Is AD 99-17-09 a recurring Airworthiness Directive?

Yes — AD 99-17-09 requires a repetitive inspection every 100 hours. Next-due depends on the aircraft's time in service.

Which aircraft does AD 99-17-09 apply to?

AD 99-17-09 applies to Allison Engine Company — models AE 2100A, AE 2100C, AE 2100. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 99-17-09

recurring

Official AD 99-17-09 · FR doc 99-21330 · 1999-08-20 · turboprop engine

Airworthiness Directives; Allison Engine Company, Inc AE 2100A and AE 2100C Series Turboprop Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD) that is applicable to Allison Engine Company, Inc AE 2100A and AE 2100C series turboprop engines. This action requires initial and repetitive visual inspections of the propeller gearbox (PGB) and power section (P/ S) strut fittings for notches and cracks, and, if necessary, replacement with serviceable parts. In addition, this action requires removing and replacing strut fittings as well as reworking them to the latest configuration identified by a new part number (P/N). This amendment is prompted by reports of P/S strut fitting notches and cracks. The actions specified in this AD are intended to prevent PGB and P/S strut fitting cracks, which could result in PGB misalignment, in-flight engine shutdown, and possible loss of the propeller.

Repetitive inspection. Re-inspect every 100 hours. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 99-17-09 applies to

MakesAllison Engine Company

ModelsAE 2100A, AE 2100C, AE 2100

Installed on but not limited to SAAB 2000 series and Industri Pesawat Terbang Nusantara (IPTN) N-250 series aircraft; applies to each identified engine regardless of modification, alteration, or repair status.

Whether AD 99-17-09 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 99-17-09 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.