Part of the problem is they got into this mess because they were behind the airplane and had been behind it for a while. That means less time to do your normal procedures putting you further behind. That raises stress and causes mistakes. That cycle feeds back on itself making everything worse.
They'd have needed the mental bandwidth to notice on the EICAS display that the spoilers weren't deploying to even know to manually trigger them. Given how far behind they were noticing that would be highly unlikely. Under high stress you revert to your training or habits and manual spoiler deployment is just not something you need to do.
Their bank angle (for lack of a better term) was probably not enough to notice unless they had the mental bandwidth to pay close attention.
This is a common thing in these sorts of accidents: if you have the mental bandwidth to deal with these problems you'd have been properly setting yourself up for landing 30 minutes before you started and you wouldn't be in this mess to begin with.
This also represents a safety margin during normal flights: If everything is done by-the-book and going well then you are calm, collected, and you have the mental resources available to do quick instrument scans after touching down and potentially notice spoilers did not deploy - and you have the extra runway to account for the few seconds of delay it takes to notice then manually deploy them.
They'd have needed the mental bandwidth to notice on the EICAS display that the spoilers weren't deploying to even know to manually trigger them. Given how far behind they were noticing that would be highly unlikely. Under high stress you revert to your training or habits and manual spoiler deployment is just not something you need to do.
Their bank angle (for lack of a better term) was probably not enough to notice unless they had the mental bandwidth to pay close attention.
This is a common thing in these sorts of accidents: if you have the mental bandwidth to deal with these problems you'd have been properly setting yourself up for landing 30 minutes before you started and you wouldn't be in this mess to begin with.
This also represents a safety margin during normal flights: If everything is done by-the-book and going well then you are calm, collected, and you have the mental resources available to do quick instrument scans after touching down and potentially notice spoilers did not deploy - and you have the extra runway to account for the few seconds of delay it takes to notice then manually deploy them.