Crash of a Rockwell Grand Commander 690 in Herlong: 2 killed

Date & Time: Dec 31, 1992 at 1536 LT
Operator:
Registration:
N300CP
Flight Phase:
Flight Type:
Survivors:
No
Site:
Schedule:
Reno - Susanville
MSN:
690-11374
YOM:
1977
Crew on board:
1
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
6984
Captain / Total hours on type:
782.00
Aircraft flight hours:
4052
Circumstances:
The pilot and flight nurse were en route to pick up a medical patient. The airplane experienced an in-flight breakup while flying by the leeward side of the sierra nevada mountains in the general area where standing lenticular clouds had been observed. No evidence was found that the pilot obtained a weather briefing from flight service or the duat vendors prior to departure. Pilots flying in the general area had reported airspeed variances from plus 60 to minus 40 knots. An in-flight weather advisory for occasional moderate turbulence was in effect. About one hour after the accident the weather service issued a sigmet for severe turbulence. Cause: an inadvertent encounter with severe turbulence which exceeded the design strength of the airplane's structure. Both occupants were killed.