EASA SIB 2008-62
Grob G103 series sailplanes and powered sailplanes; Flight Controls - Airbrake Control System Bolts - Replacement
Summary
EASA Safety Information Bulletin 2008-62 addresses the replacement of airbrake control system bolts on Grob G103 series sailplanes and powered sailplanes. The bulletin references Luftfahrt-Bundesamt Airworthiness Directives D-2008-231 and D-2008-232, which affect various Grob G103 models including the G103C Twin III SL and G103 Twin Astir series. The issue involves bolt cracking due to excessive torque or irregular adjustment, potentially compromising flight control safety.
What Changed
This bulletin introduces the requirement to remove and replace the airbrake control system bellcrank bolts (part number LN9037-M6x60 or LN9037-M6x62) with new bolts installed using the correct torque of 6.4 Nm. It also mandates inspection of related control parts for damage and verification of airbrake locking forces to ensure proper function. These measures are based on manufacturer service bulletins and German ADs to prevent bolt fatigue failure.
Why It Matters
The bolt cracking issue poses a serious safety risk as it can lead to airbrake and elevator control failure, reducing the controllability of affected Grob sailplanes. Aviation professionals must address this to maintain airworthiness and ensure safe operation. Compliance with these measures helps prevent in-flight control system failures and supports regulatory adherence.
What To Do
Operators and maintenance personnel must replace the specified bolts with new ones using the correct torque, inspect all related airbrake control components for damage, and verify airbrake locking forces on both wings and the cockpit lever. All actions must be completed by 30 September 2008 following the referenced Grob Aerospace service bulletins and Luftfahrt-Bundesamt directives.
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