Airworthiness Directive · Amendment 39-15950 · Turbomeca S.A. Arrius 2F Turboshaft Engines
Turbomeca S.A. Arrius 2F Turboshaft Engines
This AD applies to Turbomeca S.A. Arrius 2F turboshaft engines that have not incorporated modification Tf75. These engines are installed on, but not limited to, Eurocopter EC120B helicopters.
The FAA is superseding an existing airworthiness directive (AD) for Turbomeca S.A. Arrius 2F turboshaft engines that have not incorporated Turbomeca Modification Tf75. That AD currently requires replacing the O-ring on the check valve piston in the lubrication unit at repetitive intervals. This AD requires the same repetitive replacements and would require incorporating Modification Tf75 as terminating action to the repetitive O-ring replacements. Modification Tf75 replaces the check valve piston with a piston design not requiring an O-ring. This AD results from the European Aviation Safety Agency (EASA) and Turbomeca S.A. mandating the incorporation of Modification Tf75. We are issuing this AD to prevent an uncommanded in-flight shutdown of the engine, which could result in a forced autorotation landing and damage to the helicopter.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
Replace the O-ring on the check valve piston in the lubrication unit at the intervals specified in Table 1 of this AD. Use the Instructions to be Incorporated paragraphs 2.A. through 2.C.(2) of Turbomeca Alert Service Bulletin No. A319 79 4802, Update No. 1, dated April 3, 2006, to replace the O-ring.
| If the class of oil is: | Then replace the O-ring by the later of: | Thereafter, replace the O-ring within: |
|---|---|---|
| (1) HTS or unknown. | 300 hours time-since-new (TSN) or 50 hours after March 21, 2007 (effective date of AD 2005-17-17R1). | 300 hours time-since-last replacement (TSR). |
| (2) STD. | 450 hours TSN or 50 hours after March 21, 2007 (effective date of AD 2005-17-17R1). | 500 hours TSR. |
Within 150 flight hours after the effective date of this AD, do the following mandatory terminating action to the repetitive O-ring replacements:
(1) Incorporate Turbomeca Modification Tf75 by replacing the check valve piston in the lubrication unit, with a check valve piston requiring no O-ring.
(2) Use the Instructions to be Incorporated paragraphs 2.A. through 2.B.(1)(r) of Turbomeca Mandatory Service Bulletin No. 319 79 4075, Version B, dated May 14, 2008, to replace the check valve piston.
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.
Engines
