I am constantly trying to enter the temperature reported at the airport, but frequently getting "Invalid Entry".  Where (and when) exactly should you make this entry in the FMS ?

 

 

At what page and line are you entering temperature? You don't have to enter OAT of departure airport in FMC. This filed automatically as NGX has aspirated pitot tube. Also you don't need to enter temperature at destination in any field of FMC.

If it was on N1 limit page, then for manual entry of OAT you have use this fromat /XX. If you don't use slash, you'll enter assumed temerature for reduced takeoff thrust. This temperature must be equal or higher than airport OAT or you'll get INVALID ENTRY message.

My mistake.  I was trying to enter the OAT in the SEL position. 

 

Thanks for the response.