Following on from Mutt's dissertation ... (he does have all the numbers at his fingertips, does he not ? - fine lad that he is) ...
The certification bits are built into the AFM and limit the landing weight to the relevant WAT limit - whether it be approach climb or landing climb is irrelevant. This is to ensure that the aircraft has a likelihood of being able to climb during the initial missed approach.
From the pilot's point of view, some of the things to consider are
(a) make sure that the actual weight does not exceed the WAT limited weight.
(b) in the event of an AEO missed approach, it is a good idea to get back to the approach configuration without too much delay to better allow for a possible engine failure - and the normal aircraft procedural techniques we use do just this. So, for the 737 for example, the missed approach procedure calls for the flap to be retracted to 15 and the gear retracted.
(c) in the event of a OEI approach, we don't normally use more than approach flap and, when the gear is extended, the aircraft performance margins become quite marginal and the missed approach becomes a far more manipulatively critical exercise.
(d) if you were of a mind to do a OEI approach and landing with more than approach flap ... then I think you had better have a pretty good reason... ie a pretty serious sort of runway length problem.
[ 05 September 2001: Message edited by: john_tullamarine ]