Airworthiness Directive · Amendment 39-14526 · Turbomeca Arriel 1B, 1D, and 1D1 Turboshaft Engines
Turbomeca Arriel 1B, 1D, and 1D1 Turboshaft Engines
This AD applies to Turbomeca Arriel 1B, 1D, and 1D1 certain turboshaft engines, modified to the TU 202 standard. These engines are installed on, but not limited to, Eurocopter France AS350BA, AS350B, AS350B1, and AS350B2 helicopters.
The FAA is adopting a new airworthiness directive (AD) for Turbomeca Arriel 1B, 1D, and 1D1 turboshaft engines. This AD requires inspecting the 2nd stage nozzle guide vanes (NGV2) for wall thickness. This AD results from one instance of a fractured 2nd stage turbine blade followed by an uncommanded engine shutdown. We are issuing this AD to detect and prevent perforation of the NGV2 that could cause fracture of a turbine blade that could result in an uncommanded engine in-flight shutdown on a single-engine helicopter.
You are responsible for having the actions required by this AD performed at the next shop visit or the next accessibility of the NGV2 after the effective date of this AD, whichever occurs first, but no later than December 31, 2006, unless the actions have already been done.
Inspect the thickness of the material on each NGV2 using the Instructions to be Incorporated of Turbomeca Mandatory Service Bulletin (MSB) No. A292 72 0231, Update No. 5, dated July 22, 2004. Replace the NGV2 if the vane thickness is below the defined criteria.
(g) Inspections carried out before the effective date of this AD, using an earlier update of MSB No. A292 72 0231, are acceptable alternatives to the requirements of this AD.
(h) Information regarding NGV2s that have already had the actions required by this AD done and are exempt from the inspections using paragraph (e) of this AD can be found in MSB No. A292 72 0231, Update No. 5, dated July 22, 2004.
(i) For the purposes of this AD the following definitions apply:
(1) A shop visit is defined as introduction of the engine into a shop for the purposes of deep maintenance and the separation of a major mating flange.
(2) Accessibility of the NGV2 is defined as removal of the NGV2 from the engine regardless of the location or reason for removal.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
