[Federal Register Volume 60, Number 98 (Monday, May 22, 1995)]
[Rules and Regulations]
[Pages 27023-27025]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12329]



-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-08; Amendment 39-9235; AD 95-11-01]


Airworthiness Directives; Turbomeca Arriel 1 Series Turboshaft 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to Turbomeca Arriel 1 series turboshaft engines, that 
currently requires repetitive checks for engine rubbing noise during 
gas generator shutdown, and for free rotation of the gas generator by 
rotating the compressor manually after the last flight of the day. This 
amendment continues to require these checks, but eliminates the 
reference to the Turbomeca service bulletin, allows the pilot to 
perform all the checks required in this AD, clarifies the inspection 
interval requirement for daily checks, and specifies terminating action 
for the repetitive checks required by this AD. In addition, this AD 
allows the check for engine rubbing noise to be performed during engine 
motoring, and specifies that the engine turbine (T4) temperature must 
be below 150 degrees Centigrade when performing the check for free 
rotation. This amendment is prompted by comments submitted by operators 
of the affected engines in response to the existing AD and the 
availability of an improved design 2nd stage nozzle guide vane. The 
actions specified by this AD are intended to prevent engine failure due 
to rubbing of the 2nd stage turbine disk on the 2nd stage turbine 
nozzle guide vane, which could result in complete engine failure and 
damage to the aircraft.

DATES: Effective June 21, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 21, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from Turbomeca 64511 Bordes Cedex - France. This information 
may be examined at the Federal Aviation Administration (FAA), New 
England Region, Office of the Assistant Chief Counsel, 12 New England 
Executive Park, Burlington, MA 01803-5299; or at the Office of the 
Federal Register, 800 North Capitol Street NW., suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Glorianne Messemer, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (617) 238-7132, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 93-23-09, 
Amendment 39-8745 (58 FR 63061, November 30, 1993), which is applicable 
to Turbomeca Arriel 1 series turboshaft engines, was published in the 
Federal Register on September 6, 1994 (59 FR 46005). That notice of 
proposed rulemaking (NPRM) proposed to continue to require repetitive 
checks for engine rubbing noise during gas generator shutdown, and for 
free rotation of the gas generator by rotating the compressor manually 
at a daily interval until installation of the improved 2nd stage nozzle 
guide vane. That NPRM proposed to allow pilots to perform all the 
required checks. Performing these checks does not require special 
training beyond that already incurred by pilots of the aircraft having 
affected engines, or the use of tools or special measuring equipment, 
or reference to technical data. Accordingly, the FAA has determined 
that pilots may perform all the checks required by that NPRM as an 
exception to Section 43.3 of the Federal Aviation Regulations (14 CFR 
43.3) regarding the performance of maintenance.
    In addition, the NPRM proposed to allow the check for engine 
rubbing noise to be performed during engine motoring, and specifies 
that the engine turbine (T4) temperature must be below 150 degrees 
Centigrade when performing the check for free rotation. Also, the NPRM 
proposed to require installation of modification TU 202, which 
incorporates an improved 2nd stage nozzle guide vane manufactured from 
a new material that is more resistant to fatigue cracking, at the next 
engine overhaul after the effective date of the NPRM, but not later 
than December 31, 1999, as terminating action for the repetitive 
checks. This calendar end-date is based upon parts availability. The 
installation would be performed in accordance with Turbomeca Service 
Bulletin No. 292 72 0150, dated April 10, 1992.
    This engine model is manufactured in France and is type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement in effect at the time of 
type certification. The Direction Generale de L'Aviation Civile (DGAC), 
which is the airworthiness authority for France, 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.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received. [[Page 27024]] 
    One commenter (the manufacturer) states that Arriel engine models 
1A, 1A1, 1A2, 1C, 1C1, and 1C2 should be removed from the AD's 
applicability since these models are all installed in twin-engine 
helicopters. The FAA does not concur. The engine design characteristics 
that produce the unsafe condition are common to the Arriel 1 engine 
models specified in the applicability section of the proposed rule, and 
therefore must remain in the AD to correct for the unsafe condition.
    The commenter also states that the compliance end-date for 
installation of the terminating action should be extended from December 
31, 1999, to December 31, 2002, to facilitate logistical support of the 
improved hardware. The FAA concurs and has revised the compliance 
section of this final rule accordingly.
    The commenter also states that modification TU 197 should be 
designated in addition to TU 202 as terminating action for the 
inspection requirements of this AD. Modification TU 197 is an improved 
2nd stage nozzle guide vane introduced to correct for the unsafe 
condition that is installed on production engines, whereas TU 202, 
which is a similar design improvement, was introduced for in-service 
engines. The FAA concurs and has revised the compliance section of this 
final rule accordingly.
    Since publication of the NPRM, the FAA has increased its estimate 
of labor cost from $55 to $60 per work hour to better reflect current 
maintenance labor rates. The FAA has revised the economic analysis of 
this final rule.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will not increase 
the scope of the AD.
    The FAA estimates that 160 engines installed on aircraft of U.S. 
registry will be affected by this AD, that it will take approximately 
0.2 work hours per engine to accomplish the required actions, and that 
the average labor rate is $60 per work hour. Required parts will cost 
approximately $8,000 per engine. Based on an assumed utilization rate 
and an assumed modification rate, the total cost impact of the AD on 
U.S. operators over the five year compliance period is estimated to be 
$3,105,440.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES. List of Subjects in 14 CFR Part 39
    Air Transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-8745 (58 FR 
63061, November 30, 1993) and by adding a new airworthiness directive, 
Amendment 39-9235, to read as follows:

