looking at this drawing it looks like at any point on this lower green line one can start to go full thrust upward
looking at red line at which point could it happen it looks to steep going down
posts in this thread say that tu 154 needs time to full thrust it sinks for a while before it starts very gradually go up
on the other hand this tower which is supposed to see you on radar shoud see it long before that height over runway is close to 0
on this drawing at distance 2300 is 30m maybe 40m
thay said that they lost it from radar suddenly this would be the case with the red line