AD 75-22-21
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters | SA.316B Alouette III | Airworthiness Directives; Societe Nationale Industrielle Aerospatiale: (S.N.I.A.S., formerly SUD AVIATION) Model SA316B Alouette III Helicopters |
Unsafe Condition
Failure of the main gearbox due to incorporation of main rotor transmission gearbox (MGB) with specific part numbers and serial numbers 9,999 or lower, which may require replacement to prevent failure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install a temporary operating limitations placard on the instrument panel within 10 hours' time in service after the effective date. Replace the MGB with a serviceable unit having part numbers specified in Service Bulletin No. 01.34 or FAA-approved equivalent within 450 hours' time in service after the effective date. Remove the placard after completing the MGB replacement.
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Compliance Time
Within the next 10 hours' time in service after the effective date of this AD (for the placard installation) and within the next 450 hours' time in service after the effective date (for the MGB replacement).
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Affected Aircraft
Societe Nationale Industrielle Aerospatiale (S.N.I.A.S.) Model SA316B Alouette III helicopters with main rotor transmission gearbox (MGB) Serial Number 9,999 or lower, P/N 3160S.62.00.000.10 through .12 incorporating Modification AM1212, or P/N 3160S.62.00.000.13 or .14.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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