The airport’s noise action plan is at https://www.southamptonairport.com/media/5320/sial_noise_action_plan_2018_2023.pdf
Points to note:
- The airport only produces the averaged Lden (the one the WHO uses) noise contours for 2016 down to a 55 dB level. The 45 dB contour (the maximum level recommended by WHO) is not presented. The airport does not predict these levels for 2027 and 2037.
- A 10 dB increase is twice the loudness.
- The LAeq contours presented for 2021 and 2037 only go down to 54dB. The CAA produces contours for other airport e.g Heathrow down to 51 dB.
- The LAeq noise contours increasingly spread from 2016, to 2021 to 2037. The same would be expected of the Lden contours. This means that the 5,600 people (currently exposed to twice the levels of noise than is safe) will increase and he noise levels for those currently affected will increase to more dangerous levels.
- There is no guarantee of quieter planes in the future (similar promises made by London City Airport were proved not to be met). The airport’s own modelling is for more noise more widely spread.
- NATS data estimates that a single jet (of B737 size) is at least 63% noisier than a conventional turboprop on take-off at 1000ft. The airport plans to use more of this type of jet.
The airport promises a new breed of quieter aircraft. The Airbus A320neo (new engine option) is said to be 50% quieter than the old A320ceo. However this figure appears to refer to the noise experienced inside the aeroplane. As yet we have not found any verification of this figure and ‘50% quieter’ seems an odd phrase to use. This should mean that the A320 is twice as loud as the A320neo, which seems unlikely.
A comparison of EASA (European Air Safety Agency) aircraft noise figures show that the largest difference between the A320 and A320neo is at ‘the lateral certification point’ (Lateral EPNL). This gives a difference of 6 dB – meaning that the A320 is about 50% noisier than the A320neo at just this one point. An alternative way to say this (that the airlines and airports prefer not to do) is that the A320neo is only ‘33% quieter’. After all if you earned £200 each week and got a 50% rise you would earn £300, whereas if you got a 33% reduction in income from £300 you would get about £200.
At other noise reference points, the A320 is only 2.5 dB louder than the A320neo (the Approach EPNL) and 4 dB louder (the Flyover EPNL).