Readers letters
I found the article in the June 2013 PE about aircraft noise very interesting, as I have seen this issue from both sides.
Firstly, I recently retired from Rolls-Royce in Derby after a total of 48 years service, of which my early years were spent in Preliminary Design, where we were involved in the initial design work on the nacelles of the RB211-524 (Boeing 747) and RB211-535 (Boeing 757) from the early 1970s. On both of these engine types, we were already concentrating on ways of reducing the noise signature, including the use of honeycomb structures in the intake, plus convoluted jet-pipes to mix the hot and cold exhaust air.
I was employed for the last 14 years in the Development department, where there has been a great deal of work carried out on development engines, to minimise the amount of noise emitted. Whenever a modification is made to an engine, particularly to the fan, but also aerodynamic changes to compressor and turbine blades and vanes and modifications to transmission components, it is tested rigorously, with some tests being specifically to assess the noise impact. Over the years, engine noise emissions have reduced significantly as a result of this and this was alluded to in your article, in discussing the reduction of noise footprints around airports.
The other side of the coin is that we live about four miles from East Midlands Airport, in the small town of Melbourne, which is literally under the flight path when aircraft approach from the west. Whilst we don't have an issue with this during "normal" hours (from about 6am to 11pm), EMA is apparently second only to Heathrow in the amount of freight which it handles, but this is achieved only by flights into and out of the airport continuously throughout the night, with aircraft regularly coming over at 10-15 minute intervals. I believe EMA is about the only airport in the UK to allow flights throughout the night. When we moved into our house in 1984, there was only the occasional holiday flight, which took off after about 5am, and these slowly increased in number as EMA became more popular. However, since DHL built a huge distribution depot at the airport, along with Royal Mail and TNT, night-time flights have increased to what I consider to be ridiculous proportions. They don't use the later, quieter, aircraft either. If aircraft approach from the west, the engines are throttled back and the noise disturbance per aircraft is usually relatively short, but if they take off westwards, they turn before they pass over our, but then we are "looking up the jet-pipe" for longer and, because the engines are on a high climb thrust setting, the noise is worse for longer. You can perhaps imagine how disturbing this can be.
I have often wondered what gives the operators, the airport authority and the local authority the right to allow peoples' nights to be disturbed to this extent. EMA have been challenged a number of times over the night flights and noise, but usually come up with arguments about the benefit to the local economy, etc. If John Stewart of Hacan feels that they suffer around Heathrow, I suggest he spends a week or two in Melbourne or Kegworth, to find out just how much of a nuisance night flying can be.
Geoff Medland, Melbourne, Derby
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