AD 59-19-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing Defense & Space Group | 44A | Airworthiness Directives; VERTOL Models 44A, B, and C Helicopters |
| aircraft | Boeing Defense & Space Group | 44B | Airworthiness Directives; VERTOL Models 44A, B, and C Helicopters |
Unsafe Condition
Failures of the engine cooling fan discs, blades, and adapter rings have been experienced, originating as cracks at the fan blade mounting hole on the forward face of the disc rim, root radius on the convex camber of blades, or in the adapter ring holes, leading to separation and potential fuselage penetration.
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Required Actions
Retire and replace fan assembly P/N 42P6410 with hub and fan assembly P/N 42P6459-4. The new assembly includes a Z ring stiffener P/N 04P9392-1, thickened forged blades P/N 42P6421-3, and a steel adapter P/N 04P6458-1. Destroy or mutilate cracked fan disc assemblies P/N 42P6422, cast blades P/N 42P6421-2, and aluminum adapter rings P/N 42P6458-1 to prevent reuse.
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Compliance Time
prior to next flight
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Affected Aircraft
VERTOL Models 44A, B, and C Helicopters
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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