As pointed out at the University of York’s real time systems group meeting yesterday…
The Airbus A380 is the world’s largest passenger airline and it flies long distances. As such its human waste management systems have to handle a large volume of material.
Of course the material that ends up in the system was on the plane from the moment in took off but at the moment of takeoff the weight is distributed throughout the plane while the longer the flight continues the more of that weight gets concentrated in the waste management system.
More than that – the plane is getting lighter all the time – because it is burning fuel – so not only does the weight get shifted to a more confined region of the plane, it is relatively more important.
Hence the software on the A380 that manages the toilets is a safety critical system – and has to meet some quite exacting standards.