Aviation Accident Summaries

Aviation Accident Summary FTW97LA012

IDALOU, TX, USA

Aircraft #1

N4533H

Air Tractor AT-502

Analysis

According to an FAA inspector, the pilot was attempting to depart his 2,300 foot long dirt airstrip with a 3,040 pound payload of cotton defoliant for a local aerial application flight. He stated that the airplane failed to become airborne and overran the departure end of the airstrip. He added that the airplane managed to break ground, but its wheels dragged on cotton plants and eventually decelerated the airplane to the point where the flight could not be maintained. Subsequently, the airplane encountered furrows perpendicular to its takeoff path and was damaged. The pilot stated that 'the gross weight of the airplane exceeded the ability of the airplane to become airborne within the length of the runway.' The pilot added that 'attempts to jettison the load near the end of the strip were not in sufficient time to prevent running off the end of the runway.' Based on figures provided by the operator, the density altitude was calculated to be 9,500 feet. The approved airplane flight manual did not provide performance data on the required takeoff roll for this flight.

Factual Information

On October 8, 1996, at 1745 central daylight time, an Air Tractor AT-502, N4533H, was substantially damaged during takeoff from a private airstrip near Idalou, Texas. The airplane, owned and operated by Everitt Aerial Spraying Inc., was being operated under Title 14 CFR Part 137 at the time of the accident. The commercial pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed for the flight for which a flight plan was not filed. The flight was originating at the time of the accident. According to the FAA inspector, the pilot was attempting to depart his 2,300 foot long dirt airstrip with a 3,040 pound payload of cotton defoliant for a local aerial application flight. The pilot told the FAA inspector that the airplane failed to become airborne and overran the departure end of the airstrip impacting furrows perpendicular to the aircraft takeoff path. In the narrative portion of the enclosed NTSB Form 6120.1/2, the pilot stated that "the gross weight of the airplane exceeded the ability of the aircraft to become airborne within the length of the runway." The pilot added that "attempts to jettison the load near the end of the strip were not in sufficient time to time to prevent running off the end of the runway." During a telephonic interview with the investigator-in-charge, the pilot stated that he had been operating from the same runway with a 350 gallon load (500 gallon hopper) all afternoon. The pilot stated that he was aware that the chemical being sprayed on the last flight was changed over to a heavier chemical, and he expected the takeoff roll to increase by another 50 to 100 yards. He added that the airplane managed to break ground as he anticipated, but the wheels of the airplane dragged on the cotton plants and eventually decelerated the airplane to the point where the flight could not be maintained. Examination of the airplane by the FAA inspector revealed that the left main landing gear collapsed and the left wing sustained structural damage. The flaps were found in the retracted position; however, the pilot stated that he used flaps for takeoff and he retracted them prior to exiting the airplane. Based on figures provided by the operator, the density altitude at the time of the accident was calculated at 9,500 feet. The approved airplane flight manual does not provide any performance data on the required takeoff roll for this flight.

Probable Cause and Findings

the pilot's improper planning/decision, which resulted in an overrun during takeoff and an encounter with cotton (crop) and rough/uneven terrain. Factors relating to the accident were: the excessive loading of the airplane for the existing conditions, the short runway, the high density altitude, and the pilot's delay in jettisoning the load.

 

Source: NTSB Aviation Accident Database

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