AD 2006-23-01 71 FR 65719

The FAA adopts a new airworthiness directive (AD) for all Air Tractor, Inc. (Air Tractor) Model AT-602 airplanes. This AD requires you to repetitively inspect (using the eddy current method) the wing center splice joint two outboard fastener holes on both of the wing main spar lower caps for fatigue cracking; repair or replace any wing main spar lower cap where fatigue cracking is found; and report any fatigue cracking found. This AD results from fatigue cracking at the wing center splice joint outboard fastener hole in one of the wing main spar lower caps. We are issuing this AD to detect and correct cracks in the wing main spar lower cap, which could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.