Further to the above I quote the Boeing QRH, Performance in Flight-Text.
These values are actual distances and do not include the 1.67 regulatory factor. Therefore, they cannot be used to determine the dispatch required landing field length.
That would indicate that it applies everywhere not just Australia.
As Toronto was the dispatched destination those factors must apply. I would hate to try and argue to the ATSB or in a court of Law that they do not apply in all cases
other than an emergency. It is my belief that they do apply.
Quite frankly I find it a little strange that we factor thus when the aeroplane is perfectly serviceable but need no factoring, legally, when the aircraft is in a degraded state...that doesn't mean of course that good airmanship or company SOP don't require factoring in an emergency.
Don I agree that if they did it all perfectly, or even reasonably, they would have stopped in the LDA...but I remain sceptical that the approach was legal.
These are the sorts of accidents that, if anything was required at all, keep me in the QRH to ensure I am aware what is 1/. possible and 2/. legal.