AD 94-12-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-58BT | Airworthiness Directives: Sikorsky Aircraft Model S-58T Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58DT | Airworthiness Directives: Sikorsky Aircraft Model S-58T Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58ET | Airworthiness Directives: Sikorsky Aircraft Model S-58T Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58FT | Airworthiness Directives: Sikorsky Aircraft Model S-58T Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58HT | Airworthiness Directives: Sikorsky Aircraft Model S-58T Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58JT | Airworthiness Directives: Sikorsky Aircraft Model S-58T Series Helicopters |
Unsafe Condition
Failure of the drive shaft assembly, loss of power to the rotor system, and subsequent forced landing due to cracks, loose balance weights, or improperly installed rivets in the engine drive shaft assembly.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the drive shaft assembly for cracks, loose balance weights, and improperly installed rivets using visual and fluorescent penetrant inspections per Sikorsky Alert Service Bulletin 58B35-31A. Replace the assembly if cracks, loose weights, or improper rivets are found. Conduct initial inspections within 25 hours' time-in-service after the effective date or at next removal, followed by repetitive inspections at intervals specified based on part numbers and overhaul status.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 25 hours' time-in-service after the effective date of this AD, or at the next removal of the drive shaft assembly, whichever comes first. Repetitive inspections must be conducted at intervals not to exceed 250 or 2,500 hours' TIS depending on part numbers and overhaul status.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Model S-58T series helicopters (S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, S-58JT) equipped with engine drive shaft assembly part numbers 58350-10030-045/-046, 58350-10030-047/-048/-049.
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
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.