AGD-1 ADI becomes unreliable after excess banking

[WildBillKelsoe]

Just did a 3 hour 15 minutes flight from Beslan to Krymsk to Beslan covering most of Georgia. I noticed that ADI becomes unreliable after excess banking or pitching that it is almost impossible under flying hood to maintain level flight under said indicator. I zoomed in all the way trying to get both wings level but the outer horizon was not in line with it.

 

Bug?

 

 

Also, which is the head and which is the tail in this image of directional gyro?

 

Addition: No instructor failures panel all switches not touched since cold start.

[Beagle One]

I don't know about the L-39 but what you describe is already a feature of both the Su-25 variants already. When you dont give the INS enough time on the ground to allign (2-3 Minutes) it will show wrong angles in ADI and Attitude indicator after some hard manouvers.

[1.JaVA_Platypus]

It is a 'feature' on older design gyroscopic instruments. It is also on the (T)P-51. Gyroscopic instruments need to be corrected all the time IIRC. Modern gyroscopic instruments have some kind of auto-correcting feature build-in.

[grunf]

Heads are pointing at 159 and 39.

[WildBillKelsoe]

I gave INS enough time that I take 15 minutes to start up. I know it takes less but how do I 'align' INS? Do I push MC sync button? Isn't that supposed to be inflight each 45 minutes?

[TaygaMongun]

There isn't an INS, nor is there a sort of 'alignment'. I'm not sure if the MC sync button corrects for the ADI, but the way I do it is to ensure I am level with the horizon or that my turn coordinator is sitting at 0, use the backup sights to line up the nose to the horizon (if you're in IMC, well, too bad, I guess you could try a VS of -1.5 ms^-1?), and then hold the cage button on the ADI and release.

Edited November 4, 2015 by faycheung
Units

[WildBillKelsoe]

or even climb enough to be out of IMC. Yes I do it your way but the alignment is for magnetic correction I believe. My topic is about ADI itself in banking. It appears imprecise and sometimes the bank is so steep that it remains there on leveling out.

[TaygaMongun]

I am indeed referring to the ADI in my last post. The corrective measures that I take are quoted below.

 

...ensure I am level with the horizon or that my turn coordinator is sitting at 0, use the backup sights to line up the nose to the horizon (if you're in IMC, well, too bad, I guess you could try a VS of -1.5 ms^-1?), and then hold the cage button on the ADI and release.

 

It is the cage button on the ADI not the MC Sync button that should be used to reset the ADI. It appears that the vertical component of the ADI isn't affected, so you can use that as a reference when correcting I suppose.

[WildBillKelsoe]

fay, I am referring to the horizontal component. So if the front pilot gets a weird indication under a hood, the instructor lifts the hood so he can reset ADI (ARRETIR?) or does he continue without resetting based on his cheek feeling which is saggier?

[TaygaMongun]

I understand that you are referring to the roll component. I do it based on the turn coordinator. I reset the ADI by aligning the aircraft so the turn coordinator sits at 0, dip the nose to the indicated horizon, reset, and fine adjust the knob if needed.

[WildBillKelsoe]

Ok, should I lower speed as I do this?

 

Sent from my SM-T231 using Tapatalk

[TaygaMongun]

Just eyeball it I'd say, no need to slow down. As I mentioned before, the vertical component of the ADI seems to be accurate, so to realign, pitch the nose so that it faces the horizon, as indicated on the ADI, ensure that turn coordinator is centred, and then cage the ADI. I have no idea if this is the correct way of doing things, I need to revisit the manual.

[WildBillKelsoe]

OK thanks.