This has soemthign to do with weather right? Its an entry in the md-80 fmc, what does this mean?

>This has soemthign to do with weather right? Its an entry in>the md-80 fmc, what does this mean?+/- temperature deviation from ISA temperature (15 C, 59 F)ISA = International Standard Atmospherehttp://en.wikipedia.org/wiki/International...dard_AtmosphereMarco

I haven't seen the FMC, but it's probably a field for the temperature deviation from the International Standard Atmosphere (ISA).ISA at sea level is, what, 15 degrees.So if it's actually 20 degrees, the deviation is 5 degrees.-Bryan

please note the entry into the FMS might be the ISA Dev at cruise altitude and not at sea level.

Thanks for the info.