[REPORTED] INLET ICE Warning message

[Rainmaker]

I’ve only ever seen anti-ice systems self-contained on the engine (nose cone/veins), but not to say the F/A-18 doesn’t pipe it back into airframe side ducting.

[Knives]

I'm mistaken indeed. The Anti Ice Probe is the lower one at 4 o'clock, the upper one at 2 is the Inlet temp sensor.

 

 

No visual of the Inlet Ice sensor.

 

Here is the prob connected to Eng Anti Valve.

 

 

[Rainmaker]

No, I think you had it right the first time. The one on the inlet should be the T2 (or another temp/pressure probe?) at 4. The Inlet Ice probe should be the upper one.

 

Let me rephrase the self-contained comment. I was referencing the bleed air portion and how the hot air is piped. Common for the Ice probe to be located on the aircraft itself and not the motor.

Edited July 10, 2018 by Rainmaker

[howie87]

OK, I've done my own thorough testing now.

 

The icing advisory appears below ~30k ft whenever the outside air temperature is below freezing.

 

Turning engine anti-ice on and increasing Mach has no effect. It seems to go away after a certain amount of time and then return again regardless of whether corrective action is taken.

 

I think we can safely say this is a bug now.

Edited July 11, 2018 by howie87

[Rainmaker]

 

Turning engine anti-ice on and increasing Mach has no effect.

 

Neither should necessarily. They are not reactive measures to make the light go away, they are there to protect the engine from Ice FOD.

[howie87]

Neither should necessarily. They are not reactive measures to make the light go away, they are there to protect the engine from Ice FOD.

 

Read the NATOPS.

 

If visible icing exists on the LEF's there are separate procedures to protect the engine from ice FOD.

 

If no visible icing exists there are procedures to prevent ice buildup (Engine anti-ice switch ON, increase Mach, INCREASE INLET TEMPERATURE ON THE DDI, climb/decend above/below icing conditions).

 

When clear of icing conditions AND CAUTION REMOVED - Engine anti-ice switch OFF.

Edited July 11, 2018 by howie87

[Vitormouraa]

I still think it's off in some way. There's been quite some discussion on it, I posted this over there:

 

 

That was roughly at 14-15 kft ASL. 55°. I guess it's C regardless of the usual imperial units used in the US where F is commonly used for temps. Even if it was F, it would still be well above the freezing point of 32°F. So the warning deifantely doesn't even come close to make sense. Also, in the miz I flew there (my basic Gulf testbed), I set the temp to 28°C, so following the rule of thumb to subtract 2° every 1 kft, basically I'd be just around 0°C which would support your thesis.

 

On the other hoof, just some 7 minutes ago I had what's in the attachments. 10° inlet temp, no warning at all, 24 kft.

 

Usually I get the feeling the warning occurs at higher speeds, especially in dives or after diving. Didn't exactly test it out though.

 

Yes... because the inlet air temperature (T2) is a function of Mach number. The Hornet is a supersonic aircraft, the inlet system must decrease the airspeed in order for the engine to work properly. When the inlet system decreases the speed of the air, the static pressure increases, and this is followed by an increase in temperature.

 

So yes faster you go, higher the pressure and temperature will be. Because the inlet is compressing the air as well.

[Rainmaker]

Read the NATOPS.

 

If visible icing exists on the LEF's there are separate procedures to protect the engine from ice FOD.

 

If no visible icing exists there are procedures to prevent ice buildup (Engine anti-ice switch ON, increase Mach, INCREASE INLET TEMPERATURE ON THE DDI, climb/decend above/below icing conditions).

 

When clear of icing conditions AND CAUTION REMOVED - Engine anti-ice switch OFF.

 

I’ve read the NATOPS, again, it’s not a process to clear the caution light. “Clearing” the caution means getting yourself out of the evironment that is creating the caution, that doesn’t mean turning on anti ice will remove the caution. Both engine heat and increasing skin temp have to do with ice prevention and injection into the engine, not necessarily making the caution go away. If you are in an envronment that can create an icing condition, an icing condition can still exist. You are trying to infer the flight manual says something that it does not.

 

There’s good reason we don’t maintain aircraft or troubleshoot problems with a flight manual, we have completely seperate operational manuals and data for that.

[Rainmaker]

 

The inlet ice system is a pretty common system amongst fighters and operate using the same basic components and system design

[Vitormouraa]

Rainmaker, I don't think Howie is talking about that. The topic of this thread is about the Inlet icing linked to outside air temperature rather than the inlet temperature.

