L2012-07 Helicopter accident on a sawing flight in Juuka on 16 May 2012

The helicopter crashed into the ground on a branch sawing flight to clear a power line on 16 May 2012 at about 19:56 Finnish time. The accident occurred in a boggy area below the west side of Rasivaara hill near the village of Juuka.

After sawing for about 20 minutes, the pilot started to move to a new support base to examine the conditions along the next line section to be sawed. He was alone in the aircraft. The pilot flew at a speed of about 20 knots and at a height of approximately 200 feet above the ground, following the power line. On the western slope of Rasivaara hill the speed increased until the pilot slowed it down by pulling the helicopter nose up, and the speed and height started to decrease. There were two feeder lines that diverted from the main power line at the hillside. After the flight had progressed to the edge of the boggy area, the pilot got a feeling that the helicopter did not have enough power. He did not notice any other abnormalities in the helicopter, and instead of jettisoning the branch saw, decided to put it down on the ground. After the saw hit the ground, the helicopter continued to sink, impacted the ground uncontrollably and was completely destroyed. The pilot was slightly injured. There was no fire.

The probable cause of the accident was that the pilot focused too much attention on the sawing conditions along the next power line section and to the saw hanging under the helicopter. This reduced his situational awareness and led to an incorrect assessment of the prevailing flight conditions, as a result of which he used a control technique not suitable for the situation.

Based on the investigation, two safety recommendations were issued to the Finnish Transport Safety Agency. The recommendations concern training requirements for pilots who fly sawing flights, as well as the determination and verification of take-off mass or power reserve for helicopters used for sawing flights.

Additional information
Chief Air Safety Investigator
Ismo Aaltonen
tel. +358 2951 50703

L2012-07 Report (pdf, 4.68 Mt)