Or,....in reply to the original question!
As has already been said, mrc is for max range.
For max endurance you fly at the best lift/drag speed (min clean speed?). On an Airbus the nearest displayed speed to min drag is green dot, but that is the single engine min drag speed. The managed holding speed is the correct one for two engines, but (on the A320 family) the two are very close on most engine/airframe combos. Some pilots hold at green dot speed, but the purists hold at the managed speed, which may be a few knots higher.
LRC, the speed which gives a specific range 1% less than max SR, is a commercial compromise between range and speed. For what it's worth, on the military fast jets 95% range speed is used for LRC rather than the civil 1%.
Sorry about the Airbus biased reply, but it's the only info I have.
In summary, for my simple mind, I use the following philosophy:
Normal Ops - LRC
Predicted low fuel at destination - MRC (cost index 0 on an FMC/FMGC). It will only give you 1% more range, but every little helps.
Predicted early at destination (airfield closed/ poor weather, etc) - max endurance (green dot-ish on an Airbus)
(edited to acknowledge that Bik made his post while I was writing mine)
Last edited by Bus14; 3rd June 2002 at 09:57.