ATC Watcher writes:
What I personally think, is that van Zanten truly believed he had a take off clearance. Why is THE question.
I agree with ATC W. As to his question, it seems to me that when van Zanten, not long after his FO had requested both ATC and TO clearances, heard the tower advise "KLM 4805, you are cleared to the papa beacon...", he accepted it as clearance to take off. He was in a frame of mind to expect and to accept TO clearance, he was in a hurry, and so on and so forth. Stanley Stewart in Air Disasters points out that van Zanten was a senior training captain and lacked recent line flying practise. He was more used to simulator operations, where formalities such as acknowledging a specific clearance are often dispensed with in favour of drills and procedures.
It appears to me as nothing more than an eminently human error, an error that could be made by anyone of any nationality, but this particular error could not have been made at a worse time.
Flight Safety asks why van Zanten was so sure Pan Am had vacated the runway. Obviously (to me, at least) because van Zanten was convinced he had been given TO clearance, he was sure the runway was clear. Again, a very natural thought process (it seems to me). Incidentally, Stewart states that when van Zanten answered F/E Schreuder's query with an emphatic "Yes", the F/O also answered simultaneously in the affirmative. I can't verify this because I don't have the accident reports and transcripts in front of me but I'll check them.
I'm still unconvinced that better CRM would have prevented this accident. However, Forget, I'll check out those threads on cultural differences!
Rockhound