NYC08LA176 · Desalvatore Al Lancair IV-P

The pilot departed under visual flight rules for a 1,016 nautical-mile cross-country flight in the single engine, high performance, amateur-built airplane. About 2.5 hours into the flight, the pilot requested and was given, and instrument flight rules (IFR) clearance, and subsequently descended from 17,500 feet to 17,000 feet. About 4 minutes later, the pilot queried air traffic control (ATC) regarding the weather conditions ahead, and was advised of another airplane reporting light rime icing between 15,000 and 12,000 feet. Another aircraft further ahead did not report any ice at 11,000 feet. About 12 minutes after requesting the IFR clearance, the pilot requested to descend due to icing conditions. ATC cleared the airplane to descend to 15,000 feet, and advised that if further descent was required the airplane would have to be vectored around climbing traffic. The accident airplane was lost from radar shortly thereafter. The conflicting, climbing traffic pointed out by ATC was a business jet, and the crew, which observed the accident airplane on their collision avoidance system, reported no icing while flying at 14,000 feet. Review of weather radar data and satellite imagery revealed the presence of relatively colder convective cloud tops as the airplane progressed along its flight path, and implied positive vertical velocities and weak embedded high-altitude convection in the area. Level 1 weather radar returns and recorded temperatures aloft of -3 to -7 degrees Celsius indicated that super-cooled large water droplets were most likely present in the area. The accident airplane most likely encountered moderate to severe clear or mixed icing while descending out of 17,000 feet. A review of flight service station data revealed the pilot did not contact any flight service stations or utilize the Direct User Access Terminal System (DUATS) to obtain a weather briefing, or file a flight plan, prior to commencing the flight, nor did the pilot contact any flight service stations while en route.

Verbatim NTSB analysis and probable cause from the NTSB dataset