AD 2021-18-06
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus | Helicopters Model EC 155B | Airworthiness Directives; Airbus Helicopters |
| aircraft | Aviat | Various | Airworthiness Directives; Airbus Helicopters |
Unsafe Condition
Reports of an in-flight loss of engine and main gearbox (MGB) cowlings. Subsequent investigations revealed that the MGB cowling attachment fittings failed because of mounting stress in the MGB front fitting and air intake bulkhead.
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Required Actions
Inspect the MGB front fittings within 110 flight hours after April 14, 2017. If there is a discrepancy, applicable corrective action(s) before next flight. Modify the MGB fixed cowling attachments within 660 flight hours or 23 months, whichever occurs first, after the effective date described in EASA AD 2019-0008. Accomplishing the modification constitutes a terminating action for the required inspection. Replace the front bracket, inspect for stress of the MGB fixed cowlings on the radiator bulkhead, and install an additional locking system.
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Compliance Time
Within 110 flight hours after April 14, 2017, or within 660 flight hours or 23 months, whichever occurs first, after the effective date described in EASA AD 2019-0008
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Affected Aircraft
Airbus Helicopters Model EC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, and AS 365 N3 helicopters
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Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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