Hi
Lyman,
Being that you asked,
May I see an artifact or image that shows an horizon? I'll wait.
TECHNICAL DATA
RANGE: pitch +/- 90 degrees
roll +/- 180 degrees
ACCURACY: +/- 0.5 degrees
• ATTITUDE according
to TSO C4c:
• ALTITUDE: according to TSO C10b (AS 8009A)
It is called a standby horizon (attitude/altitude) display that is located to the right of the Captain's FD, but to the left of the engine operating display. Below it is two other instruments, one being a clock. Probably, this is how the PNF determined the PF was going up instead of down, level the wings, etc., and later on, the altitude callouts he made as they descended rapidly It may be capable of displaying speed, but not in AF447's UAS situation.