Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for Airbus Helicopters Model BO-105A, BO-105C, and BO-105S helicopters. This AD requires inspections to detect oil contamination in the main gearbox (MGB). This AD was prompted by initial findings from an accident investigation of a Model BO-105 helicopter, which indicated deterioration of the MGB caused by a contaminated oil supply. The actions of this AD are intended to detect oil contamination in the MGB, which could result in MGB deterioration, MGB failure, and subsequent loss of control of the helicopter.