John,
points agreed.
One however assumes that the data is valid from the start, and that raises issues.
when it can be indicated that the line up was correct, wind, temp weight etc were valid, and the data shows gross errors in outcome, the veracity of the performance data becomes an issue.
when the manufacturer indicates the basis of performance is on methodology physically not allowed on the aircraft in operation, then one should be allowed to be skeptical. Particularly when no allowance is made for actual method of takeoff being totally diferent to that from which the performance figures are derived.
The problem I see is that over the top of basic errors are the factors you indicate, that certainly don't help matters further.
As to the smoking evidence, there are cases that have been put down to pilot error where either takeoff performance was marginal engine out, or the crew rejected and overran which are consistent with this topic.
The truth is out there, at 87% TODA.... watch fat albert taxi past.
