On July 19, 2005, about 0630 mountain daylight time, a restricted category, turbine equipped, Grumman G164A (Ag Cat), N6702Q, sustained substantial damage after colliding with terrain shortly after takeoff from the Jerome Municipal Airport, Jerome, Idaho. The airplane is registered to Red Baron Ag Service, Inc, of Kimberly, Idaho, and was being operated as a visual flight rules (VFR) local aerial application flight under the provisions of Title 14, CFR Part 137. The commercial pilot, the sole occupant of the single seat airplane, was not injured. During a telephone conversation with the National Transportation Safety Board (IIC) on July 19, the pilot stated he departed runway 26 with a "slight" quartering tailwind. He reported that shortly after turning to the northeast, and clearing a series of power lines, the airplane developed a high sink rate. The pilot stated he increased power and jettisoned the load, however, the airplane continued to sink eventually impacting terrain, in a level flight attitude, approximately 1.5 miles north of the airport. According to the operator, the airplane was loaded with approximately 2,000 pounds of dry fertilizer and approximately 55 gallons of Jet A. The field elevation at Jerome is 4,048 feet above mean sea level (msl). The estimated density altitude (DA) was approximately 5,584 feet. The 0653 hourly METAR observation at Jerome was, in part, winds from 080 degrees (true) at 11 knots; visibility 10 SM miles; temperature, 20 degrees C; dew point 2 degrees C; barometric pressure 29.93. The operator reported that there were no mechanical malfunctions or failures with the airplane prior to the accident.