Accident Sequence
On February 10, Columbia Pacific Airlines Flight 23, a Beech 99 (registration N199EA), was operating as a regularly scheduled passenger flight from Richland to Seattle, Washington, under 14 CFR 135. The crew arrived at Richland at 1525 on Flight 18 from Seattle. Upon arrival, the aircraft was undergoing inspection to fulfill an Airworthiness Directive and was not available for preflight until 1630, though the flight was scheduled to depart at 1640.
At 1628, the captain received a weather briefing from the Walla Walla Flight Service Station and filed a dispatch release with weight and balance, route, and weather information. Around 1630, the aircraft was fueled and 600 lbs of baggage loaded. At about 1635, the first officer connected the auxiliary power unit, inspected the aircraft, and boarded; the captain boarded shortly after. When the boarding call was made, the captain left to get magazines for passengers and was seen taking his seat as the first passenger boarded.
At 1646, the first officer contacted the Pasco Airport Traffic Control Tower using Flight No. 29, stating they were taxiing and would request an IFR clearance to Seattle via Yakima when airborne. No further calls were received from the flight. The first officer also informed operations on company frequency that they would depart shortly and relay their estimated arrival time when airborne. The aircraft daily flight log shows the aircraft left the ramp at 1645 and took off at 1648.
Witnesses described the liftoff attitude as normal, with liftoff point estimated between 1,173 and 1,486 feet. Immediately after, the aircraft entered a steep climb at an angle of 20° to 45° to 300 to 400 feet above the runway, then appeared to decelerate. The wings rocked or wobbled at the top of the climb, and the aircraft turned or yawed left. The nose dropped, and the aircraft descended at an estimated 45° flightpath angle. Fuel from ruptured tanks caught fire, and the aircraft was consumed by fire within 7 minutes. All 17 occupants were killed.
Probable Cause
The National Transportation Safety Board determined that the probable cause of the accident was the failure or inability of the flightcrew to prevent a rapid pitchup and stall by exerting sufficient push force on the control wheel. The pitchup was induced by the combination of a mistrimmed horizontal stabilizer and a center of gravity near the aircraft's aft limit. The mistrimmed condition resulted from discrepancies in the aircraft's trim system and the flightcrew's probable preoccupation with making a timely departure. Additionally, a malfunctioning stabilizer trim actuator detracted from the flightcrew's efforts to prevent the stall. Contributing to the accident were inadequate flightcrew training, inadequate trim warning system check procedures, inadequate maintenance procedures, and ineffective FAA surveillance.