Crash of a Rockwell Aero Commander 520 near Agoura Hills: 3 killed

Date & Time: Sep 26, 1982 at 1308 LT
Operator:
Registration:
N2622B
Flight Phase:
Survivors:
No
Site:
Schedule:
Hawthorne - San Luis Obispo
MSN:
520-134
YOM:
1954
Crew on board:
1
Crew fatalities:
Pax on board:
2
Pax fatalities:
Other fatalities:
Total fatalities:
3
Aircraft flight hours:
5198
Circumstances:
During departure, the pilot climbed in IFR conditions to 6,000 feet. After leveling, a frequency change was made and he was cleared to 8,000 feet, which he acknowledged. About 2 minutes later, the controller radioed to the pilot that he was about 4 miles north of the airway, but there was no reply from the pilot. Shortly after that radar contact was lost and the plane crashed in mountainous terrain. Several residents in the area reported hearing extremely loud engine noises followed by complete silence. An investigation revealed that both wings had separated outboard of their respective engine nacelle assemblies. An examination of the fractures revealed the wings had separated from positive overload. The leading edges of both wings had ballooned upward, indicative of extreme airspeed. The empennage had separated in a yaw and from right torsional overload. Parts of the aircraft were found within a 1 mile arc, north of the main impact area. The pilot's recent instrument experience could not be verified. All three occupants were killed. Turbulence was forecasted below 8,000 feet.
Probable cause:
Occurrence #1: loss of control - in flight
Phase of operation: climb - to cruise
Findings
1. (f) weather condition - clouds
2. (f) weather condition - turbulence in clouds
3. (c) aircraft handling - not maintained - pilot in command
4. (c) spatial disorientation - pilot in command
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Occurrence #2: airframe/component/system failure/malfunction
Phase of operation: descent - uncontrolled
Findings
5. Wing,spar - overload
6. (c) design stress limits of aircraft - exceeded - pilot in command
7. Wing - separation
8. Stabilizer - overload
9. Stabilizer - separation
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Occurrence #3: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Final Report: