Can't speak to the NG but for the Classics .. reconfiguring to land is straight forward .. but the above comments give the secret away - one needs to have practised the manoeuvre in the sim a few times to see the problems and get on top of them.
Problems include
(a) not being aware of the problem in the first place ie failing to recognise the failure (and that is an easy trap if you still are bleeding speed back to a stable final configuration) .. which sets you up for a (fairly rapidly) energy decaying situation prior to the obvious becoming blindingly so
(b) you don't have all day. If you aren't onto it very quickly you will find yourself in a difficult energy predicament fairly quickly and a small problem becomes a big one.
MORAL engine instrument scan needs to be integrated into the overall scan on final .. a lot of people take a while to learn this lesson.
However, several practice approaches in the sim and it becomes a bit of a doddle.