Can someone answer this for me please. I understand that conventionally, aircraft have a horizontal stabilizer with elevator. Some aircraft have that replaced by a stabilator in which the whole wing pivots, but what is this on the MD80 series?
In the photos that I've found, it can clearly be seen that there are several movable surfaces.
In pictures 1 and 3 the front part of the wing is almost horizontal and the elevator raised.
In pictures 2 and 4 the front part is angled down - so it also pivots like stabilator.
But then as seen in pictures 5 and 6 we have the trim tabs, but they are split and operating in opposite directions - which appears to give a total of four separate movable surfaces on each side.
Also in pictures 5 and 6 - I thought that both sides were supposed to move together - but these are clearly operating differently.
What sort of system is this?