Airworthiness Directive E8-18683
one-timeAirworthiness Directives; Bombardier Model DHC-8-400 Series Airplanes
What this AD requires
The FAA is superseding an existing airworthiness directive (AD) that applies to certain Bombardier Model DHC-8-400 series airplanes. The existing AD currently requires revising the Limitations section of the airplane flight manual (AFM) to include procedures for pulling the "HYD PWR XFER" circuit breaker in the event of the loss of all hydraulic fluid in the No. 1 or No. 2 hydraulic system. This AD requires a revision to the AFM to include additional procedures for ensuring that the "PTU CNTRL" switch is Normal, the "PTU CNTRL ON" advisory light is out, and the "HYD PWR XFER" circuit breaker is pulled in the event of the illumination of the "<greek-i>2 HYD ISO VALVE" caution light. This AD resulted from low No. 2 hydraulic pressure in-flight, which caused the power transfer unit to overspeed, and the fluid flow within the No. 1 hydraulic system to increase. We are issuing this AD to prevent possible loss of both the No. 1 and No. 2 hydraulic systems, resulting in the potential loss of several functions essential for safe flight and landing of the airplane.
Which aircraft AD E8-18683 applies to
Serial number 4003 and subsequent (open-ended range).
Whether AD E8-18683 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
Supersession
Supersedes AD 2007-12-03.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.