FLEXIBLE landing patterns being trialed at Heathrow could lead to round-the-clock aircraft noise, residents fear.
BAA will be running the first of two 'operational freedoms' trials for three months from November, to try to reduce the knock-on impact of delays, by utilising empty runways when services are delayed.
Currently, one runway is used for arrivals and one for departures, and every day residents have a 'respite period' with incoming planes switching airstrips at 3pm.
Under the new temporary regime, however, flights running just 10 minutes behind time, or going into a strong headwind, could use both strips to get the service back on schedule.
The trial will not lead to more planes in the skies - this remains capped at 480,000 flights annually.
The details were published over the weekend, just a month before the trial is due to start, and John Stewart, chairman of the HACAN residents' campaign group against aircraft noise, said: "We have been pushing for these details to be released for some time, and there were sharp intakes of breath when we finally got to see what was planned. It is much, much worse than we had expected.
"The criteria is so flexible, and it has got people worried because they are saying that if a flight is delayed by just ten minutes, they can switch runways.
"There could be a huge number of planes running out of sequence at any one time, and effectively destroy the respite period.
"I think there is a general lack of awareness about what these trials mean, and we will be staging a major publicity campaign later this month to alert people.
"It could improved services at Heathrow, but at the expense of residents' peace and quiet."
Hillingdon Council last week stated that it had largely been frozen out by BAA. and not been 'adequately informed' about the proposals.
Councillor Keith Burrows, cabinet member for planning and transportation, said: "Despite requesting to be involved at the earliest stage, this is the first time Hillingdon has been consulted with regards to BAA’s plans, which could have a significant impact on those living in the borough.
"However we will be working with BAA to ensure residents are properly consulted, and that the trial is undertaken in a transparent manner."
In response, Nigel Milton, BAA’s Director of Policy & Political Relations, said: "We have worked to involve local residents and other stakeholders through groups such as the Heathrow Airport Consultative Committee, which includes representatives from local authorities.
"We want to stress that the views of the local community are important to us. That is why we encourage residents to give us their feedback on the trial.
"The trial will enable us to test measures that could reduce the negative impact of disruptions on residents.
"It will not result in any additional flights and could mean fewer unscheduled night flights and less airbourne holding in the stacks."
Information leaflets have been dropped to more than 150,000 homes around the airport, and
Trials at Heathrow start on November 1, and run until the end of February 2012.
The second phase of the trial will take place between July 1 and September 30 2012.
If the two phases are deemed a success, residents in Heathrow Villages and other affected communities in West London will be consulted before any permanent procedure changes are signed off by the Government.
For more information about the trials, go to www.heathrowairport.com/noise