AD 98-24-21

This amendment adopts a new airworthiness directive (AD) that is applicable to Eurocopter France (ECF) Model AS 332C, AS 332L, AS 332L1, and AS 332L2 helicopters. This action requires inserting instructions into the Model AS 332C, AS 332L, AS 332L1, and AS 332L2 Rotorcraft Flight Manuals (RFMs) regarding actions to take if either the "OVSP 1" or "OVSP 2" amber warning light illuminates. This action also requires, for the Model AS 332C, AS 332L, and AS 332L1 helicopters, measuring the vibration levels of the engine-to-main gearbox (MGB) shaft, inspecting the torque on the MGB coupling bolts, and conducting an engine-to-MGB coupling 23,000 revolutions per minute (RPM) input check. This amendment is prompted by an accident involving a Model AS 332L1 helicopter in which the helicopter experienced an engine overspeed resulting in failure of both engines. The actions specified in this AD are intended to prevent failure of the rotor drive engine-to-MGB coupling, which, if undetected, could result in an engine overspeed leading to an uncontained engine turbine wheel burst and subsequent loss of control of the helicopter.

Final rule; request for comments

98-24-21 EUROCOPTER FRANCE: Amendment 39-10906. Docket No. 98-SW-19-AD.
Applicability: Model AS 332C, AS 332L, AS 332L1, and AS 332L2 helicopters, certificated in any category.

NOTE 1: This AD applies to each helicopter 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 helicopters 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 (e) 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 anymodification, alteration, or repair remove any helicopter from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the rotor drive engine-to-main gearbox (MGB) coupling, which, if undetected, could result in an engine overspeed leading to an uncontained engine turbine wheel burst and subsequent loss of control of the helicopter, accomplish the following:

(a) For Model AS 332C, AS 332L, AS 332L1, and AS 332L2 helicopters, before further flight, insert the following statement into the Emergency Procedures section, Chapter 3, of the Rotorcraft Flight Manual:

"If at any time during flight, either the "OVSP 1" or "OVSP 2" amber warning light illuminates, even intermittently, reduce the affected engine to ground idle as soon as possible, then shut it down once all of the parameters on the remaining engine have been checked and found to be satisfactory."

(b) For Model AS 332C, AS 332L, and AS 332L1 helicopters, within 8 hours time-in-service (TIS) and at intervals not to exceed 25 hours TIS thereafter, measure the vibration level of the left and right 23,000 RPM input shaft (engine-to-MGB shaft). Record the mean value of the measured vibration level in the helicopter maintenance records.

(1) If the vibration level exceeds 0.65 inches per second (IPS), perform the inspections described in paragraph (c) and (d) of this AD before further flight.

(2) If the vibration level is less than or equal to 0.65 IPS, perform the inspections described in paragraph (c) and (d) of this AD within the next 25 hours TIS.

(c) For Model AS 332C, AS 332L, and AS 332L1 helicopters, measure and record the tightening torque on the three engine-to-MGB coupling bolts for the left and right 23,000 RPM input shafts. Accomplish this measurement every 50 hours TIS after the initial inspection if Eurocopter France MODs 0752316 and 0752317 have not been accomplished.

(1) If Eurocopter France MOD 0752316 (tie bolt replacement) has not been accomplished, the tightening torque should be 1.5 to 1.9 m.daN (133 to 168 in.-lbs.) (lubricated with NATO 0.156 oil or equivalent).

(2) If Eurocopter France MOD 0752316 (tie bolt replacement) has been accomplished, the tightening torque should be 1.2 to 1.4 m.daN (106 to 124 in.-lbs.) (lubricated with NATO 0.156 oil or equivalent).

(d) Perform the engine-to-MGB coupling 23,000 RPM input check in accordance with the applicable maintenance manual.

NOTE 2: Section 63.10.00.602 of the applicable maintenance manual contains procedures for accomplishing the engine-to-MGB coupling 23,000 RPM input check. Paragraph 5 or the Work Card date code 97-04 is not applicable to the subject of this AD.

(1) While inspecting the splined flanges, inspect the splines for wear. Also inspect the MGB end of the splined flange for impact marks on the end of the splines. If wear exceeds the allowable limits, or if impact marks are found on the end of the splines, replace the splined flange with an airworthy splined flange.

