Stalling when climbing to cruise on autopilot

First, you're trying to get too much climb out of the aircraft. You can't expect it to climb at 3000FPM at fl250. You need to lower the climb rate when you hit 18,000 feet to around 1200FPM. When you're a few thousand feet from your target alt. you can reduce climb even more to 5-800FPM.

The reason trim is to max, is like I said, you're trying to get it to climb too much at the altitude you're at.

What's your target cruise altitude also?

I would agree but I climb very steeply at about 2500 fpm to around 37000 feet and I never get the stall warning and the pitch up attitude is not that big. 😉

I'm guessing on FPM because I don't know what he's trying to fly. It also depends on weight for climb rate. All the aircraft I fly don't get a 2500FPM rate of climb without burning idiotic amounts of fuel.

I agree with FEM and I'm sure that this rate of climb is whats causing the stall.

You see the rate of climb is NEVER constant. That's why I don't think the default jets are realistic because VS is the only mode of climbing, wheras in almost every real airliner, there would be a 'Speed' or 'IAS' mode that would allow the rate of climb to governed, not by a set rate of vertical speed but by the forward Indicated Airspeed.

So if this was set to 250kts in your example, then the plane may fly at 2500 at say 8 - 12,000 but at higher altitudes the rate of climb would be less, say 1,600 or 1,800 feet per minute in order to maintain the same indicated airspeed..

Best thing to do is try what we've sugested - when you take-off and engage the AP, set it to 1,800 instead of the setting you're using, then when you reach 18,000 reduce the V/S to 1,200 and see how that works.

😉

Folks, I just tested the reduction of rate of climb solution and that was definately my problem.

By watching the airspeed and the elevator trim roller, you can see when it starts to pitch up and struggle. I am now going through an excercise with all the aircraft I use (std 747, std 737, kulula md-80, ifdg a319, std learjet) and building a climb rate profile to use for each of them. I have now taken off from Johannesburg on a max weight 747 and taken it up to 39,000 - so my technique problem seems to be resolved.

The std documentation doesn't mention reduction of the rate at higher altitudes, but I suppose one should have forseen that. Maybe its in the ATP lessons and I missed it.

Having never controlled anything bigger than a C152 at nothing higher than 3,500 - these high altitude features take time to master.

Thanks for the advice. Now I can safely fly on VATSIM without disappearing after climb out and confusing the controllers!