I think all planes will do this. If you take off and immediatly switch from auto takeoff to auto climb you will head down, sometimes into the ground.
The reason is "auto-climb" is not really auto-climb. It is auto speed control. You can set it to any speed you want, it defaults to the general best climb speed, usually around 165-175. But you can change it to 225 or 250 if you want, which I almost always do if there's a red dar bar in the same sector I am in. That way I may be climbing more slowly in ROC, but I have enough speed to manouver if jumped. However if you aren't going 225 when you engage it the plane will point down and accelerate to 225 before auto raising the nose to maintain the 225 setting.
It also works as "auto-descend". If you want to descend at a set speed, engage "auto-climb" and cut your throttle. The plane will maintain whatever speed you set by varying your descent angle. Where this is most useful is when you've lost an engine or are very low on fuel;. Your auto-climb speed also happens to be your best glide speed (generally). Use auto-climb (actually it's auto-speed) to maintain the best glide speed/angle for maximum glide distance.
The command to change it is .speed xxx where xxx is the speed you want to maintain. Example: .speed 225 .
