[Federal Register Volume 68, Number 46 (Monday, March 10, 2003)]
[Proposed Rules]
[Pages 11342-11345]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-5577]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-ANE-08-AD]
RIN 2120-AA64


Airworthiness Directives; Turbomeca Arriel 1 Series Turboshaft 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration (FAA) proposes to 
supersede an existing airworthiness directive (AD), applicable to 
Turbomeca Arriel 1 A, 1 A1, 1 A2, 1 B, 1 C, 1 C1, 1 C2, 1 D, and 1 D1 
turboshaft engines. That AD currently requires repetitive checks for 
engine rubbing noise during gas generator rundown following engine 
shutdown, and for free rotation of the gas generator by rotating the 
compressor manually after the last flight of the day. In addition, the 
AD 95-11-01 requires installation of modification TU 202 or TU 197 as 
terminating action to the repetitive checks. This proposal would add 
additional engine models to the applicability section, would eliminate 
the installation of modification TU 197 as a terminating action to the 
repetitive checks, would require additional inspections for engines 
that have modification TU 197 installed, and would require the 
replacement of modifications TU 76 and TU 197 with modification TU 202, 
as a terminating action to the repetitive checks and inspections. This 
proposal is prompted by a report of an in-flight engine shutdown on an 
engine that had modification TU 197 installed, and the need to update 
the modification standard on certain engine models. The actions 
specified by the proposed AD are intended to prevent engine failure due 
to rubbing of the 2nd stage turbine disk on the 2nd stage turbine 
nozzle guide vanes, which could result in complete engine failure and 
damage to the helicopter.

DATES: Comments must be received by May 9, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 94-ANE-08-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. Comments may also be sent via 
the Internet using the following address: [email protected]. 
Comments sent via the Internet must contain the docket number in the 
subject line.
    The service information referenced in the proposed rule may be 
obtained from 40220 Tarnos, France; telephone (33) 05 59 64 40 00, fax 
(33) 05 59 64 60 80. This information may be examined, by appointment, 
at the FAA, New England Region, Office of the Regional Counsel, 12 New 
England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Antonio Cancelliere, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (781) 238-7751; 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 action 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 action must submit a self-addressed, 
stamped

[[Page 11343]]

postcard on which the following statement is made: ``Comments to Docket 
Number 94-ANE-08-AD.'' The postcard will be date stamped and returned 
to the commenter.

Availability of NPRM's

    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. 94-ANE-08-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    On May 15, 1995, the FAA issued airworthiness directive (AD) 95-11-
01, Amendment 39-9235 (60 FR 27023, May 22, 1995), applicable to 
Turbomeca Arriel 1 series turboshaft engines, to require repetitive 
checks for engine rubbing noise during gas generator rundown following 
engine shutdown, and for free rotation of the gas generator by rotating 
the compressor manually at a daily interval until installation of 
improved 2nd stage turbine nozzle guide vanes. That action was prompted 
by comments submitted by operators of the affected engines in response 
to a previous AD and the availability of improved design 2nd stage 
turbine nozzle guide vanes. That condition, if not corrected, could 
result in engine failure due to rubbing of the 2nd stage turbine disk 
on the 2nd stage turbine nozzle guide vanes, which could result in 
complete engine failure and damage to the helicopter.
    The Direction Generale de L'Aviation Civile (DGAC), which is the 
airworthiness authority for France, notified the FAA that an unsafe 
condition may exist on Turbomeca Arriel 1 B, 1 C, 1 C1, 1 C2, 1 D, and 
1 D1 turboshaft engines.
    Since AD 95-11-01 was issued, the DGAC advises that it has received 
a report of an in-flight engine shutdown on an engine that had improved 
2nd stage turbine nozzle guide vanes, modification TU 197, installed. 
In this particular event, a crack initiated in a machined slot located 
between the vanes on the inner ring. The crack propagated and resulted 
in separation of the inner ring. This failure mode is different than 
that experienced on engines that have premodification TU 197 2nd stage 
turbine nozzle guide vanes installed. Installation of modification TU 
197 is identified as a terminating action to the repetitive checks for 
the current AD. As a result of this event, the proposed AD requires 
additional borescope inspections for engines that have modification TU 
197 installed.
    The DGAC has also determined that modification TU 76 should be 
replaced with modification TU 202 on Arriel 1 B, 1 D, and 1 D1 engines. 
The manufacturer has informed the FAA that modification TU 202 may have 
already been installed on all Arriel 1 B, 1 D, and 1 D1 engines 
installed on helicopters of U.S. registry. However, for completeness, 
the proposed AD requires the removal of modification TU 76 or TU 197 
and replacement with modification TU 202 before further flight after 
the effective date of this AD, to cover any potential engines that may 
not have been modified already.
    The proposed AD will also require replacement of the 2nd stage 
nozzle guide vanes, having modification TU 197, with modification TU 
202 on all Arriel 1 A, 1 A1, 1 A2, 1 C, 1 C1, 1 C2, 1 E2, 1 K, 1 K1, 1 
S, and 1 S1 engines at next engine shop visit after the effective date 
of the proposed AD, but no later than December 31, 2006. Installation 
of modification TU 202 constitutes terminating action to the repetitive 
checks and inspections.
    The Arriel 1 E2, 1 K, 1 K1, 1 S, and 1 S1 engine models have also 
been added to the applicability section of the proposed AD since they 
are susceptible to the same problem.

