Airworthiness Directive · Amendment 39-17035 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
This AD applies to Turbomeca S.A. Arriel 2B and 2B1 turboshaft engines with at least one installed power turbine (PT) blade part number (P/N) 2 292 81 A01 0, serial numbers (S/Ns) 102782 through 120230 inclusive, or, S/Ns 120293 through 120390 inclusive.
We are adopting a new airworthiness directive (AD) for all Turbomeca S.A. Arriel 2B and 2B1 turboshaft engines. This AD was prompted by the discovery of non-conformities of certain power turbine (PT) blade fir-tree roots. This AD requires removing the affected PT blades from service on or before reaching a new reduced life limit for those certain PT blades. We are issuing this AD to prevent PT blade rupture, which could result in an uncommanded in-flight engine shutdown, forced autorotation landing, or accident.
Unless already done, do the following actions within 5,000 flight cycles-since-new (CSN) on the PT blades, or within one month after the effective date of this AD, whichever occurs later.
(1) Replace the PT blades with PT blades eligible for installation; or
(2) Replace the M04 module with an M04 module having PT blades eligible for installation; or
(3) Replace the PT wheel assembly with a PT wheel assembly having PT blades eligible for installation.
(4) Guidance on the replacements specified in paragraphs (e)(1) through (e)(3) can be found in Turbomeca S.A. Alert Mandatory Service Bulletin No. A292 72 2842, Version A, dated September 23, 2011.
For the purposes of this AD, a PT blade eligible for installation is one not listed in paragraph (c) of this AD or, one listed in paragraph (c) of this AD with fewer than 5,000 flight CSN.
From the effective date of this AD:
(1) Do not install a PT blade as listed in paragraph (c) of this AD, that has 5,000 or more flight CSN, into any engine.
(2) Do not install any engine with a PT blade as listed in paragraph (c) of this AD, that has 5,000 or more flight CSN, onto a helicopter.
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.
