A friend of mine and I were just discussing a while earlier British Airways' decision to retire their A market (non ER) 777s, and he asked, couldn't they convert them to ERs instead?
Is this possible? If so, have any types of aircraft (757, 767, 777, etc) been converted after being manufactured into an ER configuration? And what modifications would that entail.
Also as an aside, I know that ER is NOT the same thing as ETOPS, but does ER have any effect on ETOPS? The reason I ask is that British Airways, for example, used all their A market 777s to the Middle East, and 777ERs to the US/Canada East Coast cities, although the distances to the middle East are actually longer. Was this choice because of the 777ERs are better equipped for overwater flights?