hi there
i had a question in the cyberexam about the relative humidity of the cabin. in the notes it says large passenger aircraft set to maintain 40-60%. however this is not the answer the exam is looking for. further study into this reveals that most passenger aircraft ideal is 23.45% and the normal range achieved is 10-16%
would it be safer to go for the lower ranges if this question is asked in an exam. between 10-20?
thank you
Narelle
The relative humidity inside the cabin of a pressurised airliner is always going to be very low. The reason for this is that the outside air temperature at cruise altitude is so low (typically around minus 50 degrees). So even if the outside air relative humidity is 100%, once it is heated for use in the cabin (around plus 20 degrees), the [b]relative[/b] humidity drops to just a few percent at best. The only solution is to add more water vapour to the air once it is heated, but water is heavy and so airlines aren't fond of carting massive quantities of it around the skies.
This is one of the reasons airline travel can give you sore eyes - the dry air. It is also why you should stay well hydrated on board.