 

If you fly really fast, you can BOIL water in the inlet, therefore no icing conditions should exist, that graph used to explain the icing zones is tied to the inlet temperature. In DCS it seems to be tied to the Outside air temperature (OAT). And that's wrong.

 

What Howie is saying is, if you find yourself in icing conditions, where the Ice detector light comes on, you can simply increase your T2 by increasing your Mach number. But regardless if you do that or not, the icing conditions are liked to the OAT, and not the conditions in the inlet duct, which is COMPLETELY different from the atmosphere.

[howie87]

Ok, now we're getting somewhere. I'm not saying that activating the anti-ice system on removes the caution or even has any effect on the icing probe. I'm saying that when the icing condition no longer exist (i.e flying outside of the Mach/inlet temp parameters that encompass the 'icing danger zone') the warning should clear as the ice on the sensor melts. This is not currently happening. Also, the inlet ice caution is displaying when flying well outside of 'icing danger zone' parameters.

[Rainmaker]

Ok, now we're getting somewhere. I'm not saying that activating the anti-ice system on removes the caution or even has any effect on the icing probe. I'm saying that when the icing condition no longer exist (i.e flying outside of the Mach/inlet temp parameters that encompass the 'icing danger zone') the warning should clear as the ice on the sensor melts. This is not currently happening. Also, the inlet ice caution is displaying when flying well outside of 'icing danger zone' parameters.

 

 

Gotcha. I think we’re on the same page now.

 

TBH, I would agree based on what I have seen. Temperature wise they have they have coding, but it’s probably under-developed on meeting the moisture requirement and probably needs more robust coding. I haven’t flown in a while, so not sure how common the light is across the spectrum of people flying. I don’t see a lot of people posting about it, that doesn’t mean that everyone is/isn’t seeingg it though.

[howie87]

The inlet ice warning comes on literally every time you fly in below zero OAT. It's that prevalent...

 

I know you're saying that inlet icing is not specifically 'tied' to inlet temp but I still think you could model icing conditions semi accurately without taking humidity into account. Sure, we might get an icing warning while there is no visible weather but at least it would be in the 'danger zone' Mach/inlet temp parameters stated in the NATOPS.

 

There are also weather settings in the mission editor that it could be tied to (clouds, fog etc).

[howie87]

Can someone from ED please confirm they're looking into this at least?

 

I've added the chart one last time so everyone can see the icing conditions that should trigger the inlet ice warning. It's all rather self explanatory.

 

INLET TEMP is available on the DDI engine display and Mach is on the HUD. It's easy to see that it's currently triggering outside of these parameters.

Edited July 11, 2018 by howie87

[Vitormouraa]

Just checked, I have an INLET ICE warning regardless if my T2 is in the icing conditions or not. For instance, the T2 below is 78°C, which should melt any ice on the Ice detector. The probe seems to be tied to the OAT.

 

Note: I was supersonic I believe.

 

[Eagle7907]

There seems to be a lot of confusion here, perhaps people are assuming T2 and Ice detector are the same thing?

 

 

 

So they aren't really the same thing.

 

 

 

The T2 probe measures the temperature before the compressor face, this sensor is not compensated/adjusted for ram rise. It will measure whatever the temperature is at that location. Generally speaking, this temperature will increase or decrease with horizontal speed. The T2 is really important for any engine and is used for so many things. T5 is a function of T2 for example.

 

 

 

But anyway, T2 will measure the temperature of the air, and it takes into account the friction and aerodynamic effects of the inlet as described above.

 

 

 

However, the anti-ice probe does not. It is compensated/adjusted for ram rise, which is the difference between SAT and TAT. This probe is not affected by the compression that takes places in the inlet system, nor the friction between the air and walls of the inlet. It simply brings the air to rest in relation to the aircraft and converts kinetic energy into internal energy. That's why you can't use the T2 probe as a direct reference, because they both measure different things, different methods of measurements.

 

 

 

As mvsgas said, the Ice detector itself isn't heated. So regardless if the anti-ice switch is on or off, if the conditions are met, there will be ice on the ice detector. If the ice buildup is excessive, a warning will appear in the cockpit. Weather the anti-ice switch is on or off. And it should go away automatically if the ice is melted (by increasing the temperature for example - increasing Mach number).

 

 

 

The problem, however, has to do with the warning light coming on in the cockpit even if you are flying at Mach 1.5, regardless of the OAT, the temperature in the inlet will be hot enough to boil water, and the ice detector shouldn't come on, because there are NO icing conditions.

