To keep it simple, let's ignore any headwind or tailwind effect. Consider a 747, or any other large jet airliner. The typical descent profile is a fixed speed from Mach number into IAS, then 250 kts below 10,000 feet. A heavy aircraft (eg freighter) landing at MLW will be closer to best L/D Ratio throughout the profile than a lighter aircraft, and so be gliding more efficiently.There is also more momentum to dissipate in deceleration. Both factors add up to more air miles in the descent for the heavier aircraft.
Neppy
