Generally if your altimeter digits are in amber, you have an issue that needs correcting. If they're red, then that issue is seriously dangerous. The "tape" display is also an indication of vertical speed.
When we did the sim experiment, the digits were still amber when we began the recovery procedure - but it was very noticeable. Unwinding "steam gauge" style is definitely a secondary indicator that can be more easily picked up than read, but so is the colour change and the "tape" display.
@Lyman - no, the altimeter digit colour and tape display are not dependent on control law.
Last edited by DozyWannabe; 22nd February 2013 at 19:15.