G3Xt Advanced Gauge Configuration

[Avanza]

I´m testing a "new" feature using the G3Xt Advanced Gauge Configuration, a Warning for ICE, using the fuel flow and airspeed.
Flying in IMC or at night makes it more difficult to detect ICE and it could be handy to have an alarm.
The idea is based on the fact that ICE will slow the aircraft down if power setting is fixed.
My normal TAS is >160 kt and therefore I have choosen to set the airspeed threshold to 145 kt. This setting may change.
Fuel flow in normal level flight in my plane will in most cases be between 7-11 gph. Climb and decent will be on the outside of this range.
As there is no standard label in the G3X system, I have choosen to present the ICE alarm on the rpm meter as RED range.
My engine is a standard 180 hp IO-360. Fuel flow in this case is a representation of engine power where 7 USG is about 50% and 11 USG is 75%.
An alarm will be triggerd if Fluel flow is between 7-11 gph and airspeed <145 kt and altitude above 2000 ft GND and after a time delay of 60 s.
Fuel flow below 7 gph or above 11 gph or airspeed above 145 kt or altitude below 2000 ft GND will not trigger the ICE alarm.
Flying in icing condition is dangerous and have taken down aircrafts. Settings used in this example may not be safe.
Testing is ongoing with only a few hours flown.

Configuration:

On the fuel flow Gauge Display, Edit Gauge Marking.
- set: Invisible range*
- set: Minimum: 7 gph
- set: Maximum: 11 gph
- set: Mode: Set Logic Signal
- set: Signal: 1 (or other that is not used)
On the Logic Signal Configuration page and signal 1 (or other that is not used).
- set: Time delay 60 s
- set: Airspeed threshold: True Airspeed / Below/ 145 kt
- set: Altitude threshold: Height AGL/ Above/ 2000 ft
On the rpm Gauge Display, Edit Gauge Marking.
- set: Red Range + Alert
- set: Minimum: 1500 rpm
- set: Maximum 2100 rpm
- set: Mode: Require Logic Signal Set
- set: Signal: 1 (or other that is not used)

Good Luck

 

[mburch]

I haven't tried this to be sure, but if you have an unused discrete input I think you might be able to use it to get a custom CAS message for your chosen conditions:

1. Set up the unused discrete input so it's always active (either configure it as Active Low and wire it to ground, or configure it as Active High and let it float)

2. Give the discrete input a name and alert color of your choice

3. Configure the discrete input for "Require Logic Signal Set" and connect it to your chosen logic signal. This will prevent its alert from appearing unless the logic signal is set.

4. Optionally, delete the red range on your RPM gauge, since if this works it's no longer necessary

 

[rocketman1988]

My question is how you propose testing this idea? Are you going to fly into icing conditions?

It is also likely that by the time you see a noticeable reduction in speed, you will have accumulated a significant amount of ice.

People don't realize just how fast ice can build up on an airframe.

In our RV aircraft, the only winning move is not to play.

 

[Avanza]

I haven't tried this to be sure, but if you have an unused discrete input I think you might be able to use it to get a custom CAS message for your chosen conditions:

1. Set up the unused discrete input so it's always active (either configure it as Active Low and wire it to ground, or configure it as Active High and let it float)

2. Give the discrete input a name and alert color of your choice

3. Configure the discrete input for "Require Logic Signal Set" and connect it to your chosen logic signal. This will prevent its alert from appearing unless the logic signal is set.

4. Optionally, delete the red range on your RPM gauge, since if this works it's no longer necessary

Thank you Matt, verry helpfull information.

Good Luck

 

[Avanza]

My question is how you propose testing this idea? Are you going to fly into icing conditions?

It is also likely that by the time you see a noticeable reduction in speed, you will have accumulated a significant amount of ice.

People don't realize just how fast ice can build up on an airframe.

In our RV aircraft, the only winning move is not to play.

I´m retired now and I have experienced icing before. I don´t have to deliberately fly in to icing condition just to test it.
Ice can come slowly or verry fast and is always a risk depending on the type of wing and if deicing is available .
My experience is that an ice thickness of 3/8" will slow a small aircraft about 10 kt, however aircrafts does not behave equal in ice.
The best situation is of cause not to fly in icing condition, but soner or later you may accidentally encounter ice.
If you have some sort of warning it may prevent an accident. This is especially true at night when icing is not easy to see.

Good Luck

 

[Ezburton]

OAT should be considered as an input. Seems you might also need a flap retracted input since you are basing your ice detection on drag. Of course, if you do have ice, you wouldn't want to put your flaps down (for any reason) anyway.

The stall speed with just frost on the wing increases by over 20%. Should probably change the speed tape stall speed or lower the AOA if you display that.

If it is this big of a concern for your application, you might want to install a light which shines on the leading edge so you can see it.

MTCW

 

[dmattmul]

I haven't tried this to be sure, but if you have an unused discrete input I think you might be able to use it to get a custom CAS message for your chosen conditions:

I think this what you mean and definitely can set an unused discrete to assign a certain parameter. In this case I set up a CAS message to remind me to push the prop in when the airframe is set for landing configuration. You can even set an audible to it.

 

[rocketman1988]

I´m retired now and I have experienced icing before. I don´t have to deliberately fly in to icing condition just to test it.
Ice can come slowly or verry fast and is always a risk depending on the type of wing and if deicing is available .
My experience is that an ice thickness of 3/8" will slow a small aircraft about 10 kt, however aircrafts does not behave equal in ice.
The best situation is of cause not to fly in icing condition, but soner or later you may accidentally encounter ice.
If you have some sort of warning it may prevent an accident. This is especially true at night when icing is not easy to see.

Good Luck

Again, if you don’t fly into actual icing, how do you know if your idea actually works?