AD 2023-05-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bombardier | Various | Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes |
| aircraft | Bombardier | Various | Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes |
| aircraft | de Havilland | Aircraft of Canada Limited Model DHC-8-400 | Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes |
Unsafe Condition
FPU pressure switch failures resulting in flap inoperative events due to deformation of the FPU pressure switch internal mechanism due to hydraulic pressure spikes.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replacing the FPU pressure switch or the FPU, or replacing the FPU pressure switch within the FPU with a new pressure switch and re-identifying the FPU, and accomplishing an operational test of the wing flaps.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 50 flight hours
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes, serial numbers 4001 and 4003 through 4633 inclusive.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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