SEA97FA033 · Beech B36TC

After takeoff, the pilot contacted Flight Watch, while in VFR conditions, & obtained weather information, which included forecast icing conditions and a low ceiling at the destination (Jackson, WY). From about 170 miles southeast of Jackson, the pilot was cleared to proceed via Victor 238. During arrival, he was cleared for a VOR/DME approach to runway 36. Radar data indicated that while en route, the aircraft (acft) did not fly down the center of the airway, but was to the right by a few miles. The controller informed the pilot of this, & he responded that his VOR was 'kind of in and out.' The pilot's last transmission to the controller (before he was cleared for the approach) was that he was picking up moderate rime ice. At the 16 DME arc, the flight did not make a required turn to the west (onto the arc), but continued to parallel the airway. Shortly thereafter, radar contact was lost. Subsequently, the acft impact terrain near the top of a 10,741' peak, located approximately 11 miles southeast of the airport. Minimum altitude for the approach was 12,700' on the arc until passing west of the 165 deg radial, then 11,500' until inbound on the 186 deg radial. Evidence at the accident site indicated that after impact, an avalanche started, then the acft slid downhill about 300' before coming to rest partially buried in snow. Postcrash examination of the wreckage did not reveal evidence of a mechanical failure or malfunction.

Verbatim NTSB analysis and probable cause from the NTSB dataset