Manufacturer's Service Information

    Turbomeca has issued the following Arriel 1 service bulletins (SBs) 
and alert service bulletins (ASBs):
    [sbull] SB No. 292 72 0181, Update 3, dated September 15, 1995, 
that describes procedures for checking for unusual noise during gas 
generator rundown on engine shutdown and after the last flight of the 
day.
    [sbull] ASB No. A292 72 0212, Update 5, dated August 8, 2001, that 
describes procedures for post Module TU 197 initial and repetitive 
borescope inspections of the nozzle guide vanes for cracks.
    [sbull] ASB No. A292 72 0150, Update 6, dated September 4, 2000, 
that describes procedures for replacing modifications TU 76 and TU 197 
with modification TU 202.
    The DGAC has classified ASB No. A292 72 0212, Update 5, dated 
August 8, 2001, as mandatory and issued AD DGAC 98-311 (A) R1, dated 
October 7, 1998, in order to assure the airworthiness of these 
Turbomeca engines in France.

Differences Between the Manufacturer's Service Information and This 
Proposed AD

    Turbomeca SB No. 292 72 0181 allows 50 flight hours between checks 
for unusual noise during gas generator rundown on Arriel 1 A, 1 A1, and 
1 A2 engines with modification TU 76; and 1 C, 1 C1, 1 C2, 1 K, 1 K1, 
and 1 S engines before modification to TU 197 or TU 202. This proposed 
AD would require that the checks be performed during engine shutdown 
after the last flight of the day or after a 5 second ventilation.

Bilateral Agreement Information

    This engine model is manufactured in France 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 DGAC has kept the FAA informed 
of the situation described above. The FAA has examined the findings of 
the DGAC, 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 Requirements of This AD

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Turbomeca Arriel 1 A, 1 A1, 1 A2, 1 B, 1 C, 1 
C1, 1 C2, 1 D, 1 D1, 1 E2, 1 K, 1 K1, 1 S, and 1 S1 turboshaft engines 
of the same type design that are installed on helicopters registered in 
U.S., the proposed AD would supersede AD 95-11-01 to:
    [sbull] Add additional engine models to the applicability section, 
and
    [sbull] Eliminate the installation of modification TU 197 as a 
terminating action to the repetitive checks, and
    [sbull] Require additional inspections for engines that have 
modification TU 197 installed, and
    [sbull] Require the replacement of modifications TU 76 and TU 197 
with modification TU 202 on Arriel 1 B, 1 D, and 1 D1 engines before 
further flight, and
    [sbull] Replacement of TU 197 with modification TU 202 as a 
terminating action to the repetitive checks and inspections.

Economic Analysis

    There are approximately 487 engines of the affected design in the 
worldwide fleet. The FAA estimates that 47 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, that 
it would take approximately 4 work hours per engine to do the proposed 
inspections, including removal and installation of the gas generator 
module, and that the average labor rate is $60 per work hour. Required 
parts would cost approximately $18,600 per engine. Based on these 
figures, the cost per

[[Page 11344]]

inspection to U.S. operators is estimated to be $885,480. The 
manufacturer has advised the DGAC that it may provide modification TU 
202 at no cost to the operator, thereby substantially reducing the cost 
of this proposed rule.