(2) Inspect for the presence of the O-ring on the splined flange.

(3) After accomplishing the engine-to-MGB coupling 23,000 RPM input check and reassembly, measure the vibration level and record the results. If the vibration level remains above 0.65 IPS, conduct the vibration level correction procedure.

NOTE 3: Maintenance Manual (MET) Work Card 63.20.00.501 provides correction procedures if the vibration level exceeds 0.65 IPS.

(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, Rotorcraft Standards Staff, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff.

NOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff.

(f) Special flight permits will not be issued.

NOTE 5: The subject of this AD is addressed in Direction Generale De L'Aviation Civile (France) AD 97-288-065(AB), AD 97-303-066(AB), AD 97-289-008(AB), all dated October 22, 1997, and AD 86-012-023(A) R4, dated July 29, 1998.
(g) This amendment becomes effective on December 9, 1998.

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 ECF Model AS 332C, AS 332L, AS 332L1, and AS 332L2 helicopters. The DGAC advises that failure of the MGB coupling could cause loss of load on the engine, and result in engine overspeed. The DGAC warning stems from an accident involving a Model AS 332L1 helicopter in which the helicopter experienced an engine overspeed resulting in failure of both engines.

ECF has issued Eurocopter Service Telex (Telex) No. 00047/0275/97, dated October 2, 1997. That service telex specifies checking the tightening torque loads on the MGB coupling tie-bolts; checking the condition of the splined flanges; confirming the presence of the O-ring on the splined sleeve; and checking the vibration level of the engine-to-MGB 23,000 RPM input shaft every 25 flying hours. ECF has also issued Eurocopter Service Bulletin No. 63.00.21 Ed. 1., dated June 26, 1998, which specifies the same inspections as the previously mentioned Telex, but also specifies a recurring 50 hour time-in-service (TIS) check of the tightening torque loads on the MGB coupling tie-bolts for couplings that have not been modified in accordance with certain ECF modifications. That service bulletin also specifies a recurring 550 hour TIS engine-to-MGB coupling 23,000 RPM input check. The DGAC classified this service telex and service bulletin as mandatory and issued AD 97-303-066(AB), dated October 22, 1997, and AD 86-012-023(A) R4, dated July 29, 1998, in order to assure the continued airworthiness of these helicopters in France. The DGAC also issued AD 97-288-065(AB) for Model AS 332C, AS 332C1, AS 332L, and AS 332L1 helicopters, and AD 97-289-008(AB) for Model AS 332L2 helicopters, both dated October 22, 1998, which require inserting emergency instructions into the RFM regarding actions to take if either the "OVSP 1" or "OVSP2" amber warning lights illuminate.

These helicopter models are manufactured in France and are 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.

Since an unsafe condition has been identified that is likely to exist or develop on other ECF Model AS 332C, AS 332L, AS 332L1, and AS 332L2 helicopters of the same type design registered in the United States, this AD is being issued to prevent failure of the rotor drive engine-to-MGB coupling, which, if undetected, could result in an engine overspeed leading to an uncontained engine turbine wheel burst and subsequent loss of control of the helicopter. This AD requires inserting an emergency procedure into the RFM regarding actions to take if either the "OVSP 1" or "OVSP 2" amber warning light illuminates; measuring the vibration levels of the engine-to-MGB shaft; inspecting the torque on the MGB coupling bolts; performing an engine-to-MGB coupling RPM input check; inspecting the spline and splined flanges; and inspecting the vibration level after the reassembly of the coupling. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability of the helicopter. Therefore, the actions stated in this AD are required prior to further flight and this AD must be issued immediately.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable,and that good cause exists for making this amendment effective in less than 30 days.

The FAA estimates that 4 helicopters will be affected by this proposed AD, that it will take approximately 13.5 work hours to measure the vibration levels; inspect the torque of the MGB coupling bolts; and conduct the other inspections. The average labor rate is $60 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $3,240.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 98-SW-19-AD." The postcard will be date stamped and returned to the commenter.

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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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, 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. 106(g), 40113, 44701.

39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: