Airworthiness Directive 90-23-17
one-timeAD 90-23-17 · 1990-01-01 · airframe
Airworthiness Directives; Siddeley Dynamics Air Conditioning System and Rolls Royce Viper Engines, certified in any category. Compliance: Required as indica
Which aircraft AD 90-23-17 applies to
MakesSiddeley Dynamics Air Conditioning System And Rolls Royce Viper
ModelsDH.125-1A, 125-1A
Whether AD 90-23-17 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 90-23-17 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 →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.