Final Report: JetRanger's main drive shaft failed

 - September 20, 2006, 6:56 AM

Bell 206B JetRanger, Cleveland, Ohio, June 25, 2005–A failure of the main drive shaft for undetermined reasons, the NTSB concluded, caused the total loss of engine power in the Bell 206B JetRanger. A factor in the accident was the pilot’s improper flare.

After hearing a loud bang while hovering at 5,000 feet, the JetRanger’s pilot said, the helicopter yawed to the right and pitched nose down. He regained control at about 1,500 feet and performed an autorotation to Burke Lakefront Airport, where he landed hard, with the main rotor hitting the tailboom, which broke off the helicopter. The isolation mount had separated from the transmission and the main drive shaft separated. Investigators determined the failures were consistent with an excessive angular displacement between the rotational axis of the drive shaft and couplings. Damage was found to the structure around the main drive shaft and there was grease spray consistent with rotation before failure. Small pieces of metal and metallic dust were found at the front of the transmission deck.

The pilot, the sole occupant, was not injured.