Very easy to get bogged down in semantics here.
Generally, BFL refers to the aircraft AFM takeoff calculations, ie if TODR=ASDR then the operation is defined as BFL and, in this case, TODR refers to whichever case is limiting in the calculation.
I guess you can talk about the term in relation to the physical runway environs but it doesn't really make much sense to do so.
For whatever reason, BFL sometimes acquires some mystical significance .. which is not really justified. BFL calculations usually give the quickest RTOW calculation answer. However, in general, the BFL answer won't be the maximum RTOW for the situation. Therefore, if the operator so chooses (and the AFM provides the data - and not all do) the extra effort involved in running an unbalanced calc can be done.
It is NOT acceptable to juggle the speeds arbitrarily for longer runways unless sufficient calculations have been done to ensure that such variation is justified by formal calculation. In EACH AND EVERY case, the set of AFM calculations MUST be run to ensure that ALL the required certification things are addressed .. to do otherwise is to invite considerable embarrassment at the Enquiry and potential liability .. big time bad news.
Last edited by john_tullamarine; 17th January 2006 at 23:47.