Overview
On 1 September 2010, at 1606 Eastern Daylight Time, a Eurocopter AS350 B-2 (registration C-GHVD, serial number 1236) operated by Canadian Helicopters Limited was involved in an accident approximately 12 nautical miles northwest of Chibougamau, Quebec. The aircraft came to rest on its left side after colliding with trees during a precautionary landing. There was no post-crash fire.
History of the Flight
The helicopter had departed a work site 85 nautical miles northwest of Chibougamau at 1529 on a visual flight rules flight to the Hydro-Québec helicopter base. The pilot and three passengers were on board. Earlier that day, between 1430 and 1500, heavy rain associated with a cold front had passed through the work site. After the rain stopped and the sky cleared, the pilot took off.
During the return flight, weather deteriorated. Approximately 20 nautical miles from the destination, visibility decreased to about 1 mile in moderate rain. The pilot deviated south with the intention to land in a blueberry field beyond a gravel road. However, as the helicopter approached the gravel road on which the pilot decided to land, visibility continued to worsen.
Final Approach and Collision
On the final approach, at approximately 70 feet above ground level and low airspeed over trees, the pilot lost all visual reference with the terrain due to heavy rain. While in a hover over the trees, the helicopter descended without the pilot realizing it. It struck the trees and then the ground, coming to rest on its left side about 75 feet from the road.
Wreckage and Injuries
The descent was vertical with little forward speed. The main rotor blades shattered and separated. One blade wrapped around the mast as the engine continued to drive the transmission. The engine showed signs of foreign object damage from ingested dirt and vegetation.
The cabin remained relatively intact, but the front nose area and windscreen collided with trees, shattering the windscreen and nose cone windows. The rear floor buckled near the rear right outboard seat. The tail boom and tail rotor separated as one piece at the tail boom junction frame.
All seats remained anchored. The pilot and front left passenger wore four-point inertia reel safety belts. The pilot sustained serious facial injuries despite wearing a helmet. The front passenger suffered a fracture to the left shoulder. The two rear passengers, wearing three-point belts and shoulder harnesses, sustained minor injuries. Occupants exited through the shattered windscreen.
Emergency Response
The KANNAD 406 MHz emergency locator transmitter activated on impact and was later switched to the ON position by the pilot. Passengers accessed survival equipment from the right side cargo compartment. A passenger called the Canadian Helicopters base via satellite phone at 1615. A company helicopter arrived within 40 minutes. Meanwhile, passengers flagged down a truck driver who stayed until ambulances arrived at 1705. All occupants were transported to hospital.
Weather Information
The pilot had been aware of a cold front forecast for approximately 1600, as advised by the base manager at 1101. The graphical area forecast issued at 0131 indicated a possibility of thunderstorms for the Chibougamau area in the afternoon, with isolated heavy thunderstorms and reduced visibility. However, the valid terminal aerodrome forecast for Chibougamau Airport did not mention thunderstorms. Weather radar coverage did not extend to the area, so thunderstorms within 40 statute miles of the airport were not visible on radar.
The helicopter was not equipped with windshield wipers, an option not commonly installed on lightweight helicopters due to potential scratching of polycarbonate windshields. Heavy precipitation during final approach would have accumulated on the windshield, restricting visibility.