PRODUCT: Turbomeca S.A. Arriel 2C1, 2C2, and 2S2 turboshaft engines. SUBJECT: Airworthiness Directive 2012-12-20 ACTION: Final Rule
SUMMARY: This AD requires replacement of affected digital engine control units (DECUs). This AD was prompted by a report of a helicopter experiencing a DECU malfunction during flight. The FAA is issuing this AD to prevent loss of automatic control on one or both engines installed on the same helicopter, which could result in an uncommanded in-flight engine shutdown, forced autorotation landing, or accident.