Of course it doesn't work that way in practice.

Person 1 looks and says, "hmm, looks good, besides, if I'm wrong, #2 will
catch it."
Person 2 looks and says, "well I'm in a hurry, I'm sure #1 caught anything,
besides, that's why #3 is there."
Person 3 looks and says, "well, I don't want to be the guy that calls out #1
and #2 for being wrong, so I won't say anything. I'm sure if this was
really a problem, they'd have caught it."

Adding people like this does not necessarily make things any safer and in
fact can make things less safe.

The way to properly due this is to focus on failsafe procedures. For one,
an interlock that doesn't permit the clock to go past X time unless the door
is registered as closed (and I'd be surprised if they don't have this). The
people are mostly a feel-good measure.

Think about when you fly. The flight attendants are told to check the doors.
They don't have all 3 or 5 or whatever check every door. And for the main
loading door, they have a procedure to make sure the door is locked and the
slide enabled.

When's the last time you heard of a door on an airliner not being sealed
properly?



"bob haller" wrote in message
...

- Show quoted text -

Well one person having a off day can easily miss something

Two people make it less likely, but 2 people can still have a off day.

Hopefully 3 people dont ALL have a brain freeze.

But when it comes to the hatch its likely a great idea.........

hey nasa cut the number of workers from 3 to 2.

3 flights later the orbiter depressurized on launch

not a worthwhile risk!



--
Greg Moore
Ask me about lily, an RPI based CMC.