The National Transportation Safety Board blames ice for the 2013 crash of a medical helicopter in Oklahoma City.
The EagleMed Eurocopter AS350B2 crashed at 5:42 a.m. on February 22, 2013 in the parking lot of St. Ann's Retirement Home near Britton and Rockwell.
The crash killed pilot Mark Montgomery and nurse Chris Denning. Medic Billy Wynne was critically injured but survived. The crew had taken off from Integris Baptist Medical Center on its way to transport a cardiac patient from Watonga back to Oklahoma City.
According to the NTSB's Probable Cause Report on the crash, the cause of the crash was "the loss of engine power due to engine ice ingestion during initial climb after takeoff in dark night light conditions."
The NTSB says two factors contributed to the crash: "the lack of an installed engine air inlet cover while the helicopter was parked outside, exposed to precipitation and freezing temperatures before the accident, and the pilot’s inadequate preflight inspection that failed to detect ice accumulation in the area of the air inlet."
According to the report, the helicopter’s air intake had been modified because the aircraft had been fitted with a different engine. The NTSB said the change made it possible for water or snow to accumulate in the intake which would then become ice. If left undetected, the ice would then be sucked into the engine where it would cause damage and a loss of power.
The NTSB said there was precipitation and temperatures as low as 19 degrees in the 12 hours before the accident while the helicopter was parked outside without an air inlet cover installed.
The NTSB noted that the helicopter’s flight manual instructed pilots to check for ice in the inlet by looking and touching, and that the manufacturer and the FAA had issued warnings about the need to check for ice.
Most of the helipad lights were off at the time the pilot did his preflight inspection, making it difficult for him to detect any ice or snow in the air inlet, the NTSB said.