It's not so much "needed" as it is a physical consequence.
The empty weight is the weight of the aircraft itself - without fuel, crew, passengers, cargo or weapons.
The absolute empty weight of an aircraft, cargo container etc.
Gross weight (Empty weight) of the F-14 is 43,735 lb.
The Gross Weight (Empty weight) of an X-15 is 14,600 lb.
Unusable fuel and undrainable oil.
The aircraft, un-useable fuel. No pax,pilots or baggage
The weight of an aircraft counteracts the lift produced by an aircraft. The heavier an aircraft weighs the greater the lift needed to get off the ground.
The A380-800's empty weight is 276,800 kg (610,000 lb), and the A380-800Freighter's empty weight is 252,200 kg (556,000 lb).
If the cg is not with in range the airplane will crash.
That depends on the weight and design of the aircraft.
DOW (Dry Operating Weight) in aviation refers to the weight of an aircraft when it is empty and without any fuel or payload. It includes the weight of the structure, systems, equipment, and furnishings of the aircraft. DOW is used to calculate the aircraft's performance, fuel calculations, and maximum payload capacity.
Lift, Drag, Thrust, and Weight. (Not counting Money)
The amount of thrust needed for takeoff depends on several factors, including the aircraft's weight, design, and environmental conditions like altitude and temperature. Generally, an aircraft requires thrust that exceeds its weight to become airborne, typically around 1.2 to 1.3 times the weight of the aircraft. For commercial jets, this often translates to tens of thousands of pounds of thrust, while smaller aircraft may require significantly less. Each aircraft's specifications provide detailed thrust requirements for safe takeoff.