Everyone knows that every time we fly, we have a maximum weight limit for our luggage. It´s not arbitrary, but rather based on a number of reasons, ranging from safety to sustainability.
Incidentally, you may have been in the situation where you and other passengers were weighed before boarding. This is very exceptional (after all, imagine what it would be like to weigh every passenger, cargo, baggage, and crew on every flight!), but it does happen every so often, and as the European Union Aviation Safety Agency (EASA) confirms, it’s done as a measure of aircraft efficiency and safety There are standard measurements defined in the regulations for airline operations, which are reviewed periodically to ensure they follow current trends (i.e., the average weight in kilogrammes per person). The most recent study, from 2022, establishes that the average weight of a passenger with baggage is 84kg (pounds).
Before each flight, the captain receives extensive documentation on weight and cargo, including the number of passengers and type (a flight with adults only is not the same as one with a high percentage of children and infants, who of course carry less weight). With all this information in hand, he or she must either confirm it or request appropriate changes to the weight, cargo, and cargo balance.
And now here´s a closer look at each of the factors limiting weight carried on aircraft:
Maximum Take-off and Landing Weights
As you might imagine, each aircraft has different limitations. The load and weight of a short-haul aircraft such as an A320 are not the same as those of a long-haul aircraft such as the A350. There is something called MTOW (maximum take-off weight) and MLW (maximum landing weight). The aircraft’s structure itself, its fuel capacity, the performance of its engines, etc., are all adjusted to ensure safe flight.
Aircraft maneuverability is greater the lighter their weight and load; if you drive, you’ve seen how much easier it is to steer a car with just the driver than with a full load of passengers and luggage in the trunk. Consider long-haul flights, where fuel consumption is much higher, and where this load affects the aircraft’s stability. Obviously, all these factors are measured and controlled within a wide range to avoid even the slightest problem.
The Sustainability Factor
In addition to the top-priority safety factor, there´s also the matter of an aircraft’s efficiency and performance in terms of sustainability. As its weight increases, it will need more power for takeoff, landing, and cruising speed. The more kilos it weighs, the more litres of fuel it requires.
Efficiency also impacts the economy. With more weight and more fuel burned, flights are more expensive to operate. But in a world where airlines are seeking to reduce their carbon footprint, making flights cleaner is among our main objectives.
Other Factors Influencing Weight
Did you know that air density and temperature also affect how an airplane flies? Taking off or landing at an airport located high above sea level is not the same as landing at one near the coast. Thinner air (at high altitudes or temperatures) reduces power and lift capacity; therefore, in these cases more runway is needed to achieve the appropriate takeoff speed. In these cases, the aircraft’s weight needs to be reduced (fewer passengers, less luggage, or both).
Likewise, runway conditions are a variable that must be taken into account: a shorter runway length or its conditions (adverse weather factors such as ice, snow, or rain) also require adjustments to the aircraft’s weight.
Cargo Distribution to Ensure Aircraft Stability
Along with weight, how cargo is distributed within aircraft (i.e., its centre of gravity) is another factor that influences flight efficiency and safety. If cargo is not properly positioned, the aircraft’s center of gravity, essential for safe flight, could be compromised. The centre of gravity is the point at which the aircraft’s weight is concentrated. It cannot be displaced outside the defined range, either forward or aft. As fuel is consumed, the centre of gravity shifts forward during flight. In this regard, each airline has operators who follow strict protocols to properly distribute cargo, both commercial cargo and baggage in the lower cargo holds.