Also very unusual - Luckily no injuries....
The pilot of the helicopter registered C-FZQF was performing run-ups on the ground to carry out the balancing of the anti-torque rotor, as part of a 100-hour inspection. The main transmission had also just been replaced by a transmission that had been repaired following an incident where the blades had touched an obstacle. On the third try, the pilot heard an unusual noise and cut the gas.
The main rotor had detached from the strut and, after having climbed to 150 ft, it fell about 100 ft away.
ASN Aircraft accident 08-MAR-2004 Schweizer 269C1 C-FZQF