The Australian Transport Safety Bureau is advising operators of Robinson R44 helicopters to check their hydraulic boost servos following a fatal accident earlier this year when part of a helicopter's flight controls separated from the hydraulic-boost system.

The R44 was performing circuit operations at Cessnock aerodrome in New South Wales with an instructor, a pilot undergoing a helicopter flight review and a passenger.

The hydraulic system failed following the completion of a sequence involving the simulated failure of the hydraulic-boost system. The pilot lost control of the aircraft as he was trying to reposition it for further examination.

Robinson R44
 © Robinson

The helicopter collided with the runway and the R44 caught fire. The pilot survived the accident but the instructor and passenger died. The safety bureau found that a bolt securing part of the flight-control system had detached, prompting its recommendation to inspect and test the security of the flight-control attachments, paying particular attention to the connections at the top and bottom of the servos. The bureau is continuing its investigation.

Source: Flight International