TWO AIRCRAFT came within 17 seconds of a mid-air collision last September because of the "critical failure" of air traffic controllers based at Shannon, a report has concluded.
The two aircraft - one a Flightline charter with 170 passengers and crew flying from Faro to Dublin, the second a Ryanair aircraft travelling from Stansted to Cork with 185 passengers and crew - came within 180 metres (600ft) of each other vertically off the southeast coast. The minimum recommended distance is 300m (1,000ft). The incident occurred about 60km (37 miles) off the coast of Co Wexford at 7.51pm on September 23rd last year.
The Air Accident Investigation Unit (AAIU) said a mid-air collision was only "narrowly avoided" and blamed a radar controller and a planning controller based at Shannon.
The radar controller ignored four warnings, one verbal and three electronic, that the aircraft were closing on each other.
It happened when the radio controller cleared the Ryanair aircraft to descend from 30,000ft to 29,000ft and then to 10,000ft. That command brought it into the path of the Flightline aircraft which was cruising at 28,000ft.
A potential collision was avoided by the intervention of the aircrafts' traffic alert/collision avoidance systems and evasive action by the pilots.
In the final report, AAIU inspector Frank Russell said there was a "critical breakdown" in communication. The planning controller, who had 30 years of experience, had become distracted by an operational call from management at Shanwick (Prestwick air traffic control) in Scotland.
He failed to notice the radar controller had cleared the Ryanair aircraft to descend to the flight path of the Flightline aircraft when "urgent action to the contrary" was needed.
Mr Russell held the radio controller had a "partial loss of situational awareness" in terms of where both aircraft were in relation to each other.
The pilots took action after their avoidance systems were issued a resolution advisory command to take evasive action, which the inspector described as the "last line of defence".
The two controllers were removed from their duties and their licences to operate as air traffic controllers withdrawn, which is normal procedure following such incidents.
They were offered counselling services and the radio controller underwent a training programme tailored to the lessons arising from the event and was later reinstated, according to the Irish Aviation Authority.
It had accepted all the safety recommendations made in the report by the AAIU which called for reviews of training and on-site procedures and the appointment of a standards officer in Shannon.
Spokeswoman Lilian Cassin said the aviation authority handled 10,000 flights a week.
"The IAA, and Ireland, has an excellent air safety record and, as acknowledged in the report, the AAIU has not investigated an incident of this seriousness in the previous seven years," she said.
In 2001, an Air France flight from Havana to Paris came within two minutes of mid-air collision with an Airtours Airbus A330 en route from Cancun, Mexico, to London in Irish air space. The report into that incident blamed air traffic controllers at Shannon and Prestwick and the cockpit crew of the Airtours aircraft.
