Monday, 11 March 2013

Air Traffic Control over Brockley: Geek-fest

Last Friday night I went to a public meeting in Deptford about the recently increase in early morning aircraft noise over the area. (The increases have been all day, but only the early morning flights have caused me disturbance.)

I loved all of the maps with flight paths plotted onto them and the facts that came out during the discussion. It was geekery of the highest order.

I arrived at the meeting ten minutes late so missed the introduction. However, my understanding from the evening is that the objectives of the current trial (which come to an end on 31st March) is to try and distribute the current aircraft noise more evenly across London. The man from BAA stated several times that there were no benefits accruing to Heathrow, in terms of increased numbers of flights or more revenue, from the changes being trialed.  Experiments to help benefit the community should be applauded; this one just seemed to go a little awry.

Why do planes fly over Brockley?
It is desirable for planes to land into the wind and 70% of the time the prevailing winds over London are westerly, meaning that aircraft fly in over the city to have a head wind on landing. The other 30% of the time planes arrive over Windsor, as is the case with our current cold snap.

The government also mandates that planes arriving at Heathrow must have a straight approach beginning ten miles from the airport. This means planes must have arrived on their final flight path by about Vauxhall.

What happens at the moment?
Image is from BAA. Brockley is difficult to spot on the map, but it is
almost exactly on the border between the inner and outer boxes.

There are sixteen early morning flights each day that arrive between 04:30 and 06:00. I was initially surprised it was so few, but one plane every five and a half minutes is a frequency where if one wakes you up – as they have done for me several times – there is little hope of getting back to sleep.

We were given the above map for a typical day at the moment. You can see that the planes form for their final approach in reasonably spread out way. Brockley gets some and other places the remainder. Under this regime I haven’t noticed aircraft noise being a problem. From the Brockley perspective I’m not sure why we needed a trial!

Inner and outer boxes
During the trial four boxes were drawn in the airspace over London and grouped into two pairs, the ‘inner’ and ‘outer’ boxes. During the trial air traffic control were told to avoid flying planes through the ‘inner’ or ‘outer’ boxes during a week on / week off (I think, it could have been two weeks on/off) regime. The idea being that those under the boxes would get some respite during their time off.

Based on the maps we were shown with the flight paths overlaid adherence to the scheme has been pretty good.

The consequence of the scheme (from the Brockley perspective) is that when the inner boxes were in operation the formation of the early morning flights centred over Brockley as they didn’t have many later chances to get into line before Vauxhall. It is the turning and banking of a plane that creates the most noise and this was happening with an increased frequency above us. The relatively even distribution that occurred before the boxes were introduced had disappeared. The increased early morning noise and it’s regularity is what has caused so much local ire.

Conversely when the outer boxes were in operation Brockley experienced much less noise as the formation of flights took place further east..

 Outer boxes in operation - all quiet in Brockley
No flights getting into formation over Brockley means relatively little noise. A small cross, marking Brockley, can just be seen just above the top left corner of the lower box.

Inner boxes in operation - noise for Brockley
Virtually all the flights for Heathrow form above Brockley resulting in higher levels of noise. A small cross, marking Brockley, can just be seen just above the top right corner of the lower box.

What next?
It was repeatedly stated during the evening that the current trial would come to and end on 31st March and guarantees were (almost) given that the scheme wouldn’t become permanent due to the opposition received.

It was slightly less clear if any future trials would be taking place. As there is, seemingly, no benefit to BAA it would be easy to think not. However, the catalyst for this trial must have come from somewhere, so it is conceivable that there will be future experiments. I’m sure something could be done to ensure a more even flight noise with greater thought and modeling.

Other tit-bits from the night
The more long term future was briefly touched on at one point. The gentleman from BAA said he saw three options. Firstly a third runway at Heathrow, second the building of a new hub airport or third the status quo would be maintained. Something I got the impression he thought was most likely.

Interestingly he said that if a new hub / Boris Island was built then Heathrow would close as London couldn’t sustain two hub airports. Not something I’d considered before.

It was also suggested an airport in the east would be a bad idea as planes were louder taking off than they were landing. An airport in the Thames estuary would mean that flights would be taking off over London 70% of the time. My uneducated view is that airport expansion needs to be either north of south of the city.

I knew Heathrow was the busiest airport in the world, but they fact it achieves that with just two runways is quite amazing. Frankfurt airport was briefly mentioned during the night. It has four runways and is the third busiest airport in Europe? If London had a four runway airport it would be likely that the flight cap would be 720,000 planes per year, up from Heathrow’s 480,000 now.


  1. Great blog. thanks

  2. Surely the "benefit to Heathrow" of such trials is to soften opposition to Heathrow expansion?

    I went to a meeting about airport expansion last night, one of the speakers was one of Boris' advisers. I am now convinced that the only solution is a new airport to the East.