Summary
We propose to supersede Airworthiness Directive (AD) 2006-08- 09, which applies to all Air Tractor, Inc. (Air Tractor) Models AT-802 and AT-802A airplanes. AD 2006-08-09 currently requires you to repetitively inspect (using the eddy current method) the two outboard fastener holes in both of the wing main spar lower caps at the center splice joint for cracks and repair or replace any cracked spar cap. Since we issued AD 2006-08-09, we have determined we need to clarify the applicability of Models AT-802 and AT-802A airplanes affected serial number (SN) ranges. Additionally, we propose to add an option of modifying the wing main spar lower caps to extend the safe life limit on the affected airplanes. Consequently, this proposed AD would keep the actions of AD 2006-08-09, clarify the applicability of Models AT- 802 and AT-802A affected SN ranges, and add a modification option to extend the safe life limit. We are proposing this AD to detect and correct cracks in the wing main spar lower cap at the center splice joint, which could result in failure of the spar cap and lead to wing separation and loss of control of the airplane.