Airworthiness Directive · Amendment 39-19484 · Turbine section
Safran Helicopter Engines, S.A., Turboshaft Engines
This AD applies to Safran Helicopter Engines, S.A. (Safran Helicopter Engines), ASTAZOU XIV B and H model engines with the 3rd-stage turbine wheels specified in Figure 1 to paragraph (c) of this AD installed.
| Part Nos. | Serial Nos. |
|---|---|
| 0 265 25 706 0 | AD78691AD, AD78703AD, AD93845AD, CC52860, RD39596 |
| 0 265 25 705 0 | L232AD |
We are adopting a new airworthiness directive (AD) for all Safran Helicopter Engines, S.A. (Safran Helicopter Engines), ASTAZOU XIV B and H model engines with certain 3rd-stage turbine wheels installed. This AD requires initial and repetitive inspections of the 3rd-stage turbine wheels. This AD was prompted by a report that six 3rd-stage turbine wheels were returned to service after a repair that could result in exceedance of the allowable vibration threshold during operation. We are issuing this AD to address the unsafe condition on these products.
(1) Perform an inspection of the 3rd-stage turbine wheel as follows:
(i) Before exceeding 400 engine cycles since the last engine overhaul, or within 50 engine start stop cycles after the effective date of this AD, whichever occurs later, inspect the rear face of each affected 3rd-stage turbine wheel in accordance with the Accomplishment Instructions, paragraphs 2.4.2 and 2.4.3, in Safran Helicopter Engines Mandatory Service Bulletin (MSB) 283 72 0813, Version A, dated February 26, 2018.
(ii) After that, repeat the inspection required by paragraph (g)(1)(i) of this AD at intervals not to exceed 400 engine cycles since the last inspection.
(iii) A one-time, non-cumulative tolerance of 50 engine cycles may be applied to the repetitive inspection interval required by paragraph (g)(1)(ii) of this AD.
(2) If a crack indication is found during any inspection required by paragraph (g)(1) of this AD, remove the engine from service and repair the 3rd-stage turbine wheel in accordance with the Accomplishment Instructions, paragraph 4.3, in Safran Helicopter Engines MSB 283 72 0813, Version A, dated February 26, 2018.
A repair of the 3rd-stage turbine wheel in accordance with the Accomplishment Instructions, paragraph 4.3, in Safran Helicopter Engines MSB 283 72 0813, Version A, dated February 26, 2018, constitutes terminating action for the requirements of this AD for that engine.
For the purpose of this AD, calculate “non-cumulative tolerance” by adding 50 engine cycles to the inspection interval of 400 engine cycles since the last inspection. For example, you may add 50 additional engines cycles to the 400 cycles since last inspection requirement to obtain an inspection interval of 450 engine cycles. Once this non-cumulative tolerance has been applied, all repetitive inspection intervals are required within 400 engine cycles of the previous inspection.
No reporting requirement contained within the MSB referenced in paragraphs (g)(1) and (2) of this AD are required by this AD.
