As you may still remember, toilets onboard were flushed by blue chemical in the past. Eg: B 747-200s, B 747 SPs etc.
These toilets are not very strong and in many times, it is hard to flush aways things. Therefore, it is not very hygienic.
From what I have heard, aircraft that go through the 'D' Check will have their 'Chemical Flush' toilets being converted into Vacuum Flush ones. Right?
Does anyone know what airlines still use the old system for their toilets on B 747s?
The Vacuum system is A LOT better.
Also, where are the flushed stuffs being stored? It is not very sensible to store them in a tank under the passenger deck as the temperature there is too low.
Can anyone give me the answer? Thanks a lot!