Is AD 2012-21-18 a recurring Airworthiness Directive?

Yes — AD 2012-21-18 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 2012-21-18 apply to?

AD 2012-21-18 applies to Boeing — models MD-90-30, MD-90. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2012-21-18

recurring

Official AD 2012-21-18 · FR doc 2012-26187 · 2012-10-31 · airframe

Airworthiness Directives; The Boeing Company Airplanes

What this AD requires

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model MD-90-30 airplanes. This AD was prompted by reports of fatigue cracks found in Stringer 11 at the outboard flap, inboard drive hinge at Station Xrs=164.000. This AD requires repetitive inspections for cracks in Stringer 11, and a splice repair if necessary; and repetitive post-repair inspections, and repair if necessary. We are issuing this AD to detect and correct such cracking, which could result in the wing structure not supporting the limit load condition, which could lead to loss of the structural integrity of the wing.

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

Which aircraft AD 2012-21-18 applies to

MakesBoeing

ModelsMD-90-30, MD-90

Applies only to airplanes identified in Boeing Alert Service Bulletin MD90-57A030, dated February 14, 2012 (Effectivity).

Whether AD 2012-21-18 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 2012-21-18 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.