AD 88-25-09
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters | AS355E | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
| aircraft | Airbus Helicopters | AS355F | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
| aircraft | Airbus Helicopters | AS355F1 | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
| aircraft | Airbus Helicopters | AS355F2 | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
Unsafe Condition
Tail rotor drive shaft failure, which could result in loss of control.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Perform vibration level measurements every 100 hours' time in service. If vibration exceeds 3 IPS, replace the shaft before further flight or inspect every 10 hours' time in service. If between 1.75 and 3 IPS, clean fan assembly, recheck vibration, balance fan if needed, and inspect splines and bearings. Replace shaft if vibration remains above 1.75 IPS.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 50 hours' time in service after receipt of this AD, and thereafter at intervals not to exceed 100 hours' time in service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE) Model AS 355 series helicopters with Part Number 355A34-1037-00 tail rotor drive shaft.
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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