DJ777:
Wx deviations ?
Precise calculations using the last ACARS position message coordinates (as reported by BEA) show that the crosstrack error (XTK) was 2.95 nm left of UN873 centerline.
Examination of the messages reception times and precedence, assuming equal transmission times, exclude the possibility that the a/c was on track and on course when the AP disconnected.
This can neither be explained by assuming they were using a tactical route offset since these offsets are only allowed right of track.
Hence, I tend to believe there is a strong clue that weather deviations had been in progress when the first cockpit alarms occured.
Hi DJ777,
If you were using Google-earth for the calculation, as I did two weeks ago, you will notice that the flight plan "flat line" and the flight plan "at altitude (35,000 ft or 10,670 m)" is somewhat slightly moving to the west, making a 2.68 NM separation from the "flight plan center line". The last positional report (2.98, -30.59) is taken from the aircraft GPS which also may be rounded for ACARS sendings and could be affected by another error margin added to GPS one. The other positions (0200, 0150, 0140) that I reported are extracted from BEA reconstructed flight plan as the real coordinates are still waiting to be published yet.
Looking at the map I did from the Meteosat-9 image, which was part of the preliminary documents (6 June) from Météo France in BEA site, one may notice that the 0210 event is taking place exactly where the top of the CB was the coldest at 0208 (then the highest) but nobody can say for sure how it was pictured by the radar below @ FL350. From the last BEA report, it is described that this image was the situation at 0208 instead of 0215 because the area pictured was scanned at this time:
One may look also at the CB animations made by Météo-France and notice that before departure time and during meteo briefing, this CB wasn't formed:
- Les conditions météo dans la ZCIT vues par Meteosat
(infrarouge, du 30 mai 0h TU au 4 juin 0h TU);
=> Hourly meteo map animation:30.05.09, 00.00 to 04.06.09, 00.00:
http://www.bea.aero/fr/enquetes/vol....062009.p12.avi
- Zoom du 1er juin de 0h à 3h45 TU:
=> 1/4 hour meteo map animation: 01.06.09, 00.00 to 01.06.09, 03.45:
http://www.bea.aero/fr/enquetes/vol.....03h45.p14.avi
S~
Olivier