Originally Posted by Skyjob
If manufacturer has a maximum structural takeoff weight for an aircraft by design but your operator is certified to use one 20 tonnes lower ($$$), would you go over the company imposed limit on that? Think of the same way with the 5 minute, your company has paid for 5 minutes, you do not get 10, although capable of it.
When you're on the ground doing load calculations, you are not in emergency situation and you have to obey all the dispatch limitations - 5-min T/O thrust (if you don't have the 10-min version), W&B, etc. But once you are in emergency situation (e.g. engine failure) the rules change and you don't have to oblige to them so strictly. I'm not saying you should push the engines for 10 minutes at TO thrust if you have engine failure as an SOP. Just focus on flying first and do it when you have time and the aircraft is stable in it's attitude and flight path (after turn for example) - even if thrust reduction to MCT is after 6 minutes instead of 5.
Since you bring up the W&B issue. What if you have an engine fire after takeoff that cannot be extinguished? Will you go to holding to burn enough fuel to get you below MLW or land ASAP?