The air ambulance that crashed while attempting to land in Rawlins, Wyo., on Jan. 11 had up to 1 1/2 inches of clear ice coating de-icing boots on the front of both wings, according to a National Transportation Safety Board report.
The accident killed pilot Tim Benway and two flight nurses. The plane’s fourth occupant, a flight paramedic, was severely injured.
The Yampa Valley Air Ambulance flight, operated by Mountain Flight Service Inc., originated in Steamboat Springs and was heading to Rawlins to pick up a patient for a flight to Casper.
The NTSB report does not list a probable cause of the accident but says investigators who examined the wreckage found coatings of clear ice on a propeller blade and the leading-edge surface of the vertical stabilizer, or tail, as well as the leading edges of the wings.
A buildup of ice on airplane surfaces can affect a pilot’s ability to control a plane. De-icing boots are designed to shed ice by using air bled from the engines to expand the rubber boot and push off the ice.
The NTSB report makes no mention of whether the de-icing boots were operating properly during the flight but said that after the wreckage was removed to a hangar in Greeley, the boots worked normally during a test.
The report said that before the flight departed Steamboat, Benway got a briefing about weather conditions in the Rawlins area and was told there was “light to moderate snow shower activity.”
According to the NTSB report, “The briefer said, ‘Mountain terrain obscuration, icing and turbulence.’ The conversation ended after the pilot responded, ‘All of that fun stuff.”‘
The twin-engine Beech E-90 King Air turboprop crashed at 9:45 p.m. just below the crest of a 7,269-foot ridge about 2.5 miles northeast of the Rawlins airport while the plane was on its final approach to runway 22, the accident report said.
The accident also killed air-ambulance director and flight nurse Dave Linner, 36, and nurse Jennifer Wells, 30. It took rescuers about four hours to find the wreckage and the lone survivor of the crash, paramedic Tim Baldwin, 35. Baldwin suffered head injuries and numerous broken bones and spent about two weeks in the hospital.
Staff writer Jeffrey Leib can be reached at 303-820-1645 or jleib@denverpost.com.
