AD 2015-23-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Schweizer Aircraft Corporation | Various | Airworthiness Directives; Sikorsky Aircraft Corporation (Type Certificate Previously Held by Schweizer Aircraft Corporation) |
| aircraft | Sikorsky | Various | Airworthiness Directives; Sikorsky Aircraft Corporation (Type Certificate Previously Held by Schweizer Aircraft Corporation) |
Unsafe Condition
Insufficient lubrication of a tail rotor (T/R) driveshaft splined fitting could result in excessive wear of the T/R driveshaft splines, leading to failure of the T/R driveshaft and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Within 100 hours time-in-service (TIS), inspect each T/R driveshaft splined fitting for cracks, breaks, excessive wear, galling, spalling, chipping, corrosion, heat discoloration, and distortion. Replace the splined fitting and the T/R driveshaft if excessive wear is found. Inspect each grease fitting for certain conditions and replace if necessary. At intervals not exceeding 100 hours TIS, inspect the T/R driveshaft for straightness, twists, and scratches; inspect each forward and aft T/R driveshaft splines for wear; and correct the torque of each main transmission aft pinion nut.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 100 hours time-in-service (TIS)
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Affected Aircraft
Sikorsky Aircraft Corporation (Type Certificate Previously Held by Schweizer Aircraft Corporation) Model 269A, 269A-1, 269B, 269C, 269C-1, 269D, and TH-55A helicopters, certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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