What happened
On the day of the accident, the flight originally operated under instrument flight rules before the crew cancelled the IFR flight plan at 13:53:09 UTC, proceeding under visual flight rules. While communicating with the Zurich sector south air traffic controller, the crew requested to remain on their current frequency for an additional two minutes before transitioning to Samedan Information. During this period, the aircraft was traveling on a south-westerly heading near Zernez.
Upon establishing contact with Samedan Information, the crew reported being ten miles from the threshold of runway 21, though the aircraft was actually positioned approximately eight miles north-east of that point. While near Zuoz, the crew inquired about the weather conditions at the aerodrome. As the aircraft passed over Madulein, the flight information service officer confirmed that landing could proceed at the crew's discretion. Following this, the aircraft began a rapid descent, exceeding 2200 ft/min, reaching a radio altitude of less than 250 ft as it crossed the runway threshold.
After crossing the threshold, the crew attempted to climb to 600 ft and maneuvered parallel to the runway centerline. The aircraft's landing gear was down and flaps were likely set to 20 degrees. As the aircraft transitioned to the downwind leg at the end of the runway, it entered a right turn with a bank angle of 55 degrees and an increase in speed. During the subsequent turn onto the final approach, the bank angle increased to 62 degrees. During this maneuver, the Piaggio 180 inverted and struck the ground in a near-vertical descent. The impact resulted in two fatalities and the total destruction of the aircraft. The crash severed a power line, causing an outage in the Upper Engadine valley and triggering an explosion-type fire.