Is AD 2021-13-18 a recurring Airworthiness Directive?

No — AD 2021-13-18 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 2021-13-18 apply to?

AD 2021-13-18 applies to Boeing — models 737. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2021-13-18

one-time

Official AD 2021-13-18 · FR doc 2021-16174 · 2021-07-30 · airframe

Airworthiness Directives; The Boeing Company Airplanes

What this AD requires

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 737 airplanes powered by LEAP-1B engines. This AD was prompted by reports of inadvertent release of the spring energy of the spring door opening system (SDOS) actuator with a certain part number, causing injury and the potential for injury to maintenance personnel. This AD requires replacing each affected SDOS actuator with a new SDOS actuator, and verifying that new safety markers are installed in the proper locations. The FAA is issuing this AD to address the unsafe condition on these products.

Which aircraft AD 2021-13-18 applies to

MakesBoeing

Models737

Applies only to Model 737 airplanes powered by LEAP-1B engines.

Whether AD 2021-13-18 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 2021-13-18 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.