Thanks big pistons forever for you comments and advice. I have to bow to your superior knowledge of the FARs and am not sure how 121 applies to Air Tanker Ops (maybe as guiding principles). However, dropping the load just after an engine failure is not the considered as the preferred option. If the performance considerations have been accurately and correctly considered and applied to the take off, dropping the load should not be necessary following an engine failure. However, in those circumstances it is considered sensible and is the approved procedure to at least consider the dropping the load.