Summary
We propose to supersede Airworthiness Directive (AD) 84-09-05, which applies to certain GROB-WERKE GMBH & CO KG (previously identified as BURKHART-GROB FLUGZEUGBAU INDUSTRIESTRABE) Model G102 ASTIR CS sailplanes. AD 84-09-05 requires you to install a modified spherical locking bolt and nut in the forward horizontal stabilizer connection to the vertical stabilizer and install new locking pins in the aft connecting plate for the horizontal stabilizer. Since we issued AD 84- 09-05, fatigue cracks were found in the modified spherical locking bolt. Consequently, this proposed AD would require you to replace the modified spherical locking bolt, the retaining pins (collar bolts), and associated hardware; add a life limit on the spherical locking bolt and the retaining pins; and repetitively inspect the front and rear horizontal stabilizer attachment. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany.We are proposing this AD to prevent cracks in the spherical locking bolt, which could result in failure of the horizontal stabilizer connection. This failure could lead to loss of control.