VS, FPA and FLCH

VS: choose a rate

FSS describes VS as a commanded vertical speed selected with the thumbwheel. Watch airspeed and thrust: the chosen rate alone does not ensure an energy balance.

FPA: choose a path angle

Set the cleared altitude, press FPA, and use the FPA selector to set the desired angle. FSS gives a selection range of −9.9° to +9.9°. Check the flight-path reference, selected altitude and aircraft response.

FLCH: choose a speed

In green FLCH, pitch controls the speed target and thrust affects the climb or descent rate. FSS says that selecting an altitude above the aircraft during a descent commands a climb; selecting one below the aircraft during a climb commands a descent. Check the selected altitude, thrust and actual response.

FMA transition

After a selection, read the active vertical FMA and target. Check that the actual pitch, trend and thrust agree with the intended outcome.

Altitude capture

FSS describes ASEL capture followed by ALT. Monitor the approach to the selected altitude and check that the expected transition actually occurs.

Record the mode, target and thrust state before changing anything. Then check how the aircraft responds to the new selection.

FSS says the flight-path reference appears automatically in FPA mode. You can also display it in another vertical mode with the FPR button on the display controller. The reference helps you monitor the path; it does not select FPA. FSS vertical modes ^[38].