Bank at any angle (up to 67deg) and you will maintain altitude.
Will it, really? Honest question.
Well, as long as you do not exceed the bank angle protection limitations, the aircraft will maintain altitude without pitch input from the pilot. Let's go a bit into detail:
If the pilot releases the stick at a bank angle greater than 33°, the bank angle reduces automatically to 33°. Up to 33° the system holds the roll attitude constant when the stick is at neutral.
If the pilot holds full lateral stick deflection, the bank angle will go to 67° and no farther.
But - if the pilot exceeds 33° he will have to make a pitch input, since automatic pitch trim is only active from 0-33°. So
you will not maintain altitude if you exceed 33° bank and the pilot does not increase the pitch input on the stick.
Furthermore, and just for some more info: If the bank angle exceeds 45° (while autopilot is active), the autopilot disconnects and the FD bars disappear. The FD bars return when the bank angle decreases to less than 40°.
So long,
DBate