Regulatory Analysis

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it would not have a 
substantial direct effect 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. 
Accordingly, the FAA has not consulted with state authorities prior to 
publication of this proposed rule.
    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 removing Amendment 39-9235, (60 FR 
27023, May 22, 1995), and by adding a new airworthiness directive:

Turbomeca: Docket No. 94-ANE-08-AD. Supersedes AD 95-11-01, 
Amendment 39-9235.

    Applicability: This airworthiness directive (AD) is applicable 
to Turbomeca turboshaft engine models Arriel 1 A, 1 A1, 1 A2, 1 B, 1 
C, 1 C2, 1 D, 1 D1, 1 E2, 1 K, 1 K1, 1 S, and 1 S1 that have not 
incorporated modification TU 202. These engines are installed on but 
not limited to Eurocopter AS-350 B, B1, and B2; SA-365 C, C2, N, N1, 
and N2; MBB-BK 117 C-1 and C-2, Sikorsky S-76 C, and Agusta A109 K2 
helicopters.

    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 (k) 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: Compliance with this AD is required as indicated, 
unless already done.
    To prevent engine failure due to rubbing of the 2nd stage 
turbine disk on the 2nd stage nozzle guide vanes, which could result 
in complete engine failure and damage to the helicopter, do the 
following:
    (a) For Turbomeca Arriel 1 A, 1 A1, 1 A2, 1 B, 1 C, 1 C1, 1 C2, 
1 D, 1 D1, 1 E2, 1 K, 1 K1, 1 S, and 1 S1 turboshaft engines that 
have incorporated modification TU 202, no further action is 
required.
    (b) For Turbomeca Arriel turboshaft engines Models 1 B, 1 D, or 
1 D1 that have modification TU 76 or TU 197 installed, before 
further flight after the effective date of this AD, replace 
modification TU 76 or TU 197 with modification TU 202 in accordance 
with 2.B.(1) through 2.C.(2) of Arriel 1 Alert Service Bulletin 
(ASB) No. A292 72 0150, Update 6, dated September 4, 2000.

Daily Inspection for Engine Rubbing and Free Rotation

    (c) For Arriel 1 A, 1 A1, 1 A2, 1 C, 1 C1, 1 C2, 1 E2, 1 K, 1 
K1, 1 S, and 1 S1 engines with modification TU 197 installed, 
perform the following daily checks:
    (1) After the last flight of the day or after a ventilation 
(maximum of 5 seconds), immediately after engine stopping, listen 
for unusual engine rubbing noise during the gas generator rundown, 
and
    (2) During the check after the last flight of the day, when the 
T4 temperature is below 150[deg]C (302[deg]F), perform a ventilation 
(5 seconds maximum) during gas generator rundown or check for free 
rotation of the gas generator and unusual noise by turning the 
compressor by hand.
    (3) If any rubbing noise is heard and the source of the noise 
cannot be identified, replace module M03.

Initial Borescope Inspection

    (d) For Arriel 1 A, 1 A1, 1 A2, 1 C, 1 C1, 1 C2, 1 E2, 1 K, 1 
K1, 1 S, and 1 S1 engines with modification TU 197 installed, do the 
following:
    (1) Perform initial borescope inspections for cracks of the 
second stage nozzle guide vanes (NGV2) in accordance with 2.B.(a) 
through 2.B.(c)(2) of Turbomeca ASB No. A292 72 0212, Update 5, 
dated August 8, 2001, and the schedules specified in the following 
Table 1:

                 Table 1.--Initial Borescope Inspection
------------------------------------------------------------------------
  Number of cycles-since-new or overhaul
  (CSN) on the effective date of this AD.        Initial inspection
------------------------------------------------------------------------
(1) Modules M03 with fewer than 1,000 CSN.  Before accumulating 1,100
                                             CSN.
(2) Modules M03 with 1,000 CSN or greater.  Within 100 additional cycles-
                                             in-service (CIS) after the
                                             effective date of this AD.
------------------------------------------------------------------------

    (2) If the 2nd stage nozzle guide vanes do not meet the 
acceptance criteria specified in 2.B.(c)(2) of ASB A292 72 0212, 
Update 5, dated August 8, 2001, replace module M03.

