Italy

The cause of the accident was due to an impact with the ground resulting from the loss of control of the aircraft by the captain, who was also the PF. It appears very likely that during the initial phase inadequate attention was replaced by a phase of spatial disorientation, resulting in a loss of situational awareness, which prompted an inadequate intervention on the flight controls by the PF, resulting in total loss of control of the aircraft (having accentuated the tilt to the left wing, instead of leveling the aircraft). It is reasonable to assume that the PF, based on the conviction of being in a right turn for Bolsena in IMC night conditions, misinterpreted the unusual turn, using the controls in order to accentuate the bank angle to the left, drastically reducing the vertical component of lift. This turn has consequently caused the aircraft to assume an attitude of increasing bank, a condition that has been aggravated by the continued application on the controls of a positive load factor in order to stop the sudden loss of altitude, without first leveling the wings. Or the aircraft is stabilized in a pronounced downward spiral to the left. The first officer (PNF), engaged in the management of navigation equipment, has created the unusual turn of the aircraft in conjunction with the commander (PF). Nevertheless, the considerable gradient of experience on the airplane and hierarchy within the organization between the captain and the first officer has probably prevented him to intervene in a more directive or authoritative way in the recovery phase of the situation. Also contributing to the outcome of the event was the lack of detail in the definition of the duties of the crew procedures and inadequate adherence to the basic principles of CRM/MCC, with reference to the monitoring and statement of the navigation modes active, navigation procedures and in particular to the lack of requests for inclusion of turns and routes, the deficiency in the performance of controls and optimization of automation that can lighten the workload in a time unfavorable from the point of view of the circadian rhythm and IMC night. In this respect, it seems fitting to remember the problem of spatial disorientation, although known and studied for decades, is still relevant, and that the only way to counter it is the application of proper use of instruments in compliance with the basic principles of CRM/MCC, which should be part of the normal operating procedures of an operator. This is especially true when working outside of normal circadian rhythms, when it is most easily seen a slowing of cognitive processes.

The accident has been caused by an unexpected loss of both engines thrust as a consequence of a massive bird strike, during the go-around manoeuvre. The loss of thrust has prevented the aircrew from performing a successful go around and has led the aircraft to an unstabilized runway contact. The following factors have contributed to the event:
- The inadequate effectiveness of bird control and dispersal measures put in place by the airport operator at the time of the accident,
- The captain decision to perform a go around, when the aircraft was at approximately 7 seconds from touchdown. The above decision was significantly influenced by:
- The lack of instructions to flight crew concerning the most suitable procedures to adopt in the case of single or multiple bird strikes in the landing phase,
- The absence of specific training in the management, by the flight crew, of the "surprise" and "startle" effects in critical phases of the flight.

A loss of control as a result of an aerodynamic stall while completing a left turn due to an insufficient speed. During the last turn facing the setting sun, the pilot-in-command reduced the engine power excessively, possibly after suffering a loss of situational awareness. The short distance between the aircraft and the ground did not allow the crew to expect a stall recovery.

Even if it was not possible to define with certainty why the aircraft impacted against the ground, it is nevertheless considered reasonable that the impact occurred as a result of improper management of the manoeuvre by the crew, the result of an inadequate assessment by the crew of the flight altitude with respect to the top of the hill and the critical environmental conditions, characterized by the presence of strong turbulence, strong wind and visibility affected by the presence of smoke. (The cause of the accident would therefore be substantially due to human and environmental factors).

The pilot lost control of the aircraft, resulting in a collision with the ground. For reasons that investigations have not been able to determine with precision, the twin engine aircraft deviated from its intended course to the east. The lack of visibility caused by night could remain a contributing factor in that the pilot was not able to distinguish the ground and determine his position accurately. The analysis of the flight path and the debris of the aircraft did not make it possible to provide convincing and objective evidence on the possibility of an in-flight structural failure, of a technical failure of the flight controls or any alteration in the psychic or physical abilities of the pilot.

The very high state of fragmentation of the wreck and the substantial absence/utilisation of FDR data made the safety investigation very difficult and therefore could not acquire some indisputable certainties on certain aspects. The indications resulting from the examination of the acquired evidence and from the many technical analyses carried out lead to believe that the accident occurred because of the loss sudden control of the aircraft, induced, reasonably speaking, by a technical problem in the flight control system, which the pilots were unable to counter/manage and which the safety investigation could not detect with absolute certainty.

The accident, reasonably triggered by a technical problem that the investigations could not identify with indisputable certainty, was attributable to an in-flight loss of control of the aircraft following an aerodynamic stall at low altitude during initial climb. The pilot's attempt to return to the airport was unsuccessful and the short distance between the aircraft and the ground did not allow him to expect a stall recovery.