Amateur-built VELOCITY XL RG N787SB accident near Santa Fe, New Mexico

Probable cause

The airplane’s inadvertent encounter with unforecasted icing conditions during cruise flight, which resulted in the accumulation of airframe icing, the airplane’s inability to maintain altitude, and a subsequent forced landing on rough terrain.

NTSB analysis

The pilot was conducting a cross-country flight in night, visual meteorological conditions when he inadvertently entered an area of instrument meteorological conditions (IMC) and icing, and the airplane subsequently began accruing ice. The experimental airplane was not equipped for flight in known icing conditions. The pilot reported to an air traffic controller that the airplane had entered IMC and had accumulated icing. The pilot then saw a 1-ft-diameter, gelatinous supercooled water mass on the windshield, and 5 seconds later, the entire windshield became crystalized with ice. Several seconds later, the airplane entered an uncommanded dive. The pilot was able to recover from the dive, but he was unable to maintain altitude and declared an emergency with air traffic control. Subsequently, he conducted a forced landing on rough terrain, which resulted in substantial damage to the fuselage and left elevator.

Ice accumulation was observed on the airframe at the accident site, and several pieces of ice were observed along the wreckage debris path. The observed ice accumulation would have precluded smooth airflow over the wing during the flight and resulted in degraded performance.

Meteorological data indicated that the airplane flew into an area of unforecast icing conditions. It is likely the airplane entered supercooled liquid water clouds, which resulted in a sudden accretion of airframe ice. Supplemental satellite weather data indicated a local potential for icing at the accident site; however, without any corroborating pilot reports of icing, an advisory was not issued for the area around the accident site. The pilot stated that he did not review weather data before departure or while en route; however, even if he had he reviewed weather data, it would not have shown that icing conditions were present or forecast.

Text from the NTSB. Open the NTSB docket for CEN18LA077 for the full record.