Flight Preparation and Weather Information
The captain reported obtaining weather briefings prior to and during the flight. The briefings did not include any NOTAMs indicating a contaminated runway at the destination airport. The captain also obtained a report from the local fixed base operator that a Learjet had landed earlier and reported the runway as being okay.
Landing Approach
Upon arrival, the tower was closed, so the flight crew performed a low pass over the airport to inspect the runways. Based on the runway and wind conditions, they decided to land on runway 08L.
Accident Sequence
The captain stated the landing was normal, with initial deceleration using normal braking. As the airplane encountered snow and ice patches, the captain elected to deploy the thrust reversers. Upon deployment, the airplane began to yaw to the left, and differential braking failed to realign the airplane with the runway. The airplane departed the left side of the runway, rotated counter-clockwise, and came to rest on a southwesterly heading.
A witness on the airport reported: "I watched them touch down. I heard the [thrust] reversers go on and then off, and then on again. As they came back on for the second time, that's when the plane started making full circles on the runway. This happened two, maybe three times before going off the side of the runway."
Post-Accident Examination
During the excursion, the right main landing gear collapsed, causing substantial damage to the right wing, right main landing gear, and aft pressure bulkhead. At the accident site, the right engine thrust reverser was partially deployed, while the left engine thrust reverser was fully deployed with the blocker doors extended. An examination of the airplane revealed a stuck solenoid on the right engine thrust reverser. No other system anomalies were found.
Weather and Runway Conditions
Approximately 33 minutes before the accident, the pilot requested weather information from Denver Air Route Traffic Control Center. The center reported winds calm, visibility 6 miles with light mist, 3,000 feet overcast, temperature 0°C, dew point -1°C, altimeter 30.20, and at least half an inch of slush on all surfaces. The pilot acknowledged this information. The NOTAM log for the airport showed that at 2115, a NOTAM was issued stating "1/2 inch wet snow all surfaces." The airport operations manager reported that at the time of the accident, the runway surface was covered with 3/4 inch of wet snow. The airport operates 24 hours a day, 7 days a week, but operations support digresses to fire coverage only after 2300.