Density Altitude
I was taught that density altitude is the altitude the aircraft thinks it is at and performs in accordance with. My understanding is that density altitude is affected by pressure, temperature and relative humidity.
In my experience, in most cases, aircraft takeoff and landing charts take into account actual pressure and temperature but not relative humidity.
In this day and age that information is readily avaliable and I would think would be easy to input if required, does anyone know why relative humidity is ignored? Is the effect on aircraft performance (both engine and airframe) so small thats its not worth taking into account or is reference to it just missing from the relevant legislation so ignored as matter of convenience?
Thanks in advance
Avanti