Which weight measurement is used to determine if an aircraft can take off safely?

The maximum allowable gross weight is used to determine if an aircraft can take off safely because it represents the heaviest total weight at which the aircraft is certified for takeoff. This weight includes the aircraft's empty weight, usable fuel, passengers, baggage, and any cargo. Exceeding this weight can compromise the aircraft's performance during takeoff, flight, and landing, affecting factors such as the takeoff distance required, climb ability, and landing distances.

Understanding that the maximum allowable gross weight is a key parameter ensures that pilots and operators maintain safe operational limits. All other weight measurements, while important for other aspects of flight, do not provide the complete picture necessary for assessing takeoff safety. Empty weight is the weight of the aircraft without passengers, fuel, or cargo; usable fuel weight accounts only for the fuel on board; and weight minus baggage is still limited in scope and does not consider passengers or fuel. Thus, only the maximum allowable gross weight incorporates all aspects that can impact safe takeoff performance.