Airworthiness Directives; Raytheon Aircraft Company Beech Models C90A, B200, B300, and 1900D Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to all Raytheon Aircraft Company (Raytheon) Beech Models C90A, B200, B300, and 1900D airplanes. This AD requires replacing the landing gear hand pump for airplanes that had a pump within a certain serial number range installed at manufacture; and prohibits the future installation of any of these pumps on all of the affected airplanes. This AD is the result of information from the manufacturer of improper machining of the pump housing on certain landing gear emergency hand pumps on the affected airplanes. This resulted in an insufficient groove depth to retain a snap ring, which retains the check valve in its proper position within the housing. The actions specified in this AD are intended to detect any improperly machined landing gear emergency hand pumps, which, if not removed from service, could result in the inability to properly lower and lock the landing gear in the event of failure of the primary retraction/extension system.