Systems built into the landing gear do exist, but they're not very common. There are also ground-based systems (i.e., scale-on-a-cart for each wheel). https://

Systems built into the landing gear do exist, but they're not very common. There are also ground-based systems (i.e., scale-on-a-cart for each wheel). https://aviation.stackexchange.com/questions/16307/how-does-a-commercial-airliner-measure-its-weight-mass https://aviation.stackexchange.com/questions/16307/how-does-...