I agree with Yo767 that an overload of 3 tonnes on an A-340 should not make a world of a difference. 3000 kgs may sound a lot to some, but is not even a couple of percent of the take off weight of the 340, in my estimation.
All aeroplanes are designed to withstand a certain amount of abuse in line operations and that abuse is commonly a misrepresentation of the actual weight of the plane. Some other examples of abuse are a mis-trimmed take off, rotation at less than V-R, and fast or slow rotation.
The ‘Safety Speed’ for take off, the V-2, and its corresponding V-1 and V-R speeds have some safeties built into them. I do not know the exact amounts but they will be with the manufacturer or the certification authority, for sure.
With all engines operating, the surplus climb performance available on a twin engined airplane far exceeds the surplus climb performance available on the 3 and, especially 4 engined ones. That is why, with all engines operating, an overloaded A-320 managed to fly with about 10 tonnes error in the weight and correspondingly lesser speeds.
Now, I am not assuming or making presumptions that there was a gross miscalculation in the weight ex-JNB on this flight, but if the error is rumoured to be 3000 kgs, then IMHO it is not a significant amount to warrant such an incident.
As far as the ethics of dissecting the incident, well, this remains a column for ‘Rumours and News’, and under the guise of anonymity, one does rake issues that may not surface, especially in some parts of the world. The Middle East is certainly one of them. Most incidents and corrective actions are never publicized and forums like the PRUNE remain the best source of information. (Thanks, Danny.)
In the present case also, no one mentioned an incident, also in Emirates, when the crews miscalculated their take off speeds, not too long back.