What happened
On June 29, 2000, a Piper PA-25-235, registration EC-AZJ, was preparing for its first flight of the day to perform agricultural spraying operations. The aircraft was operating from an improvised runway located on a harvested barley field in the municipality of Cantalapiedra, province of Salamanca.
During the takeoff roll, the aircraft failed to reach the necessary speed to lift its tail. In an attempt to manage the aircraft's performance, the pilot deployed flaps; however, when the tail still failed to lift, the pilot performed an emergency release of the chemical payload. While the reduction in weight allowed the aircraft to become airborne, the aircraft struck the edge of a path located at the end of the runway, which sat approximately one meter above the level of the field. The impact caused the landing gear to break away from the airframe.
The pilot continued the flight to Matilla Aerodrome in Tordesillas, Valladolid, to perform an emergency landing. During the transit, the pilot monitored engine instruments and compensated for a rightward drift caused by damage to the right flap. The pilot landed successfully at Matilla, where emergency services were waiting.
The investigation
The investigation examined the takeoff conditions and the physical characteristics of the improvised runway. The takeoff surface consisted of a harvested barley field with a hard surface and stubble approximately 15 centimeters high. The runway was roughly 500 meters in length, situated at an elevation of approximately 900 to 1000 meters.
Investigators reviewed the aircraft's weight and balance, noting that while the aircraft was carrying a partial load of approximately 300 liters (out of a 568-liter capacity), the environmental conditions played a significant role in the takeoff performance. The weather was characterized by calm winds, high humidity, and temperatures between 18 and 20 degrees Celsius.
Findings
- The primary cause of the accident was that the aircraft did not achieve sufficient speed to lift the tail during the takeoff roll.
- The emergency release of the payload provided enough lift for the aircraft to become airborne, but the momentum carried the aircraft into the elevated embankment.
- Contributing factors to the insufficient takeoff speed included the presence of barley stubble on the runway, the elevation of the airfield, and temperatures above standard atmospheric levels, which collectively rendered the 500-meter runway insufficient for the takeoff requirements.