Accident Overview
On Monday, June 3, 2024, at 10:45 local time, an Air Tractor AT401, registration EC-IYL, sustained substantial damage during a takeoff attempt from the Isla Mayor runway, an airstrip located on a partially asphalted road south of Isla Mayor, Seville. The pilot, who was the sole occupant, exited the aircraft with minor scratches and was otherwise uninjured. The aircraft came to rest inverted at the end of the runway in a ditch, oriented opposite to the takeoff direction.
Aircraft and Crew Information
The aircraft, an Air Tractor AT-401 serial number 401-0739, had accumulated 6,713:45 total flight hours. It was powered by a Pratt & Whitney R-1340-AN1 radial piston engine (serial number 15977) with 196:05 hours since overhaul, rated at 550 hp maximum continuous power. The owner and operator was Martínez Ridao Aviación.
The 59-year-old pilot held a valid CPL(A) license with ratings for AT-4/5/6/8 SET and SEP, and a valid medical certificate. His total flight experience was 5,433:40 hours, of which 789:16 hours were on the AT401. He had been flying agricultural operations for 28 years and had recently transitioned from an AT802 to the AT401, completing a check and training flight 15 days before the accident. He had been flying the accident aircraft exclusively for the preceding week.
Flight and Circumstances
The flight was an agricultural sowing operation for rice. Each mission consisted of short cycles: loading seeds and water, takeoff, flight to the flooded field, low-level seed dispersal, and return for reload. On the accident day, the pilot had completed a first flight of 12 cycles from 07:20 to 09:30. The second flight was planned with 10 cycles. Before the accident, the aircraft was refueled with 365 liters of fuel, 500 kg of seeds, and 75 kg of water to moisten the seeds.
The pilot reported high temperature and a tailwind of variable intensity and gusty conditions, worse than during the earlier flight. Aware of the wind, he performed a static takeoff (applying power with brakes set) with flap setting between the second and third detent. He released the brakes, and the aircraft began its takeoff roll. Upon reaching the midpoint of the runway without becoming airborne, the pilot decided to execute an emergency dump. However, the seed discharged more slowly than expected, and the seed release could not be completed. The aircraft lifted a few meters but could not sustain flight and descended, impacting terrain. It ended inverted beyond the runway end.
Investigation Findings
The technical investigation concluded that the probable cause was a takeoff conducted under conditions of weight, altitude, temperature, wind, and incorrect flap setting that required more runway length than available, combined with incorrect preflight performance calculations. No safety recommendations were issued.
Damage
The aircraft sustained significant damage to both wings (especially the left), engine, and tail assembly. No other property was damaged.