Hi blade root, it´s kind of a policy - until they tried to recover an engine failure in such a situation i.e. in a simulator. There after they might change to the "exposure time" method - keeping the time, where an engine failure kills you - as short as possible. Going through the accident statistics engines fail quite often, when on high power settings. So keeping the time with high power as short as possible makes sense. At 35 to 40 KIAS you´re normally capable to fly away with only one donk running - and you reach that speed in a few seconds - compared to a CAT A profile when overweight...... When you start to talk to one of them - take the books and go on the CAT-A pages - its written down, when CAT A is recommended and allowed. When you are out of the parameters - its the pilots decision how to depart - and I stick to the exposure time method - giving only a few seconds of thrill... Would not fly with a pilot, if he insists on departing with a CAT A profile when overweight. Greetings Flying Bull