TNX, Doze for the pages to show the displays.
For some reason, I wonder about the same "yellow" bars whether you're too fast, too slow, too whatever. Seems to me that slow or too steep or too high of an AoA or poor power setting should be red if low and green if at the desired condition ( up to a point) and then yellow or something to show above or below desired whatever. Then red is way outta line. In other words, keep everything green and you're as good as all the computers think you should be. And an arrow to show where you should be putting in controls. Of course, judgement and experience should take charge interpreting all the colors and raw data and colors, ya think?
'Bird and others here have flown the "indexer" doofers for AoA on approach, and they showed arrows to get to the desired value, and they were of a different color. Even we dumb fighter pilots could understand.
The early 70's lites had HUD displays that showed flight path ( FPM) WRT horizon and actual Earth. Trust me, a comfortable feeling coming off a CAT shot on a moonless night on the ocean. Ask any Navy Sluf or Hornet or Tomcat pilot.
In the AF447 accident, an inertial FPM would have shown the precise trajectory of the jet WRT the local level regardless of the air data. So no big deal. Keep the velocity vector on the horizon and then troubleshoot the air data problem.
Some jets had features to help "lead" course and vertical steering to the desired course, approach angle, whatever. We always looked at the raw data to ensure that Otto wasn't driving us into the mountain or the ocean.
I realize that installing and certifying a HUD for the commercial planes would be expensive. But I am here to tell you that it was one of the neatest things to have in low-vis approaches and when the air data went tits up due to iceing or otherwise. Always had the ADI for basic attitude and roll, but that FPM on the horizon line was of great comfort.
I am afraid that all the colors and such were of little value to those FO's on AF447, and some basic flying skills were also absent. CRM is another problem, as most here seem to agree.