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Excess IRS Motion


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Totally blown away by this addon, this coming from someone who prefers study level stuff, and who, just solely because of this addon made me for the first time since FS98, buy and use X-Plane! I never thought i'd see the day I would use Xplane.


Anyway, I was parked on the ramp and KACK tonight, and during the preflight the IRS's wouldn't align. Every 2 minutes or so I kept getting the Excess IRS Motion message resetting the alignment time to 6.7 minutes. I figure it must be the wind as at the time according to ASXP it was 350 at 27 gusting 40. Having the parking brake and chocks in apparently didn't help


Is there a way around this issue?

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I know that's cheating but maybe "Realignment IRUs Immediately" works? 

It sounds like that might happen in the real world as well. My wild guess is that one way (in the real world) would be to tow/taxi the plane to an area that's better protected from winds (e.g. into a hangar, maybe a runup area with blast shields would also be sufficient?). I've never tried if X-Plane simulates objects shielding from wind though (and it might just not do it, it's usually not important to simulate that), so maybe the "cheat" is the only option.

As an afterthought... If X-Plane does not simulate wind shielding inside hangars etc. we can still control the winds within the simulation. So to simulate shielding from strong winds e.g. inside a hangar it would be possible to temporarily override the winds to be calm in ASXP and restore live weather after the alignment has finished. :)

Edited by EnQ
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The real IRUs should not be affected by wind unless the wind is so strong that the aircraft is rocking side-to-side. The IRUs are designed to ignore minor displacements in the vertical plane during alignment, such as might occur if a crew member boards or exits the aircraft, (though refueling is not advised when aligning, as the gear struts can suddenly compress as fuel weight is added). However, any significant motion in the roll axis caused by wing rocking can disrupt the alignment. This is most likely to occur if the wind is coming from the side, and can be minimized if the nose is pointed into the wind (if the direction is known).

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Toto showed this off in a few of his development streams. It is very likely that it was due to the wind gusts.

In reality, the solution to this is "tow the airplane somewhere where it's not getting buffeted by the wind (like behind a building or fence), or at least point it into the wind so it's not yawing".

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