Airbubba:
A lot of your questions are covered in the Operational Factors report here:
http://dms.ntsb.gov/public%2F55000%2...2F550741%2Epdf
Would the football be pegged at the bottom in this case or would path guidance not be displayed at all? It seems that the scale and 9999's were on the screen at some point from the panel questioning.
Look at page 57 of the report. They reproduced various situations in the sim and photographed what the displays look like. The un sequenced box situation shows half the football pegged at full scale high. I was trying to remember if it was even visible, I thought it wasn't, but apparently it is. Maybe I'm thinking that it's useless until active, so I ignore it. I think what you're asking is..... If the approach was incorrectly sequenced, but the path/football came active on the display, could he have used V/S to fly down it like you can do on an uncoupled ILS g/p ? The answer is no. The active waypoint in the box was KBHM. I'm not sure the box would even attempt to construct a g/p from a fix that isn't a runway.
The 'technique' of putting something lower than the MDA on the approach page of the FMC seems to be mentioned repeatedly in the pilot interviews. If this was done it would explain why the autopilot was still on below MDA in the accident.
Putting the MDA in the approach page tells the box when to disconnect the autopilot (50 ft below the MDA). Also, until you've entered the numbers, there are no cues in the box to allow you to activate the approach. I didn't see anything in the cvr that suggested they put anything other than 1200 in there. The autopilot would disconnect at 1150 ft IF they are on a captured path, in profile, on a properly sequenced approach. They weren't. Profile was armed but had nothing to capture and the plane was in vertical speed. The autopilot was never going to disconnect until someone manually disconnected it, which apparently he did, just before impact.