If you mean the Beaver at 10.40 - this accident happened during filming of 'Motherlode' (Charlton Heston/Kim Basinger/Nick Mancuso) - the accident was not scripted - but the film script was rewritten to include it in the story.
It is not that good a film but does have a nice little Flying sequence.
Edit to say - it is on youtube with the Beaver 'Arrival' at approx 22.00