What happened
On April 19, 2010, at approximately 14:30 UTC, a Piper PA-36-300 was conducting an agricultural spraying mission over the Santa Marta estate. The aircraft had departed from Jaramillo runway carrying 125 gallons of agricultural oil and 40 gallons of fuel.
After completing an initial pass from south to north, the pilot initiated a right-hand turn at a 90-degree angle. When the aircraft reached a 69-degree bank, the pilot attempted a left-hand turn to reposition for a second pass. During this maneuver, the aircraft lost lift and descended rapidly, striking the treetops of a nearby mound at an altitude of approximately 85 meters above the plantation level. The pilot was able to abandon the aircraft on his own.
The investigation
The investigation focused on the flight dynamics, meteorological conditions, and pilot performance. Investigators analyzed GPS data, which revealed a gradual decrease in airspeed as the aircraft climbed during the turns. At the start of the right turn, the ground speed was 175.3 km/h; by the time the aircraft began to descend, the speed had dropped to approximately 123.8 km/h. Based on the aircraft's weight of 3,865.6 lbs, the calculated stall speed was approximately 78 mph.
Meteorological analysis ruled out mountain waves or significant anabatic/katabatic winds, as conditions were calm with no significant terrain-induced turbulence present. The investigation also examined the pilot's actions regarding the aircraft's flaps and load release. While the pilot claimed he attempted to jettison the load and deploy 10 degrees of flaps to gain time, physical evidence showed the flaps remained retracted and the load had already been expelled.
Findings
- The pilot failed to maintain the required safety speed during a low-altitude maneuver.
- The pilot's attention was diverted by a momentary engine 'surging' or 'torpedoing' sensation, which caused him to focus on engine instruments rather than airspeed monitoring.
- The pilot did not perform a prior aerial reconnaissance of the area to identify fixed obstacles, as required by regulations.
- The decision to execute turns toward the hills, rather than away from them, increased the risk of terrain impact.
- The workload during the final seconds—attempting to jettison cargo and adjust flaps while avoiding trees—exceeded the pilot's capacity to react effectively.