Originally Posted by Wayside

All Part 25 certified airplanes (including the 747) must be certified to land at their maximum gross takeoff weight. That doesn't mean there isn't a lower maximum landing weight but the manufacturer has demonstrated that the airplane is capable of landing at maximum takeoff weight. Fuel dumping is probably required to meet engine-out climb gradients rather than to lower landing weight, but that doesn't preclude one from dumping fuel in an emergency to minimize landing distance and perhaps get under maximum certified landing weight. It would be one less maintenance discrepancy to write up as well. But if the sh#% hits the fan, the aircraft theoretically could land at maximum gross takeoff weight as was demonstrated by the manufacturer.