Originally Posted by
Gonzo
At the end of the day, whatever rankings are released, it doesn’t make the aircraft fly more or less accurately, or more or less quietly. Those of us actually working to reduce the impact on the environment, in all ways, by improving procedures, techniques and technology, don’t examine these rankings before we decide to go ahead with something, or re-examine a current aspect of operations.
Yes, that's a fair point.
Having said that, if any airport instigates a high-profile programme to measure and compare the environmental performance of its airlines (an objective that I fully support) then surely it has a duty to make the scheme work in a logical and transparent manner?
Instead, we have an implementation that fails woefully on both counts.
Leaving aside the ingenious way the final league table is manipulated, for example to propel BA shorthaul into first place when SAS, Delta and United actually performed better (what purpose could that possibly serve?), even some of the individual metrics are dodgy.
Take noise, for example. Heathrow uses the Quota Count values (based on ICAO noise certification - the higher the QC value, the noisier the aircraft). So far, so good - an average QC value per flight, or even per seat, would be a good parameter to use for that metric.
But rather than do that, Heathrow totals the QC values for all of an airline's movements, divides the sum by (number of flights x average seat size, i.e. total seats) and then divides the answer
again by the number of flights. It doesn't take a genius to work out that the best way to get a good score is simply to have a lot of flights, since the aircraft type involved carries far less weight. Or, to put it another way, if any two airlines at LHR were to merge, their combined Fly Quiet ranking would improve overnight without any change in their operational performance.
Sure enough, BA longhaul, which operated nearly a quarter of its flights with noisy B744s (Departure QC:4) and B772s (QC:2), gets ranked as second-best carrier for Quota Count whereas Air India, with all but a handful of its flights using B788s (QC:0.5), gets ranked Number 20.
Who thought that up?