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The A32NX & A380X Project are community driven open source projects to create free Airbus aircraft in Microsoft Flight Simulator that are as close to reality as possible.
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IRS align should cancel if the plane is moved #291

Open Zyonix007 opened 4 years ago

JackZ974 commented 4 years ago

IRS you mean?

Zyonix007 commented 4 years ago

Yes

On Tue, Sep 1, 2020, 3:20 AM JackZ974 notifications@github.com wrote:

IRS you mean?

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Benjozork commented 4 years ago

Do you have a reference for that behaviour ? As in aircraft manual, personal experience. Useful for backreferencing.

Zyonix007 commented 4 years ago

It does on the toliss

On Tue, Sep 1, 2020, 11:14 AM Benjamin Dupont notifications@github.com wrote:

Do you have a reference for that behaviour ? As in aircraft manual, personal experience. Useful for backreferencing.

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ukflyer commented 4 years ago

Honeywell training (Sorry dont have FCOM) says it will restart alignment if it detects excessive movement. Hope this helps :)

from point 00:50 https://www.youtube.com/watch?v=t2yzsc3y1R8

JackZ974 commented 4 years ago

Yes … On Tue, Sep 1, 2020, 3:20 AM JackZ974 @.***> wrote: IRS you mean? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#291 (comment)>, or unsubscribe https://github.com/notifications/unsubscribe-auth/AOKEXPQZBATLIUCUVOWD6PTSDSOCNANCNFSM4QRC7MKQ .

So please correct the title of the issue to avoid misunderstanding.

JackZ974 commented 4 years ago

It does on the toliss … On Tue, Sep 1, 2020, 11:14 AM Benjamin Dupont @.***> wrote: Do you have a reference for that behaviour ? As in aircraft manual, personal experience. Useful for backreferencing. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#291 (comment)>, or unsubscribe https://github.com/notifications/unsubscribe-auth/AOKEXPVANXCTMD4C4DPYCPDSDUFVNANCNFSM4QRC7MKQ .

No kidding. Your reference is yet another sim? Anyways. the Inertial Reference System principle relies on a precise departure position determination, and by determining the exact lon/lat/of the airplane, along with a precise determination of the gravity vector (sorry for the FlatEarthers, but since Earth is a sphere, the gravity vector always points toward the center of Earth).

From this position, it will derive the new A/C position over time by measuring accelerations and rotations along each X/Y/Z axis that occurred since the initial plane setup, then deriving from acceleration the speed and from there the distance it moved in whichever axis since last time it measured. By cumulating those distances, it should be able to know it's position without any external input, even though on the Bus' the IRS is backed up by GPS and DME/DME informations if available to produce a more precise MIX IRS position.

All of the above resides on the precise determination of the initial position during the init process, where the only thing that should be moving is the planet earth itself, sensed overtime by a change of the gravity vector orinetation.

To sum it up, if the A/C moves during IRS initialisation (determination of precise initial position of the A/C on Earth), the whole process has to be restarted.

adenflorian commented 4 years ago

Please provide more info on what specifically should happen. should any fault lights come on? ECAM messages? Does it have to start from the very beginning? What happens while the plane is moving versus when it finally stops?

Zyonix007 commented 4 years ago

If the plane moves then the fault lights come on and you must realign irs

On Tue, Sep 8, 2020, 1:37 AM David Valachovic notifications@github.com wrote:

Please provide more info on what specifically should happen. should any fault lights come on? ECAM messages? Does it have to start from the very beginning? What happens while the plane is moving versus when it finally stops?

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tradari commented 4 years ago

A full align can take up to 10 minutes but you certainly do not have to switch them off for 10 mins. Off and on within 5 secs will give you quick align so longer than 5 will give a ON BAT plus full align

The reason for the quick align is there is drift in the system and after every 2 flights it should have a quick align performed

info taken from Pprune.org a real pilot forum

tradari commented 4 years ago

There a great video on the airbus IRS panel on you tube made by honeywell you can find it here https://www.youtube.com/watch?v=t2yzsc3y1R8

lrargerich commented 4 years ago

Shall we just ignore this? I mean it is realistic but MSFS has a devilish pushback and ATC behaviour and sometimes you find the plane starts to move without you wanting it to move at all. Not everybody disables default ATC or AI handling ATC and it could be a source of headaches. Just saying for the sake of a good experience. This also goes with the idea of IRS aligning quickly via some command.

Zyonix007 commented 4 years ago

no please dont it adds a ton of system depth

On Tue, Sep 8, 2020 at 4:49 PM Luis Argerich notifications@github.com wrote:

Shall we just ignore this? I mean it is realistic but MSFS has a devilish pushback and ATC behaviour and sometimes you find the plane starts to move without you wanting it to move at all. Not everybody disables default ATC or AI handling ATC and it could be a source of headaches. Just saying for the sake of a good experience. This also goes with the idea of IRS aligning quickly via some command.

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Benjozork commented 3 years ago

The problem with this is that no matter what kind of digging I do in manuals, training videos or ECAM systems logic data, I cannot manage to find anything related to the plane moving during IRS align. Furthermore, it's something we cannot ask pilots to do test for obvious reasons.

We are going to have to dig deeper into this, but I'm afraid it might just let the process go on with massive errors.

Zyonix007 commented 3 years ago

It does on the fslabs. Additionally it would be logical for the irs to cancel cause it can't align if you move spots. Even the pmdg 737 has this feature.

On Mon, Oct 19, 2020, 12:31 AM Benjamin Dupont notifications@github.com wrote:

The problem with this is that no matter what kind of digging I do in manuals, training videos or ECAM systems logic data, I cannot manage to find anything related to the plane moving during IRS align. Furthermore, it's something we cannot ask pilots to do test for obvious reasons.

We are going to have to dig deeper into this, but I'm afraid it might just let the process go on with massive errors.

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JLD95 commented 3 years ago

Hi, I am working on Inertial Navigation Systems. Alignment is very sensitive to movements of aircraft. An IRS contains an internal algorithm which tests the outputs of its inertial sensors gyrometers and accelerometers in order to detect movements. Very slow motions are very difficult to be detected by these sensors: for example when parking brake are released and parking has a very small declivity. So it's pilote responsibility to assure an static aircraft but IRS autonomously detects movements and switches to IR Fault mode. The 3 irs can be misaligned due to a very slow movement and this constitutes a common mode for the operational safety of the navigation system Available for more technical informations if necessary.

adenflorian commented 3 years ago

If we can't find IRL references on how this should work, then I think it's fine to base our implementation on how other payware aircraft handle it.

The3dVehicleguy commented 11 months ago

I want to add some insight to this issue. I came across this issue just now and want to bring up my knowledge with working on multiple aircraft and developing flight simulators for civilian and military use. There is the possibility that if the IRS is in alignment and the Parking Brake is released then an ECAM alert will be triggered and the IRS alignment will be paused or canceled all together requiring you to apply the parking brake again and recycle the ADIRS alignment knobs to the OFF then NAV position. A lot of aircraft have this interaction when in alignment and I wouldn't be surprised if the Airbus has the same setup. I would ask for someone to look through the manuals to see if this is the case.