Irish airlines to blame for 14% of near miss incidents

IRISH airlines were responsible for over 14% of potentially dangerous aviation incidents known as “level busts” — which increase the risk of a mid-air collision — in British airspace last year.

Figures provided by NATS, the main British air navigation services provider, show that Irish-registered aircraft have been involved in 124 separate level busts since 2004.

It is believed the vast majority of such incidents involve flights operated by Ryanair and to a lesser extent, Aer Lingus.

A “level bust” is officially categorised as any deviation of more than 300ft from the flight altitude of the aircraft set by air traffic controllers, or 200ft in congested areas, such as in the vicinity of airports.

The number of level busts in Irish airspace is also set to increase in 2007 as 34 cases have been recorded so far this year. The total for 2006 was 35.

Aviation authorities across Europe have become increasingly worried about the issue as level busts have increased over the past few years at a rate in excess of growth in air traffic.

Eurocontrol — the European Organisation for the Safety of Air Navigation, of which Ireland is a member — believes level busts pose “a real and pressing” danger.

A level bust was blamed for the worst mid-air collision in aviation history when two passenger jets crashed near Delhi, India with the loss of 349 lives in November 1996.

Although the vast majority of level busts pose no threat to aircraft because most civilian aircraft are equipped with anti-collision warning systems, air safety experts point out that there is still a risk because aircraft are increasingly flying in much closer proximity due to overcrowded skies in Europe.

Around 1,200 level busts involving civilian aircraft have been recorded in British airspace since January 2004, while private and military aircraft are responsible for at least another 300 cases. Over 10% of these incidents resulted in a loss of the standard safe separation limits between the flight and other aircraft, which is colloquially known as a “near miss”.

However, aviation experts estimate that the number of reported cases represents only about 30% of the true incidence of level busts.

According to the Irish Aviation Authority, two out of 34 level busts recorded this year resulted in a “technical loss of separation”, although neither incident posed any risk to the safety of aircraft.

US airlines and private business jets account for approximately half of all level busts in Irish airspace.

“Level busts have the potential for high risk. However, the incidence [of level busts] in Irish airspace is low and is assessed as low risk,” said an IAA spokesperson.

The IAA said all level busts were identified under a mandatory reporting regime and were investigated in order to prevent a recurrence of a similar situation.

Several studies have shown there are a number of reasons why level busts occur. The overwhelming majority relate to human error caused by confusion over instructions issued by air traffic controllers to pilots.