AD 2014-07-06
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Turbomeca | S | Airworthiness Directives; Turbomeca S.A. Turboshaft Engines |
Unsafe Condition
Reports of ruptures on hydromechanical metering unit (HMU) constant delta pressure valves that have less than 2,000 hours in service.
Required Actions
Replace the HMU; reduce the compliance interval; and include the power turbine C2 cycle consumption rate when determining compliance times.
Compliance Time
Within 100 HMU C2 cycles after the effective date of this AD; thereafter, replace the HMU at every 1,000 HMU C2 cycles or 1,500 HMU operating hours, whichever comes first.
Affected Aircraft
Turbomeca S.A. Arriel 2B1 turboshaft engines that do not have modification TU157 incorporated.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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