[Federal Register Volume 67, Number 231 (Monday, December 2, 2002)]
[Proposed Rules]
[Pages 71493-71495]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-30351]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-12-AD]
RIN 2120-AA64


Airworthiness Directives; Turbomeca Turmo IV A and Turmo IV C 
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 adopt a 
new airworthiness directive (AD) that is applicable to Turbomeca Turmo 
IV A and IV C series turboshaft engines. This proposal would require 
initial and repetitive borescope and eddy current or ultrasonic 
inspections of centrifugal compressor intake wheel blades for cracks 
and evidence of corrosion pitting, and, if found cracked or if there is 
evidence of corrosion pitting, replacement with serviceable parts. This 
proposal is prompted by reports of cracked centrifugal compressor 
intake wheel blades, resulting in the release of one or more blade 
fragments. The actions specified by the proposed AD are intended to 
prevent centrifugal compressor intake wheel blade cracks, which can 
result in in-flight engine power loss or shutdown.

DATES: Comments must be received by January 31, 2003.

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-12-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 Turbomeca, 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 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

[[Page 71494]]

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-12-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. 99-NE-12-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Direction Generale de L'Aviation Civile (DGAC), which is the 
airworthiness authority for France, recently notified the FAA that an 
unsafe condition may exist on Turbomeca Turmo IV A and IV C series 
turboshaft engines. The DGAC advises that they have received reports of 
cracked centrifugal compressor intake wheel blades. The phenomena of 
blade cracking occurs in two phases; initiation after a single event, 
such as foreign object damage or surge, and crack propagation due to 
operating at a gas generator speed, between 80 percent and 83 percent, 
that appears to set up a vibration. Although the exact cause of the 
initiation of cracks has not yet been identified, cracks could initiate 
at corrosion pits. The investigation is continuing. This condition, if 
not corrected, could result in centrifugal compressor intake wheel 
blade cracks, which can result in in-flight engine power loss or 
shutdown.

Manufacturer's Service Information

    Turbomeca has issued Turmo IV Service Bulletin (SB) No. 249 72 
0100, Update No. 4, dated January 25, 2000, that specifies procedures 
for the centrifugal compressor intake wheel blade inspections. The DGAC 
classified this SB as mandatory and issued airworthiness directive (AD) 
DGAC AD 97-122(A), Revision 3, dated April 5, 2000, in order to ensure 
the airworthiness of these engines in France. Turbomeca has also issued 
Turmo IV SB No. 249 72 0117, dated March 11, 2000, that specifies 
procedures for installation of modification TU 224.

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 products of this same type design, the 
proposed AD would require:
    [sbull] Initial and repetitive borescope and eddy current or 
ultrasonic inspections of centrifugal compressor intake wheel blades 
for cracks and evidence of corrosion pitting; and
    [sbull] Replacement with serviceable parts if found cracked or if 
there is evidence of corrosion pitting.
    At this time there is no modification available as terminating 
action; as the investigation is ongoing into the cause of crack 
initiation, future rulemaking may be necessary. The actions would be 
required to be done in accordance with the SB described previously.

Economic Analysis

    There are approximately 1,110 engines of the affected design in the 
worldwide fleet. The FAA estimates that there are currently 11 engines 
installed on helicopters of U.S. registry that would be affected by 
this proposed AD, that it would take approximately 41 work hours per 
engine to perform the proposed inspections, including disassembling and 
assembling engines, and that the average labor rate is $60 per work 
hour. A replacement centrifugal compressor assembly costs approximately 
$21,651. Based on these figures, the cost per inspection is estimated 
to be $265,221.

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 adding the following new 
airworthiness directive:

Turbomeca: Docket No. 99-NE-12-AD.

    Applicability: This airworthiness directive (AD) is applicable 
to Turbomeca Turmo IV A and IV C series turboshaft engines. These 
engines are installed on but not limited to Aerospatiale FA 330-PUMA 
helicopters.

