Vov - how do you explain going from your 'level flight' at 100m to 'losing' 40m in 3 secs? That's a fair rate of descent (800m/min average) - making something like 1600m/min peak - to generate suddenly! Then a most erratic rate - based on baro readings. Check also 40m/30m and 20m - rate of descent according to you doubles between 30 and 20? Have you ever tried flying an aeroplane like that? Tried plotting them?