Is AD 64-20-01 a recurring Airworthiness Directive?

No — AD 64-20-01 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 64-20-01 apply to?

AD 64-20-01 applies to Hartzell — models HC-E2YL-2B, HC-C2YK-1. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 64-20-01

one-time

AD 64-20-01 · 1964-01-01 · propeller

Airworthiness Directives; propellers which resulted in severe roughness or vibration in flight. To correct this condition, accomplish the following: (a) Ins

Which aircraft AD 64-20-01 applies to

MakesHartzell

ModelsHC-E2YL-2B, HC-C2YK-1

Failure of plastic pitch change blocks in Hartzell HC-E2YL-2B and HC-C2YK-1 propellers resulted in severe roughness or vibration in flight; inspect propeller blades for pitch change movement and replace as necessary.

Whether AD 64-20-01 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 64-20-01 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.