Summary
We propose to supersede Airworthiness Directive (AD) 2006-24- 11, which applies to certain Hawker Beechcraft Corporation (Hawker) (Type Certificate previously held by Raytheon Aircraft Company) Models 1900, 1900C, and 1900D airplanes. AD 2006-24-11 currently requires you to repetitively inspect the forward, vertical, and aft flanges of both the left and right wing rear spar lower caps for cracks, repair any cracks found, and report the inspection results to the manufacturer. Since we issued AD 2006-24-11, the manufacturer has developed a modification kit to install on the wing rear spar lower caps that would terminate the 200-hour repetitive inspection required in AD 2006-24-11. Consequently, this proposed AD would require installing the new modification kits on the wing rear spar lower caps and would terminate the repetitive inspections required in AD 2006-24-11 when the kits are installed. We are proposing this AD to prevent fatigue cracks in the wing rear spar lower caps, which could result in fatigue failure of the wing rear spar lower caps. A rear spar failure could result in complete wing failure and the wing separating from the airplane.