A320 stabilizer position

[rudderrudderrat]

Hi pensador,

I think I understand what you are asking. Let's look at the aircraft with the Nose on the Left and the Tail on the Right.

The Centre of Gravity (C of G) is normally forward of the Centre of Lift (C of L) from the wing. Therefore this moment is counter clockwise. To balance the aircraft, the stabilizer must produce a clockwise moment and the leading edge of the elevator will point accordingly. In low speed flight with Flaps Full, it will point a long way down.

In normal high speed flight, let's assume the C of L hasn't moved much, therefore the stabilizer still has to produce the same clockwise moment. Because of the higher air speed, it only needs a smaller angle of attack to the airflow. Therefore the stabilizer will have been trimmed more clockwise to reduce it's angle of attack.

The stabilizer may move into your "upper dashes" position when flying close to VMO with high engine power setting.

Edit. The extra "upper" range on the stabilizer might be for the occasion when all the passengers huddle up in the rear of the aircraft, for some peculiar reason.