Residents living under the flight path suffered with extra flights at unsocial hours this week following the introduction of a new air traffic control tower at Heathrow Airport.

The switchover to the new tower has been labelled "the biggest change in 50 years to Air Traffic Control at the world's busiest international airport" by Heathrow's owners, BAA.

The move from the old 39-metre high tower that opened in 1955, to the new 87-metre high landmark that was built in preparation for Terminal 5, happened at 2am on Saturday (April 21) morning - the airport's quietest time.

BAA had anticipated delays and more night flights than usual as a result of the move and the number of flights was reduced to ease traffic for controllers as they familiarised themselves with the new systems.

However, a BAA spokesman said the effects of the switchover went better than anticipated. He said from Saturday to Monday there were no extra night flights after 11.30pm and there had been seven flights, a relatively low number, inside the night flights window (between 5am-6am) over the same three days.

"It has gone very well. We have had a few extra phone calls to our noise complaints but nothing too significant," he said.

With up to 90 arrivals and departures an hour every day at the airport (a total of 477,000 flights in 2006), the switch to the new system has been a challenge for Heathrow's 60 air traffic controllers.