Eau light won't go off

[chucky35uk]

On learning how to properly start this delightful aircraft....I can get all lights off on the caution light panel except the enhanced attitude control bulb. I have turned the eac switch to on during startup.....but won't go out.

Anyone any ideas as to what's wrong?

Thanks.

:helpsmilie:

[Oznerol256]

In order for the EAC (Enhanced Attitude Control) you need to make sure your EGI has aligned itself and your NMSP is set to use the EGI. Step by step:

 

Make sure the CDU and EGI are powered (the switches are on AAP).

 

Look on the CDU or the CDU repeater page on one of the MFDs for the flashing "INS ready". It will take a few minutes until it appears.

 

Click the button next to NAV on the CDU or the MFD.

 

Press the EGI button on the NMSP.

 

Activate the EAC.

[NoCarrier]

For EAC to engage properly, you need the full four minutes of INS alignment, you need to have all SAS channels turned on, and you need to be in EGI mode.

 

Let me know if you need help with any of the above. I realize it can be one big alphabet soup when you first start out.

[Madone]

Don't forget the pitot heating system as well.

[NoCarrier]

Don't forget the pitot heating system as well.

I don't think the pitot heating system is part of the EAC, as far as I know.

[chucky35uk]

Eac light

 

Blistering response gents......

I will give your recommendations a try shortly and get back to you.

Stand by.

Thanks again.

[Madone]

It's not part of the EAC indeed. But IIRC the EAC provides the autopilot modes through the LASTE. LASTE get the data from the pitot among other things, if the pitot is frozen, the data provided is wrong and the EAC will swith back off anyway.

[chucky35uk]

Wonderful.....it was the egi switch....setting the cud to nav... Then egi... has turned light out.

One small step for man.......

Although I have loads more to learn...

Thanks again...

[NoCarrier]

It's not part of the EAC indeed. But IIRC the EAC provides the autopilot modes through the LASTE. LASTE get the data from the pitot among other things, if the pitot is frozen, the data provided is wrong and the EAC will swith back off anyway.

A blocked pitot tube will cause a CADC (Central Air Data Computer) failure, yes, which in turn will trip EGI and EAC with it. So far I agree with you. But that doesn't mean pitot heating is actually essential because EAC needs it.

[Madone]

Looking at the numerous crashes of planes IRL caused by ice on the pitot tube, that's not the kind of thing you wanna see OFF. The pitot is essential for a lot of things, not for the switch to turn on at start up but I always turn it ON on the ground cause I'm occupied at something else when I fly.

[BigfootMSR]

You can load the nav info and switch to EGI before the INS if fully aligned, But the EAC will not arm until the INS alignment says 4.0.0.8 on the CDU. Basically, as NoCarrier mentioned above, you need wait out the 4 minutes for the alignment of the INS system.

[Luzifer]

That said, EAC activation is somewhat dodgy in my experience. Often after starting everything up everything else and switching on EAC as the last action before taxiing, the EAC warning light stays on. I double and triple check that everything required is activated and can find no reason it shouldn't just work.

 

Sometimes I say "whatever", leave the EAC switch in the on position and taxi to the runway and during takeoff prechecks I see the EAC light is off. Other times it just turns off during the time I look around searching for things I might have forgot (just looking, not actually touching anything).

 

INS is aligned and in NAV mode of course.

[Oznerol256]

Did you select the EGI on the NMSP? No, just kiddin.

 

In my experience, as long as you dont forget anything, the EGI works like a charm. I never halad any problems with it (except for the times when i forget something).

 

Can you post a track with the EGI not working correctly even though you didnt forget something?

[Yurgon]

Can you post a track with the EGI not working correctly even though you didnt forget something?

 

Yup, a track would be a good idea. I haven't flown/started the A-10C in 1.2.4 yet, but in the past when I had problems with EAC I had simply forgotten one or two steps.

[NoCarrier]

That said, EAC activation is somewhat dodgy in my experience. Often after starting everything up everything else and switching on EAC as the last action before taxiing, the EAC warning light stays on. I double and triple check that everything required is activated and can find no reason it shouldn't just work.

 

Sometimes I say "whatever", leave the EAC switch in the on position and taxi to the runway and during takeoff prechecks I see the EAC light is off. Other times it just turns off during the time I look around searching for things I might have forgot (just looking, not actually touching anything).

 

INS is aligned and in NAV mode of course.

If you toggle the EAC switch through your HOTAS, the switch can actually appear "armed" due to continuous input overriding the "EAC off" trip. Maybe that's the case here. In this case, I would trust your anunciator panel more than I would the position of the switch.

 

EDIT: thinking some more about it, isn't EGI automatically selected for you when you start taxiing if you haven't already? I seem to remember something like that. It would explain the behavior Luzifer described above.

 

EDIT AGAIN: after a little searching, it looks like it's the EGI Nav mode that's automatically selected for you. I would hazard a guess that this Nav mode is also a requirement for EAC here. Your EGI can be fully aligned, after all, and still not working because it's in alignment mode.

Edited May 8, 2013 by NoCarrier