Noisy skies

SIR, — I note that your Editorial Comment last week made reference to reclaiming our airspace from the increasing noise nuisance from helicopters. The basic problem here is that helicopters are allowed by the Civil Aviation Authority (CAA) to fly within

SIR, - I note that your Editorial Comment last week made reference to reclaiming "our" airspace from the increasing noise nuisance from helicopters.

The basic problem here is that helicopters are allowed by the Civil Aviation Authority (CAA) to fly within 500 feet of persons, structures etc. For larger conurbations this distance is revised upwards to 1,000 feet. However, some of the larger helicopters can have two engines of 500-800 horsepower each - ie hefty - and the noise from helicopters is judged to be 10-15 decibels more annoying than from other sources that have similar noise-meter readings. This is because the helicopter rotor operates at low frequency and generates what is known as "impulsive" noise - ie the "thwap-thwap" noise. Noise issues from helicopters can be reported to the Director General, CAA, 45-59 Kingsway, London WC2B 6TE, although hitherto they have not been that interested in noise issues from aviation.

Locally complaints can be made to Luton Airport Environmental section (noise@ltn.aero), although Luton Airport states that not all of the helicopter nuisance is down to them. However, Luton Airport are responsible for routing overflying helicopters through local airspace.

The CAA have asked the Department of the Environment (DEFRA) to produce a report on helicopter noise issues, but all this seems to have achieved is a recommendation that more study and a central complaints database is required. For those interested in this report, the DEFRA contact is a Mr Ian Sherlock, DEFRA, Nobel House, 17 Smith Square, London, SW1P 3JR, and the report is DEFRA NANR235 Project report.pdf

Conclusion - several Government and regulatory bodies involved but not much actual progress.

COLIN WEAVER,

Tufnells Way, Harpenden.