Hi Everyone: I keep seeing a message on my FMC in the NGX that says "TAI on or above 10 degrees" What does this mean? Thanks, Chris Catalano

Your wing and/or engine anti-ice is on. Which isn't required above 10°C. Best regards Tim Noebbe

TAI stands for Thermal Anti Ice.

Are the results of forgetting to use TAI when travelling through clouds/visible moisture below 10 degrees Celsius noticeable? Let's say i have been flying a long time through clouds at -24 degrees Celsius without TAI enabled. What is the consequence in real life ..what and when would one notice? and in the PMDG NGX?

Are the results of forgetting to use TAI when travelling through clouds/visible moisture below 10 degrees Celsius noticeable? Let's say i have been flying a long time through clouds at -24 degrees Celsius without TAI enabled. What is the consequence in real life ..what and when would one notice? and in the PMDG NGX?

Increased fuel burn. Also, if you work through the QRH anti-ice section, you'll see that you end up turning off the bleed air to the wings or limiting the thrust on an engine if the TAI is stuck on and TAT>10C. The engineers don't want hot air in those systems for some reason.

Increased fuel burn. Also, if you work through the QRH anti-ice section, you'll see that you end up turning off the bleed air to the wings or limiting the thrust on an engine if the TAI is stuck on and TAT>10C. The engineers don't want hot air in those systems for some reason.

thanks, but not sure if i understand your answer but then again, i may be missing the point on the topic of AI. The way i understand it, using TAI will raise the throttles and produce more thrust to compensate for the partial loss of energy dedicated for the AI. That is necessary to maintain the same forward speed of the aircraft. One must add a little thrust and thus burn more fuel for it. Using airconditioning in a car will burn more gasoline, The purpose of using AI is to prevent freezing of control surfaces on the wings, correct? My question is, when is that going to happen in real life when forgetting to use AI in extreme cold wheather conditions for instance.... and is that modelled in the PMDG NGX... frozen control surfaces as a result i mean.

thanks, but not sure if i understand your answer but then again, i may be missing the point on the topic of AI. The way i understand it, using TAI will raise the throttles and produce more thrust to compensate for the partial loss of energy dedicated for the AI. That is necessary to maintain the same forward speed of the aircraft. One must add a little thrust and thus burn more fuel for it. Using airconditioning in a car will burn more gasoline, The purpose of using AI is to prevent freezing of control surfaces on the wings, correct? My question is, when is that going to happen in real life when forgetting to use AI in extreme cold wheather conditions for instance.... and is that modelled in the PMDG NGX... frozen control surfaces as a result i mean.

You've engine anti-ice and wing anti-ice. In real life, you rarely use wing AI. Engine AI is used quite often. If you had icing and didn't protect the wings, your drag would increase and your stall speed would increase. If you didn't protect the engines, you could get fan blade icing and that could cause vibration, decreased engine efficiency, and I suppose in extreme cases engine damage and/or failure. I think I read that the performance issues are modeled but the visuals are not. Tabs is the one to ask for that, of course.

As far as I remember the NGX engines do not spool up a bit when using anti-ice, but that's a more technical thing. You basically have two different systems on the NGX. Anti-ice for the engine nacelles (TAI or engine anti-ice) and wing anti-ice. Engine anti-ice is used to prevent the buildup of ice, so you normally switch it on at temperatures below 10°C (TAT) and visible moisture. Wing anti-ice is used to melt ice away from the leading wing edges, so you switch it on when you actually see some ice accumulation and you switch it back off when your wings are clear (there are some Youtube videos where you can see the effect very nicely). Somewhere it was stated in this forum that ice effects are not modeled on the NGX, because the real aircraft has very efficient anti-ice systems and is not really prone to those effects. Control surfaces normally don't freeze inflight. You would perhaps apply anti-ice fluid before takeoff, but that works another way... Maximilian Gröber - edit: also see the post above - I was too slow...

