The department will next week publish a consultation document outlining alternatives to the five-year-old noise control regime that ends in March. The airline industry is expecting a backlash from environmental groups.
Under the present system, noisier aircraft such as the BAe 1-11 are banned from flying at night at Heathrow, Gatwick and Stansted, but even so-called 'super-quiet' aircraft are subject to restrictions. The system is based on the size of the 'noise footprint' made by aircraft on the ground below.
The new rules under consideration would give aircraft a points score based on noise output: this would be set against a total quota for the airport. Since some of the newer and quieter aircraft - the A320 Airbus and the BAe 146 - would score zero points, they could be flown or landed at night at will.
A similar regime has been in force at Manchester and Luton, with the quietest aircraft exempted from restrictions, and is seen by the industry as a success. Complaints about daytime flights at Luton outnumber those about night-time flights by six to one.
Bob Parker-Eaton, deputy managing director of Britannia Airways, the UK's second biggest operator, yesterday said the proposals would not add to night- time noise but nevertheless predicted a 'furore'. He added: 'There is a small minority of people whose sole aim in life is to close airports totally at night. It is an extreme point of view and it is not representative of reasonable people living around airports.'
There has been powerful lobbying by both sides. Several leading Conservative backbenchers and former Cabinet ministers have constituencies near the London airports. Airlines claim night flights are vital to the industry.
Last week a Civil Aviation Authority study found that 'very few' people living near airports were at risk of substantial sleep disturbance because of aircraft noise.
According to Britannia, failure to allow more night-time movements would bring increasing congestion, higher fares and a risk of losing business to Mediterranean airlines, which face fewer noise restrictions.
It says that night movements would be used 'almost entirely' for landings, which are much quieter than take-offs.
Evelyn Atlee, chairman of the Federation of Heathrow Anti-Noise Groups, said the advantage of the curfew was that it gave people a respite. 'Aircraft may be quieter but our members could not sustain more or less interminable night flying as well as daytime flying. People are not machines.'