In the Olden Days (2005), Manston’s radar wasn’t good enough to tell them exactly where their planes were. They couldn’t tell the exact height because they only had Primary Surveillance Radar.
In the Modern Age (2009) they also have Secondary Surveillance Radar (they buy a feed from the MoD) so they can now tell the height of planes as they pass over Herne Bay. And elsewhere, presumably.
But they don’t record it.
This is perplexing me. Given the aviation industry’s healthy obsession with safety statistics and analysis, I would have thought that recording the actual position, speed and direction of all aircraft within detectable range of any airport would be encouraged to the point of compulsion.
This begs a question: when someone (like me) complains to KIA about low, noisy, off-route planes (as I have), how can they possibly be so certain that the plane was at an appropriate height, given that they have no record of it?
Another question: for a presumably modest outlay, Infratil would be able to to publish clear, accurate information about flight patterns, like this example from Luton Airport. How can they resist? It's a very effective way of letting everyone know exactly what's happening.
Oops. Did I just answer my own question?