On October 1, 1996, approximately 0900 central standard time, a Continental Copters-Darling El Tomcat MK-5A helicopter, N7MH, was substantially damaged after impacting terrain during takeoff near Lafayette, Louisiana. The commercial pilot, sole occupant who owned and operated the agricultural helicopter, sustained serious injuries. Visual meteorological conditions prevailed and no flight plan was filed for the Title 14 CFR Part 137 aerial application flight. The pilot reported that he and his ground crew were preparing to commence an aerial application job for a farmer who was reportedly "anxious" to get the job underway. The helicopter was transported to the job site on a trailer from which it was normally operated. After a pre-flight, the pilot prepared to take off from the trailer. Upon lift off, the rear portion of the left skid became "snagged" on the left rear tie down. According to a witness and the pilot, the aircraft "pitched up, rolled left", and at "least one of the main rotor blades struck the ground." Subsequently, the skid broke loose from the tie down, and the nose pitched down and impacted the ground. During this sequence, the tail boom separated from the helicopter. The pilot reported that he and his ground crew were fatigued when they arrived on the job on the morning of the accident. He stated that during a 168 day time period, he had worked 164 days, flown over 400 hours, and spent approximately 656 hours driving to jobs. He reported his normal work day to be 0500 to 2300 (allowing 6 hours for sleep). In an interview with the investigator-in-charge, the pilot stated that he requires an average of 8 hours of sleep per day to feel fully rested. He submitted the following calculations to quantify his reported fatigue: 164 days X 8 = 1312 hours 164 days X 6 = 984 hours 1312 minus 984 = 328 hours total sleep deficit in 168 days prior to the accident. The above calculations are similar to data that are currently being studied at the NASA AMES Research Center regarding fatigue and work/sleep cycles in the transportation industry. The NTSB and NASA sponsored a "Fatigue Symposium" on November 1-2, 1995, at Tyson's Corner, Virginia. The symposium proceedings were published and are available through the NTSB, Office of Public Inquiries, Washington, D.C.