First Repetitive Borescope Inspection

    (e) Thereafter, for Arriel 1 A, 1 A1, 1 A2, 1 C, 1 C1, 1 C2, 1 
E2, 1 K, 1 K1, 1 S, and 1 S1 engines with modification TU 197 
installed, do the following:
    (1) Perform the first repetitive borescope inspection for cracks 
of the NGV2 in accordance with 2.B.(a) through 2.(c)(2) of Turbomeca 
ASB No. A292 72 0212, Revision 5, dated August 8, 2001, and the 
schedules specified in the following Table 2:

               Table 2.--Repetitive Borescope Inspections
------------------------------------------------------------------------
 If module M03 has already been checked       Then repeat inspection
------------------------------------------------------------------------
(i) Once, before 900 CSN...............  Before 1,100 CSN and then
                                          between 1,900 and 2,100 CSN.
(ii) Twice, before 900 CSN without       Before 1,500 CSN.
 propagation of cracks recorded between
 the first and second check.
(iii) Twice, before 900 CSN with         Before 1,100 CSN and then
 propagation of cracks recorded between   between 1,900 and 2,100 CSN.
 the first and second check.
(iv) Once, after 900 CSN...............  Between 1,900 and 2,100 CSN.
------------------------------------------------------------------------


[[Page 11345]]

    (2) If the 2nd stage nozzle guide vanes do not meet the 
acceptance criteria specified in 2.B.(c)(2) of ASB A292 72 0212, 
Update 5, dated August 8, 2001, replace module M03.

Subsequent Repetitive Borescope Inspection

    (f) Thereafter, for Arriel 1 A, 1 A1, 1 A2, 1 C, 1 C1, 1 C2, 1 
E2, 1 K, 1 K1, 1 S, and 1 S1 engines with modification TU 197 
installed, do the following:
    (1) Repeat the borescope inspection of the NGV2 in accordance 
with 2.B.(a) through 2.B.(c)(2) of Turbomeca ASB No. A292 72 0212, 
Update 5, dated August 8, 2001, at intervals not to exceed 2,100 
cycles-since-last-inspection (CSLI).
    (2) If the 2nd stage nozzle guide vanes do not meet the 
acceptance criteria specified in 2.B.(c)(2) of ASB A292 72 0212, 
Update 5, dated August 8, 2001, replace module M03.

Replacement of Modification TU 197

    (g) For 1 A, 1 A1, 1 A2, 1 C, 1 C1, 1 C2, 1 E2, 1K, 1 K1, 1 S, 
and 1 S1 engines that have modification TU 197 installed, install 
the improved 2nd stage nozzle guide vanes, modification TU 202 at 
next shop visit after the effective date of this AD, but not later 
than December 31, 2006, in accordance with 2.B. through 2.C. of 
Arriel 1 ASB No. A292 72 0150, Update No. 6, dated September 4, 
2000.

Terminating Action

    (h) Installation of the improved 2nd stage nozzle guide vane, 
modification TU 202, constitutes terminating action to the checks 
and inspections required by paragraphs (c)(1), (c)(2), and (d)(1) 
through (d)(3) of this AD.
    (i) The checks required by paragraph (c)(1) and (c)(2) of this 
AD may be performed by the pilot holding at least a private pilot 
certificate as an exception to the requirements of part 43 of the 
Federal Aviation Regulations (14 CFR part 43). The checks must be 
recorded in accordance with Sec. Sec.  43.9 and 91.417(a)(2)(v) of 
the Federal Aviation Regulations (14 CFR 43.9 and 14 CFR 
91.417(a)(2)(v)), and the records must be maintained as required by 
the applicable Federal Aviation Regulation.

Alternative Methods of Compliance

    (j) 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 must 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.

Special Flight Permits

    (k) Special flight permits may be issued in accordance with 
Sec. Sec.  21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the helicopter to a location where 
the requirements of this AD can be done.

    Note 3: The subject of this AD is addressed in DGAC 
airworthiness directive DGAC 98-311 (A) R1, dated October 7, 1998.


    Issued in Burlington, Massachusetts, on March 3, 2003.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 03-5577 Filed 3-7-03; 8:45 am]
BILLING CODE 4910-13-P