Italian crash investigators have found the flight data recorder of an Air Algérie Lockheed Martin L100-30 Hercules that crashed near Piacenza in northern Italy on August 13.

The flight data is “almost destroyed but we will do our best,” says Italy’s Agenzia Nazionale per la Sicurezza del Volo (ANSV).

The ANSV had already found the aircraft’s cockpit voice recorder, which was readable despite significant damage.

“Preliminary analyses showed that during normal cruise conditions on top of clouds with autopilot engaged, the autopilot FAIL light came on and after twelve seconds the autopilot disengaged. A few seconds later the aircraft lost irreversibly directional and longitudinal control.” The impact happened 73s after the autopilot fail light came on.

Data from Milan and Zurich air traffic control and the Italian air force’s radar systems about the final stages of the flight trajectory is still being analysed.

The ANSV says footage from a security camera at a petrol station nearby shows the last seconds of the flight, and allows the angle of impact to be estimated at between 45° and 50° and the speed at impact at 460-485kt (850-900km/h).

The investigators have also revealed further details on the crash site, which killed the three crew on board the aircraft. The aircraft, registration 7T-VHG, was destroyed when it hit the ground following a high-rate descent from 24,000ft (7,300m). The impact caused a crater around 50m long and 15m wide.

“The upper part of the rudder and part of the elevator were respectively found at 1,200m and 3,000m before the impact point. Detailed fractographic analyses are currently ongoing on these parts.”