On February 18, 1997, at 0915 central standard time, a Piper PA-36-375 agricultural airplane, N7167E, was substantially damaged upon collision with a power line near Danevang, Texas. The commercial pilot, sole occupant of the airplane, was not injured. The airplane was registered to a private owner and being operated by Texas Ag-Air under Title 14 CFR Part 137. Visual meteorological conditions prevailed for the aerial application flight for which a flight plan was not filed. The airplane departed from the Texas Ag-Air Airstrip near Danevang, Texas, at 0845. According to the pilot, he had crossed over the "double pole" east-west cross country power lines several times while spraying herbicides on two adjacent fields. The pilot added that during the fifth spraying pass, he elected to cross under the power lines which he estimated to be suspended about 35 to 40 feet above the ground. As the airplane crossed under the power lines, at an estimated wheel height of 18 inches above ground level, the left main landing gear became entangled on a broken static wire that was left dangling from atop one of the 65 foot poles. The pilot further reported that the static wire, which had been previously cut by another airplane, had been pulled off the ground by the utility company and temporarily tied off so one portion of the cable was suspended about 5 to 6 feet off the ground. The pilot stated that the airplane decelerated "rather abruptly" as the gear was torn from the airframe, and the airplane impacted the ground in "a slight nose low attitude," skidding along the ground for 190 feet prior to coming to a stop in an upright position. Examination of the airplane by the FAA inspector confirmed that the airframe sustained substantial damage. The power company maintaining the power lines reported that a power interruption occurred on the evening prior to the accident; however, the downed static wire was left unmarked. Neither the property owner nor the operator of the airplane that initially cut the line had been notified of the downed line prior to the time of the accident.