Maricopa, AZ, USA
N6059L
Air Tractor AT-802 A
The orientation of the runway was 340 degrees. The weather at the nearest reporting station indicated that the winds were from 100 degrees at 6 knots. This would have resulted in a 4-knot rear quartering tailwind and a 2-knot crosswind from the right. Using the performance data listed in the airplane's pilot operating handbook, the landing distance was calculated to be 2,109 feet, without using reverse. The Gila River West runway on which the accident occurred was 2,400 feet long. Assuming that the airplane was flown at the reference speed of 73 knots, with no wind, and touched down on the threshold, there would have been only 291 feet remaining on the runway. The tailwind present at the time of the accident would have increased the landing distance required, and thereby reducing the available runway. The presence of an irrigation sump at the end of the runway would have eliminated any margin for error, and made it impossible to overrun the runway safely. The placement of a truck along the side of the runway at the departure end further limits available options in the event of a long landing or overrun. Under the conditions at the time of the accident, there would have been no allowance for error either in pilot technique, or in a real or perceived mechanical malfunction. These factors would force the pilot to make sudden, last minute maneuvers to avoid obstacles at the end of the runway. During an engine inspection, performed by factory personnel, and witnessed by an inspector from the Federal Aviation Administration Southwest Manufacturing District Office (FAA MIDO-41), the engine was operated up to 30 percent of its power range with no anomalies noted. The power was reduced to idle several times and the propeller did not feather. The propeller operated throughout the operating range, including beta, with no defects noted. It was noted that with the power lever in the full aft position, the beta plunger was slightly depressed. This may have been enough to allow the propeller to go slightly past the low pitch stop, toward reverse, when the power lever was pulled back to the idle position. It was observed that rubbing had occurred between the two controls. The FAA inspector and assisting personnel attempted to force the throttle lever to move the propeller control lever aft. The two levers did move aft together, only when the power lever was pulled inboard against the propeller control lever. However, the propeller control lever could not be made to move past the feather detent. If the throttle had been closed, the propeller would move to the low pitch (high rpm) position even with the propeller control pulled aft to the control stop.
On March 10, 2001, at 1045 hours mountain standard time, an Air Tractor AT-802-A, N6059L, was substantially damaged after striking a vehicle while landing at Gila River West, an agricultural airstrip, Maricopa, Arizona. The commercial pilot, and sole occupant, was not injured. Visual meteorological conditions prevailed for the flight conducted under 14 CFR Part 137. The airplane had originally departed the agricultural strip at 1030, and was returning to Gila River West to reload. No flight plan was filed. The pilot stated that he was on his 10th landing of the day at this particular agricultural strip when the accident occurred. According to the pilot, he was returning to refill with fertilizer when the propeller feathered in the landing flare. He believed that the resulting loss of drag caused him to float much farther than normal. There was a rectangular irrigation sump in line with the runway at the departure end. To avoid landing in the sump, he attempted to redirect the airplane to a field on the right side of the strip. After diverting to the right side of the landing area, the left wing struck a fertilizer delivery truck, which was parked on the right side of runway, at the departure end. The airplane ground looped and came to rest on the east edge of the irrigation sump. The orientation of the runway was 340 degrees. The weather at the nearest reporting station indicated that the winds were from 100 degrees at 6 knots. This would have resulted in a 4-knot rear quartering tailwind and a 2-knot crosswind from the right. According to the manufacturer, the maximum demonstrated crosswind component for this airplane is 20 knots. Using the performance data listed in the airplane's pilot operating handbook, the landing distance was calculated as follows. At a reference speed of 73 knots, in a no wind condition, at a pressure altitude of 1,155 feet, an air temperature of 18 degrees Celsius, and a landing weight of 9,250 pounds, the total landing distance over a 50-foot obstacle was 2,109 feet, without using reverse. The Gila River West runway, on which the accident occurred, was 2,400 feet long. The airplane was transported to the Air Tractor, Inc., production facility in Olney, Texas, and inspected. The engine was operated while still attached to the airframe. An inspector from the Federal Aviation Administration Southwest Manufacturing District Office (MIDO-41) was present for the inspection and operation of the engine. The engine was operated up to 30 percent of its power range with no anomalies noted. The power was reduced to idle several times and the propeller did not feather. The propeller operated throughout the operating range, including beta, with no defects noted. The inspector noted that the power control rigging was within acceptable limits with the exception of the beta plunger. It was noted that with the power lever in the full aft position, the beta plunger was slightly depressed. Closer inspection of the power quadrant revealed control interference between the throttle and propeller levers. It was observed that rubbing had occurred between the two controls. The FAA inspector and assisting personnel attempted to force the throttle lever to move the propeller control lever aft. The two levers did move aft together, only when the power lever was pulled inboard against the propeller control lever. However,
Inadequate selection of landing facilities and improper placement of vehicles near the runway. An additional factor was the use of a runway which resulted in a downwind landing.
Source: NTSB Aviation Accident Database
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