Is AD 99-6980 a recurring Airworthiness Directive?

Yes — AD 99-6980 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 99-6980 apply to?

AD 99-6980 applies to Mcdonnell Douglas — models C-9, MD-88. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 99-6980

recurring

AD 99-6980 · 1999-03-23 · airframe

Airworthiness Directives; McDonnell Douglas Model DC-9 and DC-9- 80 Series Airplanes, Model MD-88 Airplanes, and C-9 (Military) Series Airplanes

What this AD requires

This amendment corrects information in an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9 and DC-9-80 series airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes, that currently requires repetitive high frequency eddy current inspections of certain areas of the fuselage to detect cracks of the skin and/or longeron, and various follow-on actions. That AD also requires installation of a preventative modification, which terminates the repetitive inspections. The actions specified in that AD are intended to prevent fatigue cracks, which could result in loss of the structural integrity of the fuselage and, consequently, lead to rapid depressurization of the airplane. This amendment corrects the requirements of the current AD by indicating the specific area in which the subject inspection must be conducted. This amendment is prompted by communication received from the manufacturer that the current requirements of the AD are different than the service information referenced as the appropriate service information in the current AD.

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 99-6980 applies to

MakesMcdonnell Douglas

ModelsC-9, MD-88

certain

Whether AD 99-6980 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 99-6980 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.