Is AD 2009-24-21 a recurring Airworthiness Directive?

Yes — AD 2009-24-21 requires a repetitive inspection every 18 months. Next-due depends on the aircraft's time in service.

Which aircraft does AD 2009-24-21 apply to?

AD 2009-24-21 applies to Mcdonnell Douglas — models DC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2009-24-21

recurring

Official AD 2009-24-21 · FR doc E9-28564 · 2009-12-04 · airframe

Airworthiness Directives; McDonnell Douglas Model DC-9-14, DC-9-15, and DC-9-15F Airplanes; and McDonnell Douglas Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes

What this AD requires

The FAA is superseding an existing airworthiness directive (AD) that applies to all McDonnell Douglas Model DC-9-14, DC-9-15, and DC-9-15F airplanes; and McDonnell Douglas Model DC-9-20, DC-9-30, DC-9- 40, and DC-9-50 series airplanes. That AD currently requires repetitive inspections for cracks of the main landing gear (MLG) shock strut cylinder, and related investigative and corrective actions if necessary. This AD adds more work on airplanes that have main landing gear shock struts with certain identified part numbers. This AD results from two reports of a collapsed MLG and a report of cracks in two MLG cylinders. We are issuing this AD to detect and correct fatigue cracks in the shock strut cylinder of the MLG, which could result in a collapsed MLG during takeoff or landing, and possible reduced structural integrity of the airplane.

Repetitive inspection. Re-inspect every 18 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 2009-24-21 applies to

MakesMcdonnell Douglas

ModelsDC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-32F (C-9A, C-9B), DC-9-33F, DC-9-34, DC-9-34F, DC-9-41, DC-9-51, DC-9

Whether AD 2009-24-21 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 2009-24-21 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.