NTSB releases final report of Gulfstream mountain crash in California

The NTSB has released the final report on the Gulfstream 695A (N965BC) that crashed into mountainous terrain near San Bernardino, California on April 13, 2024. The report states the pilot had been in a recurrency training program the week before the flight and was returning home after completing the week. The instructor told the NTSB that it was planned for the pilot to depart on that leg of the flight at no later than 6:30 p.m. and would remain west due to weather forecasts. The pilot ended up departing from the Stockton Metro Airport (SCK) 30 minutes after the planned departure time and flew a route east of the terrain that had been discussed and flew east of the discussed terrain, so the aircraft was in severe weather conditions after dark.The 695A encountered turbulence while descending from its cruising altitude. Multiple transmissions were recorded between ATC and the pilot over course corrections, altitudes, icing, and issues with the autopilot. ATC did offer vectors from the arrival procedure, but the pilot declined them. The pilot did accept a lower altitude after reporting that he had accumulated moderate rime ice. The aircraft descended to 7,200 ft above sea level, but when instructed to climb back up to 7,400 ft, it remained at the same altitude for 29 seconds and began a right turn. Its groundspeed slowed from 124 kts to 84 kts. ATC asked the pilot if he was ready to turn back to the left and pilot responded that he was turning. The twin-piston then began a rapid descent and the pilot died in the crash. RELATED STORIES: Pilot reported turbulence, icing conditions before crashing into mountainside North Dakota Representative killed in Beechcraft crash in Minneapolis Undetected corrosion caused Challenger 604 to crash on Florida interstate The NTSB states the aircraft likely experienced heavy icing during the descent, including flying through supercooled liquid droplets. The weather at the time had gusts of wind at a speed of 23 kts with rain. Multiple AIRMETS and SIGMETS were in effect throughout the planned route of flight, and areas of moderate to severe icing were forecast. The pilot used the autopilot system while going through the severe conditions. The NTSB claims that either the autopilot hid the effects of ice on the airframe until it reached its limit and disengaged or it remained on until the 695A exceeded its critical angle of attack and entered a stall, which is consistant with the rapid descent and near-vertical impact. The NTSB also noted that a medical review showed the pilot used a cannabis product and could have been impaired while flying, but it is unknown when he last used it. The probable cause of the accident was determined to be the continued use of the autopilot system in moderate to severe icing conditions, which resulted in an aerodynamic stall.