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Guest lavis1930

PMDG 747-400 IRS alignment

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Guest lavis1930

I have a number of questions about this wonderful sim and I intend to ask tham one at a time.I like starting with a dark cockpit and getting it all going. However when I start with the standard dark cockpit at KPSA I am unable to align the IRS. I have tried settings 0 Sec., 15 sec., and the standard 10 minutes and the alignment never succeeds in getting the IRS units to work. The aligning symbols appear but no luck.The instructions say switch directly to NAV. What do the Align and ATTR(Have I go that right?) do?I get the aircraft going alright, engines running take off etc. all done on the FMS and I have sucessfully run several flights.Any ideas about what I am doing wrong?David CL Francis

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Guest fsdave

To align the IRS, firstly, you switch all the IRS's to ALIGN. You will then hear a beep (depending on how long you have set the alignment time for). You then open the FMC and there should be an FMC message saying "ENTER IRS POSITION" - or something like that. Then select the POS lsk in the INIT/REF index. You then copy the GPS POS to the IRS POS lsk. Sometimes you have to do this twice because another fmc message appears - don't know why. Finally, you switch all the IRS switches to NAV.Hope this helps

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Not correct.Enter your position in the FMC POS page. You may have to enter it twice, if the aircraft's prior position is different than the one you just entered (i.e. the FMC will beep, and require confirmation of the position).Then, switch your IRS knobs to NAV, and wait for the alignment.FYI - The ALIGN position is for a "quick" align, assuming that the IRS has previously been aligned. Hence, you will never use this if you start from a "cold & dark" scenario.- Bill


- William Ruppel, CYKF, VATSIM 816871

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Correct, Bill.Selection of ALIGN is also required in high latitudes where the IRU's need longer to align (instead of the fixed 10 minutes in NAV).Note that in the real world, you shouldn't have to enter your position twice. This is a FS thing.CHeers.Q>

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Guest lavis1930

Thank you guys for the replies. I sucessfully did it this morning. It is slightly bizarre but not too much trouble as long as you know about it. (Or at my age forget about it - never mind, the complexities help keep my mind more or less ticking over.)David

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