investigating INS ATT?

[SharpeXB]

Landing back on the boat was fun without a functioning velocity vector or AOA bracket 

[BIGNEWY]

I will take a look today, thanks

[BIGNEWY]

Can I ask why you are setting GND align so early?

 

Manual states Once the left engine has an RPM greater than 60%, rotate the INS knob to GND (ground) or CV (carrier), depending on your parking location.

 

 

 

[dorianR666]

i know, BN. and thx for checking the track.

 

but still this behaviour surely must be wrong. if it aligns into OK, and afterwards it deletes alignment... either it should have stayed aligned or not have shown OK.

 

the simulator code must count with the virtual pilot doing things out of procedure.

 

also it seems to happen only sometimes, real trigger is unknown to me, but lays somewhere in the timing rather than turning knob early by itself. thats not the real trigger.

Edited January 24 by dorianR666

[Rennes]

Why would the simulator code need to count on pilots not doing things in the proper order?  It's a simulator, it's supposed to behave like the real aircraft. Real aircraft have startup procedures that are followed via checklist. It's there for a reason. 

[dorianR666]

20 minutes ago, Rennes said:

Why would the simulator code need to count on pilots not doing things in the proper order?  It's a simulator, it's supposed to behave like the real aircraft. Real aircraft have startup procedures that are followed via checklist. It's there for a reason. 

Exactly.

Do you think the real aircraft shows OK and then resets the alignment?

 

If simulators should NOT count with pilot doing incorrect things, why do DCS planes have batteries running out of juice (Hornet)? Why do they have engine flameouts (Viggen)? Why do they have radar overheat (MiG-19/21)?

The behaviour should be defined, not left to random nonsense appearing on displays.

 

Edited January 24 by dorianR666

[dorianR666]

With some more testing i found the following:

 

Caution INS ATT will appear, yet HSI shows AINS. Not sure if thats possible.

Whats interesting is the velocity vector on HUD is messed up, yet position is tracked and updated perfectly well on HSI - how?

Edited January 24 by dorianR666

[Santi871]

I'll report it. For some reason it doesn't happen to me other than in your track. Doesn't even happen if I do the alignment a second time.

 

Are you able to cause it if you start alignment after the left engine has actually started up?

Edited January 24 by Santi871

[Santi871]

Oh, I see a possible cause. It seems your startup flow might be so quick that the aircraft hasn't properly acquired GPS when you move the INS knob to IFA. IFA RDR starts for a brief second and nukes your current alignment, then GPS acquires and it goes straight into AINS with a shot alignment.

 

You can check in HSI/DATA/AC. GPS horizontal and vertical error are 0 feet until GPS acquires and gives you actual error values. Also once GPS is acquired you'll get a NOSEC GPS option at PB2. I'll check if there's any advisories about GPS not having acquired but IIRC there are not.

 

tldr: slow down your startup flow

[dorianR666]

great find! thanks

that sounds like a realistic cause.

 

i saw this problem once also when aligning on ground power (though i didnt save track), couldnt replicate it again. your explanation would make sense for it too.

[dorianR666]

attached is the problem appearing entirely on ground power, without touching APU or engines.

 

indeed it is as you say. the time window is extremely narrow.

ins_bug_e.trk