tag on FMC

[Zachiii 0]

On my Flight Management Computer on occasion I get the following message "TAI on above 10 degrees."

 

What does that mean?

 

 

Also, at altitude my 737 always shows much warmer air temp that wind aloft forecast.

 

Any fix?

 

 

Thanks,

[downscc 1,327]

TAI on above 10C is an advisory that you have thermal anti ice protection turned on when the surfaces are above the required temperature.

 

The indicated temperature you are looking at is not the ambient outside air temperature but the actual temperature of the wing surface that is heated due to high airspeed and compressive effects (total air temperature TAT). This is actually more complex than it sounds LOL, here is a good brief: https://en.wikipedia.org/wiki/Total_air_temperature

[scandinavian13 5,192]

On my Flight Management Computer on occasion I get the following message "TAI on above 10 degrees."

 

What does that mean?

 

This means that you have anti-ice on when it's not required.

 

 

Also, at altitude my 737 always shows much warmer air temp that wind aloft forecast.

 

Any fix?

 

No fix because there's nothing wrong.

 

TAT is the true air temperature, which is affected by kinetic energy, which you have a lot of. The nose temperature of Concorde was above 200 Celsius. Meanwhile, the external temperature was below 0 (SAT - static air temperature).

[Zachiii 0]

Many, many thanks.

 

I feel better and a little smarter!

 

 

zach

[soerennielsen 35]

Sorry to correct you Kyle,

 

But, Maximum Operating Temperature (TMO) for the nose of the concorde was 127 celsius.

[scandinavian13 5,192]

Sorry to correct you Kyle,

 

But, Maximum Operating Temperature (TMO) for the nose of the concorde was 127 celsius.

 

True - knew I should've looked that up. More than 200 F, though, admittedly, I was trying to recall what I saw on that tip temp gauge, which displays in C, so...bad on me for not taking the time to look it up.

 

Still: a result of the effect of speed on TAT, and how it varies from SAT.

 

EDIT: 15 seconds on Google and I find a nice picture where the gauge even states: "TMO = 127 C"

RTFM Kyle...RTFM...