IRS Errors

[Guest The_Glideslope]

HelloWhen flying the 737 NG (600/700 Boxed version) I fly the first flight with no problem in the FMC POS INIT page works fine. Upon arrival I shutdown the aircraft and when I turn it on again and go to the FMC it still had the initial airport references (LAST POS Coordinates) in the POS INIT page.Even if I reload the a/c it still maintains the first airport position which then creates several errors if I continue with the next flight.My question is this: The 747 doesn't do this. Upon system shutdown it records the last IRS position for reference. How can I reset this information in the 737 FMC? Must I exit FS9? Like I said I don't need to do that in the 747 or even the PSS777 or LVLD767.

[Guest The_Glideslope]

UPDATE- I read the manual and it states that there's no IRS alignment??? how come I get all sorts of errors from this LAST POS innacuracy?

[Tabs 2,790]

Jon,The NG doesn't have an IRS. I believe what you need to do is delete your origin and dest fields on the FMC RTE page 1, then enter new ones for the next leg of the flight... This should reset the FMC.

[Guest The_Glideslope]

I seeSo I understand that in order to make the FMC work after another flight is to input new data? This doesn't make any sense, since what I am saying is that the LAST POS records the FIRST parking situation, when it should record the LAST. This sounds like a bug to me.Another point is that in the FMC MANUAL in the POS INIT description page it states procedures to align the IRS claiming that in "the future" a patch is planned to make this feature available. This is an important feature that is part of the airplane PREPARATION in the Normal Procedures Checklist.

[Guest Hawkeyeted]

PMDG didn't model an IRS in the 737NG like they did with the Queen. That said, when you enter your current position in the INIT REF page, you are "virtually" aligning the IRS.All you have to do is tell the FMC where you are prior to loading your new route of flight.

[Tabs 2,790]

And yes, you do have to enter a new origin and dest on RTE page 1 in the real FMC to reset the data - you can't very well just take off again with the old origin and destination in there.I'm not sure exactly what you mean on the LAST POS thing...

[Guest Hawkeyeted]

>I'm not sure exactly what you mean on the LAST POS thing...A real IRS system "remembers" its last know position at shutdown. Perhaps he was asking why the NG doesn't do that?

[Guest tomahawk_pa38]

Jon,I always have problems with a second flight - don't know why, but after I land, I shut down, reload the default Cessna, shut it down ans reselect the PMDG aircraft.If I don't do this I always get some peculiarity with the flight.Start from scratch every flight is my advice.