Is AD 2006-08-08 a recurring Airworthiness Directive?

Yes — AD 2006-08-08 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 2006-08-08 apply to?

AD 2006-08-08 applies to Air Tractor — models AT-400, AT-401, AT-401B, AT-402, AT-402A, AT-402B. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 2006-08-08

recurring

Official AD 2006-08-08 · FR doc E9-7068 · 2009-03-31 · airframe

Airworthiness Directives; Air Tractor, Inc. Models AT-400, AT-401, AT-401B, AT-402, AT-402A, and AT-402B Airplanes

What this AD requires

We are adopting a new airworthiness directive (AD) to revise AD 2006-08-08, which applies to certain Air Tractor, Inc. (Air Tractor) Models AT-400, AT-401, AT-401B, AT-402, AT-402A, and AT-402B airplanes. AD 2006-08-08 currently requires you to repetitively eddy current inspect the wing lower spar cap in order to reach the safe life and, for certain Models AT-402A and AT-402B airplanes and those that incorporate or have incorporated Marburger Enterprises, Inc. (Marburger) winglets, lowers the safe life for the wing lower spar cap. Since we issued AD 2006-08-08, we have received information to update inspection intervals for the Models AT-401B, AT-402A, and AT-402B airplanes based on a revised damage tolerance analysis. Consequently, this AD would not only retain the actions of AD 2006-08-08, but would reduce the number of repetitive inspections for all affected Model AT- 401B airplanes and certain Models AT-402A and AT-402B airplanes. We are issuing this AD to prevent fatigue cracks from occurring in the wing lower spar cap before the originally established safe life is reached. Fatigue cracks in the wing lower spar cap, if not detected and corrected, could result in wing separation and loss of control of the airplane.

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 2006-08-08 applies to

MakesAir Tractor

ModelsAT-400, AT-401, AT-401B, AT-402, AT-402A, AT-402B

Serial-conditional — narrows to serials 0416–?, 0662–0951, 0694–0951, 0738–0951, 0952–1020, 0966–1020, 1015–1182, 1021–1182.

Part-conditional — 21058-1, 21058-2.

Establishes wing lower spar cap safe life (hours TIS) that varies by model/serial number and by whether Marburger winglets (STC SA00490LA) are or have been incorporated. Airplanes modified with replacement lower spar caps P/N 21058-1 and P/N 21058-2 get a 9,800-hour safe life and are not eligible for Marburger winglet installation; airplanes with both the replacement spar caps and winglets installed must have the winglets removed and a new safe life obtained from the FAA.

Whether AD 2006-08-08 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 2006-08-08 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.