AD Amdt-39-14721
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Turbomeca | Arriel 1B | Airworthiness Directives; Turbomeca Arriel 1B, 1D, 1D1, and 1S1 Turboshaft Engines |
Unsafe Condition
Request by Turbomeca to clarify compliance times for 2nd stage turbine initial replacement on Arriel 1B, 1D, and 1D1 turboshaft engines. Issued to prevent in-flight engine shutdown and subsequent forced autorotation landing or accident.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Perform initial relative position checks of 2nd stage turbine blades using specified Turbomeca mandatory alert service bulletins before reaching intervals in Table 1 or within 50 hours after AD effective date. Recheck blades at repetitive intervals per Table 1. Initially replace 2nd stage turbines on Arriel 1B, 1D, and 1D1 engines with new or overhauled parts.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within specified intervals in Table 1 or within 50 hours after AD effective date, whichever occurs later.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Turbomeca Arriel 1B engines fitted with 2nd stage turbine modification TU 148, and Arriel 1D, 1D1, and 1S1 engines. Arriel 1B installed on Eurocopter AS-350B and AS-350A helicopters, Arriel 1D on AS-350B1, Arriel 1D1 on AS-350B2, and Arriel 1S1 on Sikorsky S-76A and S-76C helicopters.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.