MFS, mate ... you, Mutt and I just HAVE to have a Guinness session ... the puns will fly thick and furious .....
My concern with amplification is that many of the PPRuNe fraternity use tech log as a resource ... what the specialists (in any field) take as a lemma, others might find totally confusing without some explanation to fill in the holes .... I know that I have learnt a great deal from several of the forums over the time that I have been a sandpit player .... and it is terribly frustrating if you only get half of the story ...
MaxAlt,
BFL gives a cheap and dirty quick way to get the RTOW figures done ... and, for convenience, is often referred to in documentation. By using BFL, you don't have to run as many calculations to figure the runway limit weight. It has no inherent technical advantage (Mutt might disagree as his mob use it for other reasons) other than general use and increased simplicity. On many, if not all occasions, a BFL-limited RTOW results in a slightly less than maximum RTOW for the runway and conditions on the day .... with wet or contaminated runways, or with obstacles and clearway, often the commercial needs dictate the use of an unbalanced takeoff.
Also, for many runways, the numbers may not be so critical as to warrant the additional number crunching to allow for the actual TODA, TORA, and ASDA figures.