Dear Glue Ball,
As part of our walk around, we are to check that all gear pins are removes and they should be in the cockpit. The one you're thinking of during pushback is the ground engineer's gear pin to disable nose wheel steeping for the tug. The Captain did the walk around in this instance, so he was responsible for checking that the main and nose wheel gera pins were removed and present in the cockpit. I hope this clarifies things for you.
[ 14 August 2001: Message edited by: busdriver25 ]
[ 14 August 2001: Message edited by: busdriver25 ]