I believe I read somewhere that wing anit-ice is for ground operations only. Is that correct? So you turn on wing anti-ice as you taxi over, assuming the plane has been sitting on the ground in icing conditions, and as you throttle up, the wing anti-ice automatically is switched off and you need not worry about it while in the air. I myself have yet to need anti-ice in the NGX. Been flying it around only in the hot summer, or now in Southern California and Hawai'i. No need for anti ice in Hawai'i :)

I believe I read somewhere that wing anit-ice is for ground operations only. Is that correct? So you turn on wing anti-ice as you taxi over, assuming the plane has been sitting on the ground in icing conditions, and as you throttle up, the wing anti-ice automatically is switched off and you need not worry about it while in the air.

That's not correct. While many planes are configured to have the wing AI switch off during takeoff, you still use it in the air. Boeing is very specific that you may not rely on wing AI as de-ice on the ground.

That's not correct. While many planes are configured to have the wing AI switch off during takeoff, you still use it in the air. Boeing is very specific that you may not rely on wing AI as de-ice on the ground.

Ok, thanks. I makes good sense to not rely on wing anti ice as the sole means to keep them clear of ice. That is what the green slop is for. Now then can I take this a bit further and ask when would be a good time to turn on wing anti-ice while in flight? Moisture and low temps I will turn on the engine anti ice on other planes, or when Active sky has a report of icing conditions at certain areas and altitudes, but for wing anti ice, aside from the PMDG JS41, I can't recall ever using it in FSX, nor do I have an idea when I should.

Now then can I take this a bit further and ask when would be a good time to turn on wing anti-ice while in flight?

In general, you should turn it on when you observe ice building up on the wings. The details are in FCOM v1, SP.16. Relevant quote (page SP 16.11): "Wing Anti-ice Operation - In-FlightIce accumulation on the flight deck window frames, windshield center post, or on the windshield wiper arm may be used as an indication of structural icing conditions and the need to turn on wing anti-ice.The wing anti-ice system may be used as a de-icer or anti-icer in flight only. The primary method is to use it as a de-icer by allowing ice to accumulate before turning wing anti-ice on. This procedure provides the cleanest airfoil surface, the least possible runback ice formation, and the least thrust and fuel penalty." There is lots more detail in the FCOM. -- Martin Boehme

Turboprop with boots is a different scenario that a hot wing. The last turboprop I flew, the procedure was to turn it on and leave it on. Not the same in a jet. RW, you're going to probably see some good ice on the windscreen before you're going to need wing ice. If it accumulates on the glass, you're picking it up pretty well, I'd say. Typically if you're taking of in light freezing rain or freezing drizzle, you'd want it on, otherwise, you're probably just looking out the window.

In general, you should turn it on when you observe ice building up on the wings. The details are in FCOM v1, SP.16. Relevant quote (page SP 16.11): "Wing Anti-ice Operation - In-FlightIce accumulation on the flight deck window frames, windshield center post, or on the windshield wiper arm may be used as an indication of structural icing conditions and the need to turn on wing anti-ice.The wing anti-ice system may be used as a de-icer or anti-icer in flight only. The primary method is to use it as a de-icer by allowing ice to accumulate before turning wing anti-ice on. This procedure provides the cleanest airfoil surface, the least possible runback ice formation, and the least thrust and fuel penalty." There is lots more detail in the FCOM. -- Martin Boehme

Turboprop with boots is a different scenario that a hot wing. The last turboprop I flew, the procedure was to turn it on and leave it on. Not the same in a jet. RW, you're going to probably see some good ice on the windscreen before you're going to need wing ice. If it accumulates on the glass, you're picking it up pretty well, I'd say. Typically if you're taking of in light freezing rain or freezing drizzle, you'd want it on, otherwise, you're probably just looking out the window.

Thanks you guys, great information. And I will of course consult the FCOM for more details. Cheers!