NTSB Factual Report

On June 15, 2009, about 1652 mountain daylight time (mdt), a Beech B100 (King Air) airplane, N4490M, operated by Air Methods Corporation, encountered clear-air-turbulence while descending through 7,000 feet mean sea level (msl) en route to Rapid City Regional Airport (KRAP), Rapid City, South Dakota. Visual meteorological conditions prevailed during the flight. The air-ambulance flight was conducted in accordance with 14 Code of Federal Regulations (CFR) Part 135 while on an instrument flight plan. The patient was seriously injured as result of the turbulence encounter. The 4 flight crew members sustained minor injuries. The flight departed Gordon Municipal Airport (KGRN), Gordon, Nebraska, at 1619 mdt.

Before being loaded onto the airplane, the patient was lying on an ambulance gurney and was already secured to a flexible lift system at the waist and legs. The use of the flexible lift system allowed the easy transfer from the ambulance gurney to the aircraft-mounted stretcher assembly. The lift system comprised of a plasticized sheet and full body length foam pad. The patient was secured to this lift system using the available waist and leg straps.

For patient transfers, flight crewmembers grab the edges of the flexible lift system to lift and transfer the patient from the ambulance gurney to the airplane’s stretcher. The airplane’s stretcher also incorporated a full body pad, and its support frame articulated at the waist to elevate the patient’s upper body from a supine position into an inclined position. The airplane’s stretcher had leg, waist, and left and right over-the-shoulder straps. The over-the-shoulder straps combined at the waist strap buckle assembly.

The patient, who was already restrained in the flexible lift system by waist and leg straps, was then restrained to the airplane’s stretcher using the stretcher’s available waist and leg straps. The full body pad and plasticized sheet of the flexible lift system completely covered and prevented the use of the over-the-shoulder restraints installed on the airplane’s stretcher.

During the flight, the stretcher’s back support was raised into an inclined position for added patient comfort. During cruise descent, the airplane encountered clear-air-turbulence, during which the patient’s upper-torso fell off the stretcher. After the turbulence encounter, the patient’s unrestrained head, neck, and upper-torso were laying off the stretcher in the center aisle. His restrained lower body remained attached to the stretcher which was elevated off the cabin floor. The cabin flight crewmembers stabilized the patient’s neck before repositioning him back onto the stretcher. The airplane then made an uneventful landing at its intended destination. The patient suffered a fracture of the C3 cervical vertebra during the turbulence encounter.

After the accident, the aeromedical transport company discontinued the use of the flexible patient lift system model utilized during the accident flight and required flight crewmembers to only use lift systems that allowed the use of the aircraft stretcher’s available over-the-shoulder restraints.

NTSB Probable Cause

The flight crewmembers’ failure to secure the patient using the available over-the-shoulder restraints and the encounter with clear-air turbulence during cruise descent.