02/12/2012

The Bise and two aborted landings

It cannot be easy landing an aircraft into a very strong wind. In the last week (at least) two pilots were sufficiently disturbed to have to abort, hit the gas and go around again.


20120211_EZY8480.jpgWe are always assured that aborted landings are not infrequent at Geneva airport, and the plots of all landing trajectories each day confirms this statement. Nevertheless, some seem to be less normal than others, so that the passengers probably have something to tell people afterwards.

One case yesterday, 11 February, would certainly have been interesting for the passengers: the landing of flight EZY8480 from London Gatwick. I noticed this particularly because the ARAG aircraft movements detection system thought that the aircraft had landed and then immediately taken off again at 9h24 pm (a touch and go) before actually landing at 9h43. My first thought was that the detection system program had a bug in it (you would not imagine how complicated is this program!), so I looked in detail at the recorded transponder data. Indeed, this did say that the aircraft had touched the ground then gone up again.

Being curious, I then looked at where the aircraft had actually touched the ground: the transponder messages give exact GPS coordinates. Surprisingly, this was actually half way along the very long runway: most unusual! I therefore suppose that the pilot realised his error: even though the runway is very long, he would have had to brake really hard in order not to go off the end.

As a second check, because sometimes the GPS coordinates can have a systematic error, I looked at where the aircraft actually finished once it finally came to a standstill. No problem: its position of latitude 46.23280 and longitude 6.10608 is (according to Google Earth), exactly at an easyJet mushroom parking bay.

Conclusion: the easyJet UK pilot might need to ask his Swiss fellow pilots for some advice (or else the Instrument Landing System or Traffic Controller guidance was not perfect).

Prior to that, on the morning of 7 February at about 9h50 am, I had noticed a very loud noise (typical of a noisy take-off) on the ARAG microphone in Vernier. After checking, it was evident that the aircraft was an incoming Aer Lingus flight EIN680 from Dublin, which was just over the noise station when the pilot decided that something was not quite right. The resulting climb thus sounded exactly like a takeoff over Vernier.

After an exhaustive check, I can find no reason for this aborted landing: transponder emissions from other aircraft do not suggest that any was still on or near the runway. I did find some ground transponder emissions of what look like non-flying vehicles: one calling itself MIKE (!) and the other YELLOW1: anyone know what these are?

Of course, as for any aborted landing, SkyGuide will have issued a report, but the chances of seeing that are probably rather less than of winning the lottery top prize:

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