More on this from the Irish Independant
http://www.independent.ie/national-n...r-1307958.html
New info high-lighted below.
AN air traffic controller who allowed two passenger planes to come within 17 seconds of a mid-air collision is back on the job despite an air accident investigation report concluding that the near disaster was the result of "human error".
The radar controller and a planning controller, who are both stationed at Shannon, were immediately relieved of their duties and had their licenses withdrawn following the incident on September 23 last year.
The radar controller, who had less than two years experience in the job and was responsible for guiding the two planes, underwent extra training and has since returned to work.
An Air Accident Investigation report published yesterday found that the safety of the two planes was "seriously compromised". They came within 600 feet of each other and within 17 seconds of impact.
Tragedy was only averted when emergency safety systems onboard the aircraft alerted the pilots and they took evasive action.
The two planes got so close that the pilot on the Flightline aircraft said afterwards that he had "brief visual contact" of the other plane.
The probe found that the radar controller received four warnings -- one verbal warning from his planning controller and three electronic warnings - but failed to react to them on time. Instead the Traffic Alert and Collision Avoidance System (TCAS) on board the aircraft kicked in and instructed the Ryanair pilot to climb and the Flightline pilot to descend.
The report found that the controller had "inexplicably" cleared the Ryanair Boeing 737 to descend towards the path of the other aircraft, an MD-83.
Air traffic in the sector was light to moderate at the time and the two controllers were eight minutes from the end of their nine and a half hour shift. They also had a rest break less than an hour earlier.
Investigator Frank Russell said both controllers were sufficiently aware both aurally and visually that the two planes were on a collision course. But while they were both individually aware of the problem, their collective response was inadequate to the task, he added.
The planning controller, who has 30 years experience, pointed out to his colleague that there was a substantial speed difference between the two aircraft, however he took no further action as he was engaged in other duties.
Mr Russell said the younger controller had a "partial loss of his situational awareness" which led him to take incorrect and potentially dangerous decisions. His belated attempts to rectify the situation were overtaken by the aircrafts' TCAS. "The safety (of the two aircraft) was seriously compromised by the failure of the radar controller to maintain a safe flight level between the two aircraft. There were no electronic/technical reasons which contributed to this failure. This was human error," concluded Mr Russell.
He said disaster was averted by the last line of defence, the aircrafts' on-board TCAS, and not by the intervention of air traffic controllers.