Originally Posted by
aCavalierInCoach
odd... is this an max gross landing weight issue or something else?
Often times yes. Planes can be limited by weight in many dimensions. Maximum zero fuel weight, ramp weight, taxi weight, takeoff weight, landing weight. If the aircraft in this scenario had a high payload and was fueled for a longer flight and then subsequently switched to a shorter flight, the issue very well could be the possibility of exceeding the maximum landing weight. Many transport category airplanes are certified to takeoff at one weight but must (under normal operations) ensure they land at a weight which is often times thousands of pounds lighter than the maximum certified takeoff weight.
Say a plane can take off at a maximum weight of 200,000 lbs but may only weight 150,000 lbs for landing. Now imagine this plane is scheduled to operate a flight where the fuel burn will be 20,000 lbs. Even though the plane is capable of taking off at 200,000 lbs, in this scenario the airplane may only take off at 170,000 lbs (maximum landing weight + fuel burn).