On August 11, 1993, at 1045 Pacific daylight time, a Hiller UH- 12E helicopter, N100LM, collided with a guy wire strung between two power poles and crashed while attempting a forced landing in a field near Dixon, California. The aircraft was operated by Pacific Valley Aviation, Inc., Arbuckle, California, and was on an aerial application flight dispensing insecticides at the time. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The aircraft was demolished in the collision sequence. The certificated commercial pilot, the sole occupant, sustained serious injuries. The flight originated from a truck near the accident site at about 1025 hours on the day of the mishap. An FAA inspector from the Sacramento, California, Flight Standards District Office examined the aircraft and the accident site, and, in addition, interviewed witnesses to the accident. In his report, the inspector said the helicopter had been working the field for about two hours dispensing insecticides. The pilot departed the truck after refueling to finish the remaining corner of the field being sprayed. The field is bordered by a set of power lines on wooden poles with a wire height about 40 feet AGL. The pilot was flying under the power lines during his spray runs. The last two poles had a one quarter inch guy wire strung between them about half way up the poles. On the final pass in the field, the helicopter collided with the guy wire. Based on his inspection of the wreckage and witness observations, the inspector reported that the helicopter collided with the wire at a point between the rotor hub and the swash plate assembly, breaking the pitch change links. The pilot was able to regain partial control of the helicopter and was attempting a run on landing cross furrow in a tomato field about two miles from the wire strike. The helicopter skids caught on both the plants and the soft furrows and tumbled to a stop.