95-11-01  Turbomeca: Amendment 39-9235. Docket 94-ANE-08. Supersedes 
AD 93-23-09, Amendment 39-8745.

    Applicability: Turbomeca Arriel turboshaft engines Models 1B 
that do have modification TU 76 but do not have modification TU 197 
or TU 202; Arriel Models 1D and 1D1 that do not have modification TU 
197 or TU 202; Arriel Models 1A, 1A1, 1A2 that have had modification 
TU 76 but do not have modification TU 197 or TU 202; and Arriel 
Models 1C, 1C1, and 1C2 that do not have modification TU 197 or TU 
202. These engines are installed on but not limited to Aerospatiale 
Models AS350B, SA365, and AS565 helicopters.
    Note: This 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 (f) to 
request approval from the 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 engine failure due to rubbing of the 2nd stage 
turbine disk on the 2nd stage turbine nozzle guide vane, which could 
result in engine failure and damage to the aircraft, accomplish the 
following:
    (a) For Turbomeca Arriel turboshaft engines Models 1B that have 
modification TU 76 but do not have modification TU 197 or TU 202; 
and Arriel Models 1D and 1D1 that do not have modification TU 197 or 
TU 202; accomplish the following:
    (1) Perform a daily check for unusual engine rubbing noises 
during gas generator shutdown or as engine gas generator speed 
decreases after completion of engine motoring.
    (2) Perform a daily check for free rotation of the gas 
generator, when T4 temperature is below 150 degrees Centigrade, by 
rotating the compressor manually.
    (3) While checking for free rotation of the gas generator, 
perform a check for engine rubbing noise.
    (b) For Turbomeca Arriel turboshaft engines Models 1A, 1A1, 1A2 
that have modification TU 76 but do not have modification TU 197 or 
TU 202; and Arriel Models 1C, 1C1, and 1C2 that do not have 
modification TU 197 or TU 202; accomplish the following:
    (1) Within 50 hours time in service (TIS) after the effective 
date of this AD, perform a check for unusual engine rubbing noise 
during gas generator shutdown or as engine gas generator speed 
decreases after completion of engine motoring.
    (2) Thereafter, at intervals not to exceed 50 hours TIS since 
the last check, perform a check for unusual engine rubbing noise 
during gas generator shutdown or as engine gas generator speed 
decreases after completion of engine motoring.
    (3) Perform a daily check for free rotation of the gas generator 
when T4 temperature is below 150 degrees C, by rotating the 
compressor manually.
    (4) While checking for free rotation of the gas generator, 
perform a check for engine rubbing noise.
    (c) If any engine rubbing noise is detected during the checks 
required by paragraphs (a) and (b) of this AD, prior to further 
flight replace gas generator module M03 with a serviceable module.

    (d) Install the improved 2nd stage nozzle guide vane, 
modification TU 202 or TU 197, [[Page 27025]] at the next engine 
overhaul after the effective date of this AD, but not later than 
December 31, 2002, in accordance with Turbomeca Service Bulletin 
(SB) 292 72 0150, dated April 10, 1992, or in accordance with SB 292 
72 0153, dated February 22, 1993, respectively. Installation of this 
hardware constitutes terminating action to the checks required by 
this AD.
    (e) The checks required by paragraphs (a) and (b) 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 Sections 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.
    (f) 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 method of compliance with this AD, if any, may be 
obtained from the Engine Certification Office.

    (g) 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.
    (h) The actions required by this AD shall be done in accordance 
with the following Turbomeca SB's:

------------------------------------------------------------------------
               Document No.                  Pages          Date        
------------------------------------------------------------------------
292 72 0150...............................     1-4  April 10, 1992.     
  Total pages: 4.                                                       
292 72 0153...............................     1-5  February 22, 1993.  
  Total pages: 5.                                                       
------------------------------------------------------------------------

    This incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
Copies may be obtained from Turbomeca 64511 Bordes Cedex--France. 
Copies may be inspected at the FAA, New England Region, Office of the 
Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; 
or at the Office of the Federal Register, 800 North Capitol Street NW., 
suite 700, Washington, DC.
    (i) This amendment becomes effective on June 21, 1995. Issued in 
Burlington, Massachusetts, on May 15, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-12329 Filed 5-18-95; 8:45 am]
BILLING CODE 4910-13-P