By David Kaminski-Morrow in London

Europe’s air traffic co-ordination authority has disclosed that UK airport traffic was 16% down overall as a result of the disruption prompted by yesterday’s national security alert.

Brussels-based Central Flow Management Unit, which balances capacity against demand in European airspace, states that London Heathrow traffic was 48% lower compared with the same day in the previous week.

Eastbound transatlantic traffic fell by 20% although the gradual release of long-haul flights during the day kept the reduction of westbound services to 7%.

CFMU was initially made aware of a potential problem at 05:00 Central European time when it was advised by UK authorities about the heightened security situation.

“Already there were issues at UK air traffic centres because staff were being checked,” says CFMU assistant head of operations Brian Flynn. The CFMU activated its crisis-management strategy in order to cope.

Serious restrictions were imposed from 08:00 when London Heathrow’s normal arrival rate of 45 flights per hour was slashed to just 15.

As the airport struggled to cope with the backlog of departures, and gates remained occupied, the rate was further reduced until Heathrow was effectively closed to all arriving traffic.

But by 13:00 the situation had eased enough to re-admit flights from four European countries – Germany, France, Belgium and Switzerland – and to raise the arrival rate at the hub to 35 per hour.

“Although the infrastructure could accept the flights the terminals were still crowded,” says Flynn. Traffic routes from another four European states were opened at around 14:00 and by 15:00 Heathrow was made available to all flights, although the 35-per-hour arrival rate stayed in place.

There were no flow restrictions imposed on departures but the security situation and cancellation of earlier arrivals led to a much-reduced departure rate from Heathrow. British Airways, the hub’s main user, opted to cancel all short-haul flights from the airport.

Heathrow’s night curfew was lifted in order to assist with alleviating the disruption. CFMU says that other airports in the UK – including London Gatwick and London Stansted – were less affected, typically suffering delays of 35-40min per flight.

CFMU has yet to release figures on the effect of yesterday’s disruption on European traffic as a whole.

Source: Flight International