AD 2021-23-02
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-8-401 and - 402 | Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes |
Unsafe Condition
insufficient separation between the advanced pneumatic detector (APD) sensing line and surrounding components, which could lead to a hydraulic leak, loss of hydraulic systems and loss of fire detection in the main landing gear (MLG) primary zone should prolonged contact occur.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Do a detailed visual inspection for chafing and proper clearance of the left- and right-hand MLG primary zone APD sensing lines, the hydraulic tube assemblies, and the surrounding structure, and doing all applicable corrective actions. Corrective actions include repair and replacement of the APD sensing line and the hydraulic tube assembly.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 48 months or 8,000 flight hours, whichever occurs first after the effective date of this AD
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, certificated in any category, serial numbers 4001 and 4003 through 4614 inclusive.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.