Who is to blame?
This is the second tailstrike accident to occur with a 100 tonne error in the take off performance, the other being a Singapore Airlines 747 in 2001 in Aukland. Similar incidents in more than just the tail strike aspect. The time zone differences were about the same, both Singapore and Emirates have similar working practices and the pilots will have been similarly fatigued.
The captain stated he only had three and a half hours sleep in the previous 24. This is typical of trying to get rest outside your normal circadian pattern and 99 hours flown in the previous 28 days is a very hard working pattern - far more than allowed under the two regulatory authorities I have worked within.
It's all good and well saying the pilots should have noticed this error earlier on the take off roll, but with the grinding chronic fatigue that comes from such a long haul lifestyle and probably combined with the acute fatigue which comes from such a long trip, the ability to notice such errors quickly is going to be markedly impaired.
It's interesting that Emirates required the pilots to resign as soon as they got back to Dubai. It's indicative of the concern the airline had that the incident may have been related to their Flight Time Limitations - which in Duabi are set by a regulatory authority which seems to be answerable to the airline and not the other way round. There has been enough written on this website in the past about Emirates duty times.
But what about the aircraft? A system which allows such a gross error to be inserted is at fault as well. The designers may think that such errors are hard to make, but this is the second in very similar circumstances. And don't forget the MK 747 Classic freighter which fatally crashed in Halifax in 2004 when the fatigued crew used the previous much lighter flight's data and went off the end of the runway. Unless they have experienced the fatigue of continued long haul operations, it is very hard for them to understand how such errors can be made and then which escape the error traps.
I used to fly 747-400s which had weight and balance computers. The system measured the pressure in the oloes and told the crew how much the aircraft weighed and where the c of g was. I was amazed that there was no system which correlated the speeds input by the crew with what the aircraft thought the speed should be be based on it's own weight measurement. It's only a simple piece of software.
So don't be too quick to blame the crew as there are many factors which led to this error. I too have seen the 100 tonne error made. In this case it was trapped early by the mechanism set up to catch such mistakes. I'm sure it has been made many more times - and been caught. The fact it occaisionally gets through system should be ringing alarm bells and probing investigation deeper than the very typical pillorying of the pilots.