    Note 1: 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 request approval for an 
alternative method of compliance in accordance with paragraph (e) 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 is required as indicated, unless already 
done
    To prevent centrifugal compressor intake wheel blade cracks, 
which can result in in-flight engine power loss or shutdown, do the 
following:

[[Page 71495]]

    (a) For engines that have been modified to TU 197 standard, but 
have not been modified to TU 191 or TU 224 standard, do the 
following:
    (1) Remove modification TU 197 and install modification TU 224 
in accordance with Turmo IV SB 249 72 0117, dated March 11, 2000, 
within the next 50 cycles or six months after the effective date of 
the AD, whichever occurs first.
    (2) Within 1,000 flight hours (FH) after the installation of 
modification TU 224 standard, do the following:
    (i) Perform a visual inspection and an ultrasonic inspection 
(USI) in accordance with paragraph 2.B.(3) of Turbomeca Turmo IV SB 
249 72 0100, Update 4, dated January 25, 2000.
    (ii) Thereafter, perform a visual inspection and a USI at 
intervals not to exceed 1,000 FH in accordance with paragraph 
2.B.(3) of Turbomeca Turmo IV SB 249 72 0100, Update 4, dated 
January 25, 2000.
    (b) For engines that have not been modified to TU 191, TU 197, 
or TU 224 standard, do the following in accordance with Turbomeca 
Turmo IV SB 249 72 0100, Update 4, dated January 25, 2000:
    (1) For centrifugal compressor intake wheels that, on the 
effective date of this AD, have been operated for more than 250 FH 
since the last inspection of the centrifugal compressor intake wheel 
blades, do the following:
    (i) Perform an initial borescope inspection of the blades for 
evidence of corrosion within the next 50 FH, or six months after the 
effective date of this AD, whichever occurs first, in accordance 
with paragraph 2.B.(1) of the SB.
    (ii) If corrosion is found, perform an ECI or USI, as 
applicable, of the blades for cracks within 50 FH after the 
borescope inspection performed in accordance with paragraph 2.B.(3) 
of the SB, and if necessary, replace with serviceable parts.
    (iii) If corrosion is not found, perform an ECI or USI, as 
applicable, of the blades for cracks within 250 FH after the 
borescope inspection performed in accordance with paragraph 
(b)(1)(i) of this AD, and if necessary, replace with serviceable 
parts.
    (iv) Thereafter, perform borescope inspections and ECI's or 
USI's, as applicable, of the blades for cracks and evidence of 
corrosion, alternating at intervals not to exceed 250 FH since the 
last inspection.
    (v) Remove from service centrifugal compressor intake wheels 
found cracked and replace with serviceable parts.
    (2) For centrifugal compressor intake wheels that, upon the 
effective date of this AD, have been operated for less than or equal 
to 250 FH since the last inspection of the blades, do the following:
    (i) Perform an initial borescope inspection of the blades for 
evidence of corrosion prior to accumulating 250 FH since the last 
inspection of the blades in accordance with paragraph 2.B.(1) of the 
SB.
    (ii) If corrosion is found, perform an ECI or USI, as 
applicable, of the blades for cracks, and, if necessary, replace 
with serviceable parts, within 50 FH after the borescope inspection 
performed in accordance with paragraph 2.B.(3) of the SB.
    (iii) If corrosion is not found, perform an ECI or USI, as 
applicable, of the blades for cracks, and, if necessary, replace 
with serviceable parts, within 250 FH after the borescope inspection 
performed in accordance with paragraph (b)(2)(i) of this AD.
    (iv) Thereafter, perform borescope inspections and ECI's or 
USI's, as applicable, of the blades for cracks and evidence of 
corrosion, alternating at intervals not to exceed 250 FH since the 
last inspection.

    Note 2: Alternating intervals means that if the last inspection 
was an ECI or a USI, the next inspection will be a borescope 
inspection. If the last inspection was a borescope inspection, the 
next 250 FH inspection will be an ECI or a USI as applicable.

    (v) Remove from service centrifugal compressor intake wheels 
found cracked and replace with serviceable parts.
    (c) For engines not modified to TU 197 but have been modified to 
TU 191 or TU 224 standard, that have been operated for more than 
1,000 flight hours since the last inspection of the blades, do the 
following in accordance with Turbomeca Turmo IV SB 249 72 0100, 
Update 4, dated January 25, 2000:
    (1) Perform an initial ECI or USI, as applicable, of the blades 
for cracks, in accordance with paragraph 2.B.(3) of the SB, within 
the next 50 FH, or 6 months after the effective date of this AD, 
whichever occurs first.
    (2) Thereafter, inspect at intervals not to exceed 1,000 FH.
    (3) Remove from service centrifugal compressor intake wheels 
found cracked, and replace with a serviceable part

Alternative Methods of Compliance

    (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 (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 3: 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

    (f) 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 4: The subject of this AD is addressed in Direction 
Generale de L'Aviation Civile airworthiness directive AD97-122(B), 
dated May 21, 1997.


    Issued in Burlington, Massachusetts, on November 21, 2002.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 02-30351 Filed 11-29-02; 8:45 am]
BILLING CODE 4910-13-P