I recently wanted to fly a trans-atlantic flight from Amsterdam to New York in the Posky Boeing 767-300, when I encountered this problem.
At first everything went as expected but when I reached FL200 the airspeed began to decline rappidly. I the lowered the Vertical Speed and that had some effect the airspeed began to climb again, but after a couple of minutes when the airspeed dropped again. Again I lowered the VS, but this time the airspeed was still going down. Even when I lowered the VS to zero, the airspeed was still going down. So I disengaged the AP and tried to get the plane climbing again myself, this had no effect, so I ended up in a rather spectacular spin above the North Sea. I had a hard time leveling the plane again (and I think some passengers are gonna file some serious complaints).
Can anybody tell me what the problem is or could be, and more important how this can be fixed ? Or is it just the design of the 767 to climb very slow ?
