Is AD 2021-23-08 a recurring Airworthiness Directive?

Yes — AD 2021-23-08 requires a repetitive inspection every 12 months. Next-due depends on the aircraft's time in service.

Airworthiness Directive 2021-23-08

Q: Which aircraft does AD 2021-23-08 apply to?

AD 2021-23-08 applies to Learjet Inc. — models Learjet 40, Learjet 45, Learjet 70, Learjet 75, Model 45. Serial/part conditions may narrow it to specific aircraft.

recurring

Official AD 2021-23-08 · FR doc 2021-26330 · 2021-12-06 · airframe

Airworthiness Directives; Learjet Inc. Airplanes

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for certain Learjet Inc. (Learjet) Model 45 airplanes. This AD was prompted by reports of corrosion found on the upper surface of the lower center wing mid spar splice plate. This AD requires repetitively inspecting the center wing area for corrosion and deterioration of protective treatments, removing any corrosion, and treating any deteriorated areas. The FAA is issuing this AD to address the unsafe condition on these products.

Repetitive inspection. Re-inspect every 12 months. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 2021-23-08 applies to

MakesLearjet Inc.

ModelsLearjet 40, Learjet 45, Learjet 70, Learjet 75, Model 45

Serial-conditional — narrows to serials 45-002–45-596, 45-2001–45-2146.

Whether AD 2021-23-08 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 2021-23-08 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 →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.