An investigation into an air accident near miss involving an Air Malta Boeing 737 and an Italian ultra-light aircraft has said that the fact that a radar return could be seen on the radar recordings but could not be seen on the radar display at the time of the incident "cannot be explained".
The near miss occurred in April last year and an accident was only avoided in the nick of time thanks to evasive action by the Air Malta pilot.
"While the intercom conversation and the controller statements confirm that the light aircraft was not observed on the radar displays, the radar recordings indicate otherwise. It may be surmised that, if the primary radar return was noted by the controllers, especially when this return changed course and came into the path of the DI (the Air Malta aircraft), then appropriate evasive action would have been taken by altering the course of the aircraft under positive control, namely DI. The investigation found no evidence that such action was taken," a report tabled in Parliament says.
It adds that although both radar manufacturer software engineers confirmed conclusively that the radar recordings of the occurrence were a faithful reproduction of what was actually displayed on the radar screens at the time of the incident, "whether or not any of the controllers on duty actually saw a primary radar return of the ultra-light aircraft cannot be determined".
There was, however, no evidence that the radar system was not functioning correctly during the course of the incident.
The report concluded that, among the causes of the accident near miss was the absence of a transponder on the light aircraft, lack of knowledge by the pilot of the light aircraft in emergency radio telephony procedures and "failure of air traffic controllers to observe the apparent radar plot of I-6293" (the light aircraft).
Among other recommendations, the investigators said Malta Air Traffic Services should use this report during recurrent training programmes to ensure awareness of the occurrence among air traffic control officers. "Furthermore an evaluation of work practices and standard operating procedures should be undertaken."
The pilot of the light aircraft had claimed he had slipped into the flight path of the Air Malta aircraft to make an emergency landing because of low fuel. However, no tests were taken to check whether this claim was true. The Italian pilot claimed he had unsuccessfully tried to contact Malta air traffic control on radio.
Chief Inspector of Accidents Capt. Denis Caruana has criticised the fact that substantial excerpts from the investigation report were leaked to The Sunday Times in contravention of the law.