[Madelaine Amee]

Originally Posted by B767drvr

Madelaine,

I'll try to be brief and keep it simple:

On a previous flight with the aircraft established in a descent, Lubitz reset the altitude window to 100' or near 100', but later changed it to the correctly assigned altitude. When the captain returned to the cockpit, he would have ABSOLUTELY NO IDEA the incorrect altitude was briefly entered in the altitude window. There is no instrument or display in the cockpit which stores/displays previously entered altitude entries. The aircraft remained in a constant descent (as it's designed to) while Lubitz changed the altitude setting so no one in the cabin, including flight attendants, would have any idea anything was amiss.

The only way any of this was discovered was by analyzing the individual flight data recorders of all tails Lubitz flew recently. The flight data recorders record some (approximately) 1,800 different inputs (nearly all of which are not visible to the pilots - exact control positions, temperatures and pressures of multiple systems).

Even so, there is no specific prohibition that I'm aware of against setting sea level momentarily. Some might argue it would aid in their descent planning to see the newly computed "end of descent" point visually depicted in relation to the airfield.

(Just a gentle caution against prematurely assigning blame where it's not warranted.)

Thank you for your very condescending account of what happens during flight. I'll keep this in mind before I venture onto this site again. But, it's always good to have an expert on hand to put one right when needed.