AD 98-24-20 63 FR 65048

This amendment adopts a new airworthiness directive (AD) that applies to certain Grob Luft-und Raumfahrt (Grob) Models G 109 and G 109B sailplanes. This AD requires inspecting the radius of the landing gear retaining bars, installing additional supportive parts, and replacing the retaining bars if the retaining bars' chamfer radius is less than 3.0 millimeters (mm). This AD also requires inspecting the landing gear legs for cracks and proper thickness, and either polishing out the cracks or replacing the landing gear legs with parts of improved design depending on the crack length. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany. The actions specified by this AD are intended to detect and correct fatigue cracking of the landing gear legs, which could result in landing gear failure with consequent loss of control of the sailplane during landing operations.