Is AD 98-12-21 a recurring Airworthiness Directive?

Yes — AD 98-12-21 requires a repetitive inspection every 400 hours. Next-due depends on the aircraft's time in service.

Which aircraft does AD 98-12-21 apply to?

AD 98-12-21 applies to Eurocopter France — models SA-315B, SA-315. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 98-12-21

recurring

Official AD 98-12-21 · FR doc 98-15263 · 1998-06-10 · airframe

Airworthiness Directives; Eurocopter France Model SA. 315B Helicopters

What this AD requires

This amendment adopts a new airworthiness directive (AD), applicable to Eurocopter France Model SA. 315B helicopters that requires an initial and repetitive visual inspections and modification, if necessary, of the horizontal stabilizer spar tube (spar tube). This amendment is prompted by an in-service report of fatigue cracks that initiated from corrosion pits. The actions specified by this AD are intended to prevent fatigue failure of the spar tube, separation and impact of the horizontal stabilizer with the main or tail rotor and subsequent loss of control of the helicopter.

Repetitive inspection. Re-inspect every 400 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 98-12-21 applies to

MakesEurocopter France

ModelsSA-315B, SA-315

Part-conditional — 315A35-10-000-1, 315A35-10-000-2.

Applies only to SA-315B helicopters with horizontal stabilizer P/N 315A35-10-000-1, -2, or higher dash number installed.

Whether AD 98-12-21 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 98-12-21 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.