AD 98-21-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | MD Helicopters, Inc. | 369D | Airworthiness Directives; McDonnell Douglas Helicopter Systems Model 369D, 369E, 369FF, 500N, AH-6, and MH-6 Helicopters |
| aircraft | MD Helicopters, Inc. | 369E | Airworthiness Directives; McDonnell Douglas Helicopter Systems Model 369D, 369E, 369FF, 500N, AH-6, and MH-6 Helicopters |
| aircraft | MD Helicopters, Inc. | 369FF | Airworthiness Directives; McDonnell Douglas Helicopter Systems Model 369D, 369E, 369FF, 500N, AH-6, and MH-6 Helicopters |
| aircraft | MD Helicopters, Inc. | 500N | Airworthiness Directives; McDonnell Douglas Helicopter Systems Model 369D, 369E, 369FF, 500N, AH-6, and MH-6 Helicopters |
Unsafe Condition
Wear of the bearing carrier due to spinning of the bearing outer race, leading to failure of the overrunning clutch, excessive vibration, wear of other clutch components, and subsequent loss of power to the helicopter rotor drive system.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Visually inspect the overrunning clutch retainer (P/N 369F5460-1), carrier (P/N 369F5461-1), housing (P/N 369F5451-1), and pin (P/N MS16556-801) for wear or damage in accordance with MDHS Service Information Notice No. DN-190, EN-83, FN-70, NN-011. Replace unairworthy clutch assemblies with airworthy ones.
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Compliance Time
Before or upon reaching 100 hours time-in-service (TIS) for helicopters with a clutch assembly having less than 100 hours TIS.
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Affected Aircraft
McDonnell Douglas Helicopter Systems Model 369D, 369E, 369FF, 500N, AH-6, and MH-6 helicopters with overrunning clutch assembly P/N 369F5450-501 installed.
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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