SEA99LA115

The pilot took off with 1,700 pounds of fertilizer (within the airplane's maximum demonstrated operating load) and approximately 3/4 fuel on an aerial application flight. The airstrip the pilot took off from slopes uphill at the end. The pilot stated that at an altitude of 5 to 10 feet above the ground after takeoff, 'a tailwind came up' and he was unable to stay airborne. The aircraft settled into a wheat field and flipped over approximately 500 feet past the end of the airstrip. The pilot reported that no mechanical malfunction or failure was involved in the accident. He reported the accident site was 4,300 feet above sea level, and that temperature at the time of takeoff was 92 degrees F. Density altitude at this pressure altitude and temperature was 7,500 feet.

On July 12, 1999, approximately 1600 mountain daylight time, an Ag Cat (formerly Grumman-Schweizer) G-164B agricultural aircraft, N8005C, owned by Ruchert Flying Service of Pomeroy, Washington, was substantially damaged when it settled into a wheat field and flipped over on initial climb following takeoff from a private airstrip approximately 8 miles north of Paul, Idaho. The commercial pilot-in-command of the aircraft was not injured in the accident. Visual meteorological conditions prevailed and no flight plan had been filed for the local 14 CFR 137 agricultural aerial application flight.

The pilot reported he took off with a load of 1,700 pounds of dry fertilizer (the aircraft type certificate lists the maximum hopper capacity as 2,000 pounds, and the operator had demonstrated satisfactory operation of the aircraft with up to 3,200 pounds hopper load per Civil Air Manual [CAM] 8), and with 90 gallons (approximately 3/4 of the aircraft's fuel capacity, according to the pilot) of Jet A fuel on board (the aircraft was equipped with an AlliedSignal TPE331-1-151G turboprop engine rated at 665 shaft horsepower.) The pilot reported that temperature at the time was 92 degrees F, and that the accident site elevation was 4,300 feet above sea level. Density altitude at a pressure altitude of 4,300 feet and temperature of 92 degrees F was computed by the NTSB investigator-in-charge to be approximately 7,500 feet. The pilot reported the east-west oriented gravel airstrip is approximately 3,000 feet long, and that winds at the time were from 245 degrees at 4 knots, with unknown gusts. The pilot stated:

...I took off to the east and got airborne approx[imately] 5-10 [feet] above the runway when a tailwind came up about then, by then I was near the end of the runway, which starts to incline, so I climbed to get over that and got near the top and the [aircraft] had slowed, so I opened the gate to get rid of some weight and went over the top of the hill and got the nose down and followed the terrain down into a little dip and then up over another little hill. [Then barely] cleared that obstacle and settled into the wheat below me[, approximately] 500 [feet] past the end of the runway. [The aircraft] settled in in [sic] a three point attitude and the [aircraft] flipped over forward and hit tail first and continued over till it came to rest on the main gear and nose of the aircraft.

The pilot reported on his NTSB accident report that to his knowledge, no mechanical malfunction or failure was involved in the accident.