Is AD 04-26421 a recurring Airworthiness Directive?

No — AD 04-26421 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 04-26421 apply to?

AD 04-26421 applies to Bombardier, Inc — models DHC-3. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 04-26421

one-time

AD 04-26421 · 2004-12-06 · airframe

Airworthiness Directives; Bombardier, Inc. Model DHC-3 Airplanes

What this AD requires

The FAA adopts a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-3 airplanes modified with A.M. Luton's Supplemental Type Certificate (STC) number SA3777NM. This AD requires you to inspect the wiring for the heating blankets on P<INF>3</INF> and P<INF>Y</INF> pneumatic lines and the push-to-test function lights to ensure that they are wired to the correct schematic; replace the circuit breaker switch as applicable; and replace the flight manual supplement currently in use with Revision G, dated March 28, 2001 (incorporates Revision I of Sheet 1 of Drawing 20075, "Electrical System Schematic," dated October 10, 2000). This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Canada. We are issuing this AD to detect and correct wiring installed in accordance with an incorrect drawing, which shows the pneumatic heating blankets to the P<INF>3</INF> and P<INF>Y</INF> pneumatic lines wired in series with the indicator lights, rather than parallel. This can result in reduced current for the heating blankets and loss of pneumatic line heating, which can lead to loss of engine power or reverse propeller overspeed governing protection and ultimately loss of control of the airplane.

Which aircraft AD 04-26421 applies to

MakesBombardier, Inc

ModelsDHC-3

certain

Whether AD 04-26421 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.

How AD compliance is recorded

A valid compliance record (14 CFR 43.9) states:

Method of compliance — The specific action taken (inspected, replaced, modified) and to what revision.

Date — When the work was done.

Aircraft time — Total time in service / tach at compliance — how recurring next-due is computed.

Signature & certificate — The A&P/IA who returned it to service, with certificate number.

Is AD 04-26421 complied with on your aircraft?

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.