Soft ice ingested in engine led to RCMP crash
May 28, 2014, Gatineau, Que. - In its investigation report (A12P0008) released today, the Transportation Safety Board of Canada (TSB) determined that the ingestion of soft ice into the engine led to a complete loss of power and the crash after takeoff of a Royal Canadian Mounted Police (RCMP) helicopter near Cultus Lake, B.C. The pilot was fatally injured.
On 17 January 2012, the RCMP helicopter, a Eurocopter AS 350 B3 involved in a training exercise, landed near Cultus Lake, B.C.; subsequently, a heavy snowfall began. The helicopter departed following the snowfall but soon after takeoff, a muffled bang, and the sounds of the engine and rotor diminishing rapidly were heard. The aircraft descended almost vertically, colliding with terrain in a nose-down, right-side down attitude.
The investigation found the protective engine covers had not been installed when the helicopter was parked during the heavy snowfall, and that the air intake system was not cleaned and dried prior to engine start. After the helicopter was started and running at low power, soft ice had built up inside the air intake; and during take-off at high power, the ice broke free and was ingested into the engine compressor which led to a complete engine power loss. This caused the rapid loss of the main rotor speed, an extremely high rate of descent, and the impact with terrain that was not survivable.
Since the accident, Eurocopter, the RCMP and Transport Canada (TC) have reminded pilots of the need to ensure the engine air intake system is clean prior to takeoff. However, the investigation concluded that the full range of recommended preventative measures cannot easily be accomplished in field operations and this presents a risk. Given this risk, TC has undertaken to review the engine inlet design of these helicopters.
In the meantime, there are over 500 Eurocopter AS 350 and EC 130 helicopters being operated by 132 operators in Canada. The investigation found these helicopters are susceptible to ice formation in cold weather operations, and the Board is concerned that in certain conditions, these helicopters may be at increased risk of engine flame-out shortly after takeoff.