AD 97-23-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters Deutschland GmbH | MBB-BK 117 A-1 | Airworthiness Directives; Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | MBB-BK 117 A-3 | Airworthiness Directives; Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | MBB-BK 117 A-4 | Airworthiness Directives; Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | MBB-BK 117 B-1 | Airworthiness Directives; Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | MBB-BK 117 B-2 | Airworthiness Directives; Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | MBB-BK 117 C-1 | Airworthiness Directives; Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2 and C-1 Helicopters |
Unsafe Condition
Failure of the clutch, leading to loss of power to the main rotor and a subsequent forced landing of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Within 30 hours time-in-service after the effective date, enter the new life limit of 3,600 hours TIS into the Accessory Replacement Record. Remove the clutch from service on or before reaching 3,600 hours TIS. Replacement with clutch part number 4639202011 terminates AD requirements.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 30 hours time-in-service after the effective date
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters with clutch part numbers 4639302044 or CL42067-1 installed. Serial ranges: A-1/A-3/A-4/B-1/B-2 models S/N 7001-7250; C-1 models S/N 7500-7520.
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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