Have you ever wondered how we know the final mass of the aircraft? It’s calculated in the Weight and Balance process by correcting aircraft empty mass with CREW, FUEL, CARGO, and PAX weights. While fuel, cargo, and even bags are carefully weighted at the airport, there is no such procedure for the people, so where do these numbers come from?
Holders of an Air Operators Certificate (AOC) are obliged by the Civil Aviation Authority* to establish a method for determining weights for passengers & crew including hand luggage. They have the following possibilities:
- All passengers including their hand baggage must be physically weighed before a flight.
- The standard weight for all passengers and their hand baggage can be established by the operator and it must be detailed in their exposition. This must be conducted in accordance with a survey program acceptable to the local CAA
- Applicable standard weights are to be used as specified by the local CAA or other Working Group contracted to provide accurate figures and responsible for conducting a study in accordance with the accepted survey program.
* CAA or other or other rule-making authority of a sovereign state or a group of sovereign states like EASA for the European Union.
It would be difficult and absurdly time-consuming to weigh each passenger of the commercial airline before each flight, so the majority of them use the standard masses for passengers.
They can be adjustable depending on:
- Type of aircraft (below 20 seats / 20 and more / over 30)
- Type of operation ( charter / regular flights)
- The season ( Winter / Summer)
- Departure/ Destination station (Freebird uses different weights for all flights from/to Gazipasa (GZP))
- Passenger class (it was proven in a survey that males traveling in business class weigh more than the average male, and female business travelers weigh less)
So the weights we use in the system are not based on some assumptions, they are carefully established. Moreover, they are periodically verified.
In Evionica Weight and Balance software, different weights models can be set up, so the Load Controller can switch to the correct one depending on circumstances. We use a system based on a gender breakdown, so for each model weights must be specified separately for Male/Female/Child/Infant.
The study to review the Standard Passenger Weights is performed by the responsible organization on behalf of CAA. The methodology is strictly regulated and it specifies for example the minimum number of participants in such a survey. The results are subjected to statistical analysis and the final report is published on a regular basis.
The results are further used to confirm whether the weights of passengers, hand luggage and checked luggage are still adequately reflected in the AIR OPS Regulation to meet the aircraft mass and balance requirements.
Considering the European Union region, the last study was performed by Lufthansa Consulting on behalf of EASA, and the final report was published this year on the 4th of October.
Looking at the results, we can see the recommended masses are slightly higher than the ones used in the current regulations but lower than the ones available in the recommendation given in 2008.
Based on the current study, the average passenger weight (including carry-on luggage) is 84 kg which is compliant with the current AIR OPS Regulations, therefore there is no need for an update.
It is also important to mention that the previous study from 2008-9 recommended the use of 88kg, while it resulted in figures quite similar to the current study. However, they used different ratio between male and female and finally more conservative approach.
If you fancy knowing how the masses are developed & what is the contribution of the aircraft type, season, low-cost operators, and other parameters used, the Final Report given by Lufthansa Consulting is available for anyone interested HERE.
What if something goes wrong?
From the perspective of the Weight and Balance solution provider, let’s analyze how the integrated system can contribute to a serious incident.
Quite recently, in July 2020 B737 operating for Tui Airline suffered problematic take-off due to the wrong mass calculation. It happened as the result of the system glitch, which classified as a child everyone who identified themselves as “Miss” while booking a ticket. 38 adult passengers were included on the final loadsheet as children, which resulted in a mass difference of about 1200 kg.
Considering the size of the aircraft and that even the proper mass was not above the aircraft limitation, the crew was able to take off safely, and in the final investigation, it was proven that safe operation was not compromised at any point.
When balancing the aircraft using Evionica Weight and Balance solution, most of the users do not need to pay attention to what weight system is used (it rarely requires adjustment for European flights), while the above text is proof that even such a small element (as it may appear on the surface) is in fact a subject of many studies and it is strictly regulated.