What happened
On June 10, 2008, at approximately 17:35 UTC, a Cessna C152, registration CS-DGV, operated by Nortávia, was performing a training flight near Santarém. The flight was intended to provide necessary hours for a pilot's license renewal. After departing Santarém, the crew received clearance from the Flight Information Service (FIS) to climb to 2,000 feet AMSL.
Simultaneously, a privately owned Piper PA-28-140 Cherokee, registration CS-DCQ, was conducting a local leisure flight in the same area. The Piper was operating under visual flight rules (VFR) without a transponder active and was not being monitored by the FIS.
As the Cessna reached its assigned altitude, the Piper positioned itself directly above the Cessna. Because the Piper is a low-wing aircraft and the Cessna is a high-wing aircraft, the positioning created a blind spot for both crews. The instructor in the Cessna had previously identified the Piper at the 5 o'clock position, roughly 50 meters away, but lost visual contact during the maneuver. Shortly after, the crew heard a loud impact and saw debris from the Piper's landing gear pass in front of their windscreen.
The collision caused severe damage to the CS-DGV, including the loss of its propeller and damage to the flaps and rudder. The instructor managed to execute an emergency landing in a cultivated field. The CS-DCQ also performed an emergency landing in a nearby field, where the impact caused the aircraft to catch fire. The three occupants of the Piper sustained injuries, including one adult passenger who suffered permanent vision loss in one eye, but all were able to evacuate before the aircraft was consumed by flames.
The investigation
The GPIAAF investigation examined the flight paths, maintenance records, and cockpit communications. The investigators established that the Cessna was operating according to its flight plan and maintenance schedule, and the pilot-instructor was fully qualified. The Piper was also found to be in a valid state of airworthiness. The investigation focused on the visual separation failure and the positioning of the two aircraft at the moment of impact.
Findings
- The primary cause was a mid-air collision between the Piper PA-28-140 Cherokee, CS-DCQ, and the Cessna C152, CS-DGV.
- The positioning of the low-wing Piper directly over the high-wing Cessna obstructed the pilots' ability to maintain visual separation.
- The pilot of the Piper lost situational awareness regarding the distance to the other aircraft.
- The crew of the Cessna had lost visual contact with the Piper after it moved into a position where it was no longer visible.
- The collision involved a violation of ICAO Rules of the Air regarding protection of persons and aircraft proximity.
- The Piper's landing gear struck the upper portion of the Cessna, leading to the subsequent emergency landings and the destruction of the Piper.