Is AD 73-13-08 a recurring Airworthiness Directive?

No — AD 73-13-08 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 73-13-08 apply to?

AD 73-13-08 applies to Cessna. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 73-13-08

one-time

AD 73-13-08 · 1973-01-01 · reciprocating engine

Airworthiness Directives; engine oil, within the next 25 hours' time in service after the effective date of this AD, install a check valve in the crankcase

Which aircraft AD 73-13-08 applies to

MakesCessna

Within the next 25 hours time in service after the effective date, install a check valve in the crankcase breather oil separator line per Cessna Service Letter No. ME73-10, dated May 18, 1973, or a later FAA-approved revision or equivalent modification.

Whether AD 73-13-08 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 73-13-08 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.