Glasair Aviation Usa Llc SPORTSMAN GS-2 N535SP accident near Castle Rock, Colorado

Probable cause

The pilot’s improper decision to continue flight into known icing conditions, which adversely affected the airplane’s performance and resulted in a loss of airplane control.

NTSB analysis

A review of air traffic control (ATC) recordings indicated that, after the airplane crossed over the mountains, the pilot checked in with the Denver terminal radar approach controller and expressed concern about the weather at her destination airport. After receiving weather for a closer airport, which included visibility 1.5 miles in mist with a 400-foot overcast ceiling, the pilot changed her destination to that airport. About 3 minutes later, the pilot asked the controller if other pilots had reported icing during descent, and the controller responded that other pilots had reported icing in cloud tops about 9,000 feet mean sea level (msl). The pilot advised that she wanted to change back to her original destination, and, shortly later, the controller cleared the approach. About 20 minutes later, the pilot advised the controller that the airplane was "picking up rime ice," and, about 3 minutes later, she again asked for clearance to the intermediate airport; the controller cleared that approach. During the approach, the controller issued three low altitude alerts because the airplane was not maintaining the assigned altitudes, and he provided the pilot with the weather information for the destination airport, which included visibility 2 miles in mist, 400 feet overcast, and temperature and dew point below freezing at -1° C. The pilot reported being established on the approach about 3 miles from the final approach fix shortly before the controller issued the third low altitude alert. After this alert, the pilot responded that the airplane was climbing and maintaining altitude and was established on the approach. Shortly later, the controller asked the pilot to indicate the airplane's altitude, but the pilot did not respond. Radar track data indicated that the airplane was about 6,800 feet msl before radar and radio contact were lost. The airplane subsequently descended and impacted terrain. The airplane likely accumulated ice when the pilot continued flight into known icing conditions, which adversely affected its performance and resulted in a loss of airplane control. ATC services were adequate, and no deficiencies were noted.

Text from the NTSB. Open the NTSB docket for CEN14FA032 for the full record.