In my airline days in the early eighties, my airline flew three 707-320C's. One of our flights departed, and for reasons not offered to ATC, asked to remain below 10,000 feet for the first 30 minutes of the flight. Quizzically, request approved. It came out much later that "someone" had forgotten to remove, and check removed, the nosegear down lock pin. Rather than dump fuel, and return, just to pull the pin, the flight engineer went down into the forward hold, then removed the pressure panel giving access to the nose gear, reached out, pulled the pin, and re-installed the pressure panel. With that, the nose gear was retraced, and the flight continued normally.