Airworthiness Directives; Slingsby Aviation Limited Models Dart T.51, Dart T.51/17, and Dart T.51/17R Sailplanes

This amendment adopts a new airworthiness directive (AD) that applies to all Slingsby Aviation Limited (Slingsby) Models Dart T.51, Dart T.51/17, and Dart T.51/17R sailplanes that are equipped with aluminum alloy spar booms. This AD requires repetitively inspecting the aluminum alloy spar booms and the wing attach fittings for delamination or corrosion damage, and repairing any delamination or corrosion damage found. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this AD are intended to prevent failure of the spar assembly and adjoining structure caused by delamination or corrosion damage to the aluminum alloy spar booms or the wing attach fittings, which could result in reduced controllability or loss of control of the sailplane.