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Proposed Rule

Airworthiness Directives; Turbomeca Arriel 1 Series Turboshaft Engines

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Information about this document as published in the Federal Register.

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Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

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: 9-ane-adcomment@faa.gov. 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.

Start Further Info

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.

End Further Info End Preamble Start Supplemental Information

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 Start Printed Page 11343postcard 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):

  • 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.
  • 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.
  • 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:

  • Add additional engine models to the applicability section, and
  • Eliminate the installation of modification TU 197 as a terminating action to the repetitive checks, and
  • Require additional inspections for engines that have modification TU 197 installed, and
  • 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
  • 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 Start Printed Page 11344inspection 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[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°C (302°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 checkedThen repeat inspection
(i) Once, before 900 CSNBefore 1,100 CSN and then between 1,900 and 2,100 CSN.
(ii) Twice, before 900 CSN without propagation of cracks recorded between the first and second checkBefore 1,500 CSN.
(iii) Twice, before 900 CSN with propagation of cracks recorded between the first and second checkBefore 1,100 CSN and then between 1,900 and 2,100 CSN.
(iv) Once, after 900 CSNBetween 1,900 and 2,100 CSN.
Start Printed 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 §§ 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 §§ 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.

Start Signature

Issued in Burlington, Massachusetts, on March 3, 2003.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 03-5577 Filed 3-7-03; 8:45 am]

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