Originally Posted by
john_tullamarine
The BCARs of the day had a quite different treatment, but the results were pretty much the same.
My imprecise recollection was that the BCARs had a requirement for 20kt accountability, although that may have been seen in the end AFM rather than the Design Standard specifically - until such time as I can dig through the archives, I am not able to resolve the problem.
Might you be able to cite those aspects of the BCAR which represented a "quite different treatment" to help reconcile the ageing memory ?
JT,
Without digging into very old boxes (even if I could find them), it goes something like this:
The FAA landing field length was the demonstrated length with Vref at 50', and that became 60% of the published landing field length. ie: Actual factored by 1.67.
The BCAR approach was to "account" for "pilot technique" by postulating a dispersion of threshold speed speed, up to +20, (and, if I recall correctly, height) but then only have a much smaller factor, so that the resulting published landing field length was very similar to the FAR 25 result. Certainly "close enough for Government work".
Don't quote me, but as I recall, the BCAR factor was something like 15%, all engines in the normal landing configuration.
Tootle pip!!