AD 2021-05-22 Requires Removal From Service Of Certain Stage 2 HPT Disks

The FAA is adopting a new airworthiness directive (AD) for certain Safran Helicopter Engines, S.A. (Safran Helicopter Engines) Arriel 1B, Arriel 1C, Arriel 1C2, Arriel 1D1, Astazou XIV B, and Astazou XIV H model turboshaft engines.

This AD was prompted by the detection of positive segregation (freckles) on Stage 2 high-pressure turbine (HPT) disks and Stage 3 turbine wheels. This AD requires removal from service of certain Stage 2 HPT disks for Safran Helicopter Engines Arriel 1B, 1C, 1C2, and 1D1 model turbofan engines and affected Stage 3 turbine wheels for Safran Helicopter Engines Astazou XIV B and XIV H model turbofan engines. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective March 22, 2021.

Supplementary Information: The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA AD 2020-0151-E, dated July 9, 2020, for Safran Helicopter Engines Arriel 1B, Arriel 1C, Arriel 1C2, and Arriel 1D1 model turboshaft engines, and AD 2020-0161-E, dated July 17, 2020, for Safran Helicopter Engines Astazou XIV B and Astazou XIV H model turboshaft engines to address an unsafe condition for the specified products.

EASA AD 2020-0151-E states:

• Positive segregation (freckles) was detected on Stage 2 HP turbine discs manufactured from a certain block of material. Other parts manufactured from that same block of material may also be affected by this non-conformity.
• This condition, if not corrected, could lead to HP turbine disc failure and result in high-energy debris release, with consequent damage to, and reduced control of, the helicopter.
• To address this unsafe condition, SAFRAN issued the MSB, as defined in this [EASA] AD, to identify affected HP turbine discs and provide instructions for replacement.
• For the reason described above, this [EASA] AD requires replacement of affected parts with serviceable parts, and prohibits re-installation of affected parts.

EASA AD 2020-0161-E states:

• Positive segregation (freckles) was detected on Stage 3 turbine wheels manufactured from a certain block of material. Other parts manufactured from that same block of material may also be affected by this non-conformity.
• This condition, if not corrected, could lead to turbine wheel failure and result in highenergy debris release, with consequent damage to, and reduced control of, the helicopter.
• To address this unsafe condition, SAFRAN issued the MSB, as defined in this [EASA] AD, to identify affected turbine wheels and provide instructions for replacement.

For the reason described above, this [EASA] AD requires replacement of affected parts with serviceable parts, and prohibits re-installation of affected parts. You may obtain further information by examining the MCAIs in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0132.

FMI: www.regulations.gov