Originally Posted by Globaliser
No, I think you've still got it the other way around. The KLM thought it had takeoff clearance and began its takeoff roll. The Pan Am was just taxiing on the runway - it was nowhere near ready to take off.
Yup, the Clipper was taxing to the end of the runway, where it needed to do a 180 before being able to take off. The KLM had completed that procedure already and thought it had t/o clearance, which it did not.