Engin Anti-Ice Usage

[GVJeff]

I am curious what other operators use as far as anti-icing criteria is concerned. Do you use SAT or TAT? The Gulfstream manual also refers to FAT. Does anyone know what that is? FAT??? In 34 years flying Gulfstreams I have never heard of that.

I am eager to hear others opinions.

Jeff

 

[Archie Bunker]

The Gulfstream manual also refers to FAT. Does anyone know what that is? FAT??? In 34 years flying Gulfstreams I have never heard of that.

If memory serves me correctly, FAT = Free Air Temperature........I think it's a fancy way of saying OAT (outside air temp). I'm pretty sure that in my past I used to fly an aircraft with a FAT gauge, but for the life of me....I have no clue which one it was.

 

[AirBadger]

If I had a FAT gauge, it would be in the red.

 

[caseyd]

I am curious what other operators use as far as anti-icing criteria is concerned. Do you use SAT or TAT? The Gulfstream manual also refers to FAT. Does anyone know what that is? FAT??? In 34 years flying Gulfstreams I have never heard of that.

I am eager to hear others opinions.

Jeff

On ground - ON in visible moisture (visibility < 1mi., rain, snow) or standing water/snow/slush on the ramp with OAT (SAT) of 10C or less.
In flight - ON with visible moisture and temp of 10 TAT or less.

OFF when TAT is 40 or colder in climb or cruise regardless of conditions. (ON regardless of temp in descent when visible moisture is present.)

 

[Falcon Jet 1]

On ground - ON in visible moisture (visibility < 1mi., rain, snow) or standing water/snow/slush on the ramp with OAT (SAT) of 10C or less.
In flight - ON with visible moisture and temp of 10 TAT or less.

OFF when TAT is 40 or colder in climb or cruise regardless of conditions. (ON regardless of temp in descent when visible moisture is present.)

agree with everyting but the off should be 40 SAT not TAT

 

[capt_zman]

Been flying Gulfstreams for awhile and I've always used:

The same on the ground as posted above and in the air, instead of putting a hard number on it, like -35 or -40 SAT, I use the FDX rule of 9, which is to take your mach number (.82) and if the TAT is below zero (which 99% of time it will be in G), you add that to your mach number (-10 TAT) = 92. Only use the engine heats when this results is less than 90 (and in visible moisture).

ex. mach .80 and -8 TAT outside = 88 = heats on
ex. mach .80 and -10 TAT outside = 90 = heats off

Works well for me. I used to use -35 SAT, but there seems to be a never ending argument as SAT, TAT, FAT, or whatever and what temp.

BTW, nice article in ProPilot.

 

[caseyd]

agree with everyting but the off should be 40 SAT not TAT

You are absolutely correct, my bad.

caseyd

 

[G100driver]

Does anyone know what that is? FAT??? In 34 years flying Gulfstreams I have never heard of that.

I am eager to hear others opinions.

Jeff

Why yes, Jeff, I do know what that is. That is what happens to pilots eating catering served to them on china by flight attendents.

Sorry, I could not resist!

As for the TAT/SAT debate, in the newer Dassault's they use TAT. I cannot remember what Dassault said to use in the Falcon 10.

 

[PAA744]

+5C Tat to +10C Tat

5 tat to 10 tat dat was da option.

if below 10 tat - engine ice should be on prior to 5 tat (temp decreasing)
if above 5 tat - engine ice should be off prior to 10 tat (temp increasing)

Made for a very simple operation - but it worked !!!!

ps convert the C nembers to F numbers

 

[gutshotdraw]

C'mon Jeffrey,

The G-V is au-to-ma-tic. In the dark ages G-IV, visible moisture and +8 to
-40 SAT as indicated on the ND. If you really want to be anal, the temperature vs. Mach number chart is in the QRH.

 

[ultrarunner]

I am curious what other operators use as far as anti-icing criteria is concerned. Do you use SAT or TAT? The Gulfstream manual also refers to FAT. Does anyone know what that is? FAT??? In 34 years flying Gulfstreams I have never heard of that.

I am eager to hear others opinions.

Jeff

We do what the AFM tells us. Simple as that....

On ground and in visible moisture 10C SAT or less. Engines only.

In flight, in visible moisture ( or no assurances against entering it) ON 10C SAT or less. Engines AND Wing bleeds.

Pretty simple stuff, and every airplane I have flow the Anti-ice OR de-ice system use has been clearly defined.

However, in the corp world, you'll usually find someone that thinks there is a better way. They're usually wrong.....

 

[SiuDude]

If memory serves me correctly, FAT = Free Air Temperature........I think it's a fancy way of saying OAT (outside air temp). I'm pretty sure that in my past I used to fly an aircraft with a FAT gauge, but for the life of me....I have no clue which one it was.

The King Air 200 I flew had a FAT gauge.

 

[falconpilot]

Why yes, Jeff, I do know what that is. That is what happens to pilots eating catering served to them on china by flight attendents.

Sorry, I could not resist!

As for the TAT/SAT debate, in the newer Dassault's they use TAT. I cannot remember what Dassault said to use in the Falcon 10.

FALCON 10 HAS A RAM GAUGE. WE ALWAYS USED IT.

 

[Blackjet]

However, in the corp world, you'll usually find someone that thinks there is a better way. They're usually wrong.....

That is so true, and not just about temperatures.

As for the temp issue:

In the air:
TAT/RAT (Essentially Skin Temperature of unprotected surfaces):
Above +10, nothing. No manufactuer or the FAA has seen ice form on any surface above this temp.

Below +10 TAT/RAT, reference SAT.
If above -40c (but less than +10c TAT), then Anti-Ice on in Vis moisture.

It's just that simple, though I do like the FEDEX explination posted above.

The TAT/RAT is also a great tool for deice and Anti-Ice. Get some ice that you can't shed due to a malfunction or whatever, push that power up. As the airplane accelerates, watch that guage climb. If you're low enough and can get fast enough to get above +10, it'll keep ice off of ALL surfaces and shed any that you have already picked up.


I have flown with people who just turn them all on no matter what the temp when they get into clouds. That drives me nuts. It's +20c and clickity, click, click. Now they seriously think the airplane (engines) takes a performance hit when it's in the clouds; Wondering aloud why they have to lower the nose to keep the speed they had when they were out of the clouds. No joke. I just smile and keep my mouth shut. Uggggrrrrrrrrrrr!!

 

[HMR]

We do what the AFM tells us. Simple as that...

Good answer.