Robinson R22 Beta — Service Bulletins

This document is an AAIB Bulletin detailing an incident involving the Robinson R22 Beta helicopter, registration G-BOAM. It outlines the circumstances of a flight incident that occurred on May 26, 1998, during a training exercise. The bulletin provides a thorough investigation into the mechanical failure of the sprag clutch assembly, which was identified as the cause of the incident. The document also includes findings from engineering inspections and subsequent actions taken by the helicopter manufacturer, including the issuance of Service Bulletins for affected sprag clutch assemblies. This bulletin serves as a critical reference for operators and maintenance personnel of the Robinson R22 Beta, emphasizing the importance of addressing potential mechanical failures to ensure flight safety.

• Incident occurred on May 26, 1998, during a training flight with the Robinson R22 Beta.
• The sprag clutch assembly was identified as the source of mechanical failure.
• The sprag clutch had accumulated 320 flight hours since its last overhaul.
• Metallurgical examination revealed failures due to medium cycle tension fatigue and wear.
• Service Bulletins SB-85 and SB-32 were issued for the replacement of affected sprag clutches.