Looking over the wonderful Tutorial #2 I've found this on page 33, second paragraph:

Since we’re flying an airplane with aspirated TAT probes, verifythat “TO” for takeoff appears on the upper engine DU.

I'm guessing this is a mistake and that the sentence meant to continue about having the correct temperature on upper DU? Or is there a relation between the outside temperature and the FCC showing the maximum thrust sooner then on a non-aspirated probe?In any case, I'm wondering, if the NGX indeed simulates an aspirated TAT probe, should it not have a TAT TEST pushbutton on the Ice panel below the Probe Heat buttons?

Eric, no - the TO mode is only shown with aspirated TAT probes. I don't know the exact reason why but it's mentioned in the normal procedures.The TAT TEST button wasn't modelled - will ask about doing it for SP2.

Eric, no - the TO mode is only shown with aspirated TAT probes. I don't know the exact reason why but it's mentioned in the normal procedures.The TAT TEST button wasn't modelled - will ask about doing it for SP2.

oh when is sp2 coming out :)

The aspirated tat is the only one "authorized" to supply direct OAT info to the FMC, because when APU bleed is on the aspiration is working on the probe this giving good temp readings. This is not the case for the unaspirated probe, in that case the /OAT field in the N1 page is empty (this removing a needed value for N1 limit calculation)The NGX simulates the aspirated one because of the presence of the OAT automatically detected in the N1 limit page.

The NGX simulates the aspirated one because of the presence of the OAT automatically detected in the N1 limit page.

Wonderful information Andrea. Thanks.

Eric, no - the TO mode is only shown with aspirated TAT probes. I don't know the exact reason why but it's mentioned in the normal procedures.

Very interesting. It makes sense not showing the Thrust Limit without a known OAT either from Aspirated probes or from OAT entered in FMC. As for the TAT test, I wasn't being a smartass here :) As soon as I heard "aspirated probes" I googled it and found that is the way to recognize if you have one or the other. Until then I had no idea. Thanks.