Summary
We propose to supersede Airworthiness Directive (AD) 2008-11- 17, which applies to certain Air Tractor, Inc. Models AT-200, AT-300, AT-400, AT-500, AT-600, and AT-800 series airplanes. AD 2008-11-17 currently requires you to install an overturn skid plate kit or a modification to the overturn skid plate already installed. Since we issued AD 2008-11-17, the manufacturer has notified us that Model AT- 401B airplanes also require a modification to the overturn skid plate. Consequently, this proposed AD would retain the actions of AD 2008-11- 17 and add the requirement to modify the overturn skid plate installed on Model AT-401B airplanes. We are proposing this AD to prevent the front and rear connections of the overturn skid plate to the airplane from breaking, which could allow foreign debris to enter the cockpit during an airplane overturn. This condition, if not corrected, could lead to pilot injury.