 

 

 

Not disagreeing with your facts, but to me this is leaning more towards the simulation of ice accretion is excessive. I know it’s not the same aircraft but 11+ years I’ve never encountered ice accretion in clear air at any speed below .78M. I believe someone has tested and found that at 0 degree the sim starts the ice accretion regardless of visible moisture present.

 

 

Sent from my iPhone using Tapatalk Pro

[Flamin_Squirrel]

There seems to be a lot of confusion here, perhaps people are assuming T2 and Ice detector are the same thing?

 

So they aren't really the same thing.

 

The T2 probe measures the temperature before the compressor face, this sensor is not compensated/adjusted for ram rise. It will measure whatever the temperature is at that location. Generally speaking, this temperature will increase or decrease with horizontal speed. The T2 is really important for any engine and is used for so many things. T5 is a function of T2 for example.

 

But anyway, T2 will measure the temperature of the air, and it takes into account the friction and aerodynamic effects of the inlet as described above.

 

However, the anti-ice probe does not. It is compensated/adjusted for ram rise, which is the difference between SAT and TAT. This probe is not affected by the compression that takes places in the inlet system, nor the friction between the air and walls of the inlet. It simply brings the air to rest in relation to the aircraft and converts kinetic energy into internal energy. That's why you can't use the T2 probe as a direct reference, because they both measure different things, different methods of measurements.

 

As mvsgas said, the Ice detector itself isn't heated. So regardless if the anti-ice switch is on or off, if the conditions are met, there will be ice on the ice detector. If the ice buildup is excessive, a warning will appear in the cockpit. Weather the anti-ice switch is on or off. And it should go away automatically if the ice is melted (by increasing the temperature for example - increasing Mach number).

 

The problem, however, has to do with the warning light coming on in the cockpit even if you are flying at Mach 1.5, regardless of the OAT, the temperature in the inlet will be hot enough to boil water, and the ice detector shouldn't come on, because there are NO icing conditions.

 

So you're saying there are 3 probes? Ice detector, anti-ice temperature sensor, and inlet temperature sensor? Not sure I've seen anything to indicate there was 3.

[Vitormouraa]

No, what I'm saying (I should've made it more clear) that the probe is adjusted for ram rise, the difference between total air temperature and static air temperature. The T2 isn't, therefore the T2 probe will "see" an increase in temperature due to inlet compression etc.

 

SAT is the outside air temperature, TAT is the temperature adjusted for compressibility and friction. And the difference between these two is called ram rise.

[mvsgas]

So you're saying there are 3 probes? Ice detector, anti-ice temperature sensor, and inlet temperature sensor? Not sure I've seen anything to indicate there was 3.

 

Not that it matter for DCS, but there are several temp sensor within the engine to read temps at different stages

[ATTACH]189726[/ATTACH]

this is a direct pdf link

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920020182.pdf

 

And it turn out inlet temp on F404 is call t1 not t2 like I thought.

 

You can see many more parameters here, just pause the video

gyaKh7BY-6c?start=53

Edited July 11, 2018 by mvsgas

[Vitormouraa]

Not that it matter for DCS, but there are several temp sensor within the engine to read temps at different stages

[ATTACH]189726[/ATTACH]

this is a direct pdf link

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920020182.pdf

 

And it turn out inlet temp on F404 is call t1 not t2 like I thought.

 

You can see many more parameters here, just pause the video

gyaKh7BY-6c?start=53

 

Yeah that's correct. I used T2 because I thought they were referring to the NATOPS?

 

For instance, EGT of the Hornet measures the temperature between turbines, which is T5. Here's a diagram for twin shaft engines. Showing all the temperature and pressure positions.

 

[Flamin_Squirrel]

I've not seen anyone subdue l confuse the two.

[macedk]

guys guys guys ...you are all wrong!!

 

It is only the cool pilots, who get that warning ;)

[mvsgas]

:D

[Knives]

The INLET ICE caution comes on and off even if corrective actions were not take.

 

Because,

The Ice Detector system is designed to detect and report ice accretion at the engine inlet using a “heat of fusion” principle. The system checks for ice accretion at very short intervals. After two consecutive ice detections, the electronic controller will report this to the cockpit operator, and concurrently, turn on the heater to de-ice the sensor. Within seconds of deicing the sensor, the process of ice detection resumes.

 

This from Manufacturer

Edited July 11, 2018 by Knives

[Vitormouraa]

Doesn't really matter. Numbers are just stations. Different engine manufacturers make different station marks.

 

Except they don't. This is very standardized. This may vary with a different type of engine. There are exceptions but most of them follow this diagram.

 

Also that's why I said twin shaft engine. Turbojets and Turbofans.

 

We are offtopic here, let's go back to the original topic. :)