Most of what have been said for 744 apply to a340 as well as it is the regulation for 4-engines aircraft.
My company quite often trained in the sim., engine failure, dumping and return for landing, go-around in very short final, and second engine failure at power application.
No problem at max. landing weight, IF you do it correctly, and there is an escape path as your climb rate is very low. At max take-off weight or just after take-off, like already said,... rest in peace.
My 2 cents.