Is AD 63-21-04 a recurring Airworthiness Directive?

No — AD 63-21-04 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 63-21-04 apply to?

AD 63-21-04 applies to Lockheed, Spartan — models L-18, PV-1. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 63-21-04

one-time

AD 63-21-04 · 1963-01-01 · appliance

Airworthiness Directives; -04 LOCKHEED: Amdt. 625 Part 507 Federal Register October 2, 1963. Applies to All Models L-18 and PV-1 Airplanes Equipped With Spa

Which aircraft AD 63-21-04 applies to

MakesLockheed Spartan

ModelsL-18, PV-1

Lockheed Model L-18 and PV-1 airplanes equipped with Spartan electrically actuated elevator trim tabs, to prevent runaway trim tab actuator operation; Model 18 airplanes with Spartan trim tab require installation per STC SA2-183.

Whether AD 63-21-04 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 63-21-04 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.