 23689]]

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 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 98-ANE-06-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. 98-ANE-06-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), notified the Federal Aviation 
Administration (FAA) that an unsafe condition may exist on Rolls-Royce, 
plc (R-R) Viper Mk. 521, 522, 526 and 601 series turbojet engines. The 
CAA advises that they have received a report of an accident following 
an outbreak of fire on a military Viper variant due to a barometric 
flow control unit (BFCU) augmentor and bypass valve assembly interface 
joint failure. The failure is attributed to inadequate interface torque 
loads and manufacturing defects with the interface washer. The civil 
version of the Viper is sufficiently similar to the military variant 
that experienced the failure to warrant this AD action against the 
civil version. This condition, if not corrected, could result in a high 
pressure fuel leak, which could result in an engine nacelle fire and 
damage to the aircraft.
    R-R has issued Service Bulletins (SBs) Nos. 73-A120, 73-A121, 73-
A68, 73-A69, 73-A35, and 73-A36, dated November 1997, that specify 
procedures for a one-time inspection of BFCU augmentor and bypass valve 
joint washer for joint washer integrity, and replacement, if necessary, 
with serviceable parts. The CAA classified these SBs as mandatory 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.
    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 inspection 
of BFCU augmentor and bypass valve joint washer for joint washer 
integrity, and replacement, if necessary, with serviceable parts. The 
actions would be required to be accomplished in accordance with the SBs 
described previously.
    There are approximately 140 engines of the affected design in the 
worldwide fleet. The FAA estimates that 52 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, that 
it would take approximately 5 work hours per engine to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Based on these figures, the total cost impact of the proposed AD on 
U.S. operators is estimated to be $15,600.
    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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Rolls-Royce plc: Docket No. 98-ANE-06-AD.
    Applicability: Rolls-Royce plc (R-R) Viper Mk. 521, 522, 526 and 
601 series turbojet engines, installed on but not limited to 
Raytheon (formerly British Aerospace, Hawker Siddeley) Models BH.125 
and DH.125 series aircraft.

    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 (d) 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.

[[Page 23690]]

    To prevent a high pressure fuel leak, which could result in an 
engine nacelle fire and damage to the aircraft, accomplish the 
following:
    (a) For R-R Viper Mk. 521, and 522 series engines, perform a 
one-time inspection of the barometric flow control unit (BFCU) 
augmentor and bypass valve joint washer for joint washer integrity, 
and replace, if necessary, with serviceable parts, in accordance 
with R-R Service Bulletins (SBs) Nos. 73-A120 and 73-A121, as 
applicable, dated November 1997, as follows:
    (1) For engines with less than 200 hours time in service (TIS) 
since new, overhaul, or repair of the BFCU, inspect within 2 months, 
or 100 hours TIS after the effective date of this AD, whichever 
occurs first.
    (2) For engines with 200 or more hours TIS since new, overhaul, 
or repair of the BFCU, inspect at the next engine removal after the 
effective date of this AD.
    (b) For R-R Viper Mk. 526 series engines, perform a one-time 
inspection of the barometric flow control unit (BFCU) augment or and 
bypass valve joint washer for joint washer integrity, and replace, 
if necessary, with serviceable parts, in accordance with R-R Service 
Bulletins (SBs) Nos. 73-A68 and 73-A69, as applicable, dated 
November 1997, as follows:
    (1) For engines with less than 200 hours time in service (TIS) 
since new, overhaul, or repair of the BFCU, inspect within 2 months, 
or 100 hours TIS after the effective date of this AD, whichever 
occurs first.
    (2) For engines with 200 or more hours TIS since new, overhaul, 
or repair of the BFCU, inspect at the next engine removal after the 
effective date of this AD.
    (c) For R-R Viper Mk. 601 series engines, perform a one-time 
inspection of the BFCU augmentor and bypass valve joint washer for 
joint washer integrity, and replace, if necessary, with serviceable 
parts, in accordance with R-R SBs Nos. 73-A35 and 73-A36, as 
applicable, dated November 1997, as follows:
    (1) For engines with less than 200 hours TIS since new, 
overhaul, or repair of the BFCU, inspect within 2 months, or 100 
hours TIS after the effective date of this AD, whichever occurs 
first.
    (2) For engines with 200 or more hours TIS since new, overhaul, 
or repair of the BFCU, inspect at the next engine removal after the 
effective date of this AD.
    (d) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (e) 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 April 23, 1998.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 98-11436 Filed 4-29-98; 8:45 am]
BILLING CODE 4910-13-U