I am well into the very well prepared Tutorial #1 for my recently acquired PMDG 737NGX and am ready to fly this first flight but I've encountered a  problem which I have, so far, been unable to resolve.  Both IRS' complete their normal alignment with all lights indicating correctly for each sequential stage of the alignment process.

 

• Each IRS switch is turned from OFF to NAV and each IRS light goes from ON DC to ALIGN and upon completion of the alignment cycle to both lights being blank but a glance below shows the Capts. PFD and ND showing incorrectly I.e., no airport runway or LEGS symbology while the F/O's PFD and ND show the expected runway and purple LEG lines.

 

• The fact is that the Capt's ND and PFD are not receiving IRS input and this can be corrected by placing the IRS switch on the DISPLAYS panel on the lower overhead panel to the BOTH ON R position.  Now both Captain's and F/O's PDF and ND panels are now indicating the same.

 

• But the problem is still not resolved because even though both the Capt. and F/O sides are now indicating same they are now only driven by the right IRS.  Since the first Tutorial ends in an AUTOLAND APP which requires two functional IRS's and two functional FMS's for AUTOLAND APP the tutorial cannot be correctly completed.

QUESTION: Where did I go astray and how can I correct the problem so as to have the required two functional IRS's and/or FMS systems so as to complete the tutorial?

 

My thanks in advance.

 

Quink 99 

 

 

 

QUESTION: Where did I go astray and how can I correct the problem so as to have the required two functional IRS's and/or FMS systems so as to complete the tutorial?

 

Often, the two IRSs don't finish the spin at the exact same time. My guess is that you're seeing the FO's finish first and jumping to the conclusion that there is something wrong with the Capt side. In doing so, you're running everything off of the FO's side and beginning the flight. This movement ruins the calibration of the Capt side, and you are then truly only running off of one.

 

How long are you waiting between the one side showing as "okay" before writing the other one off?

 

 

 

Quink 99 

 

Welcome to the PMDG part of the forum. Just as a heads up, you're supposed to use your real, full name here.

Kyle,

 

WILCO on the "real name" and thanks for the prompt reply!

 

I am under the impression that once each of the two IRS lights have cycled through the full sequence of ON DC >ALIGN>blank or no light that then the IRS's are ready to input to the FMS's, CDU's and the ND and PFD's.  Is that correct? Should there be a longer yet waiting time prior to showing on the NAV and PFD panels after the IRS lights go out?

 

P.S. Thanks for the "Welcome aboard".  It seems to a great forum with a lot of helpful folks!

 

Frederick Coleman

Just to be clear, you don't have an attitude displayed on the left PFD?

Hi Frederick, what panel state are you using? I think Tutorial #1 is done with NGX DEFAULT panel state and the IRS should be already aligned.

Barry Friedman is correct. You should not load any panel state or do any IRS alignment in Tutorial 1. Panel States and IRS alignment are part of Tutorial 2.

 

 

I am under the impression that once each of the two IRS lights have cycled through the full sequence of ON DC >ALIGN>blank or no light that then the IRS's are ready to input to the FMS's, CDU's and the ND and PFD's.  Is that correct? Should there be a longer yet waiting time prior to showing on the NAV and PFD panels after the IRS lights go out?

 

Yes and no. Once they're on, you can tell them where they are in the world by entering a position on the CDU. It still takes about 7 minutes to fully "spin up" (in quotes because it's lasers now, and not gyros as it was in the past) if you're using the "realistic" option (I believe "fast" is the default, which takes about 30 seconds). Regardless of what your setting is, you'll see a countdown at the top left of the nav display. Once that is done, you should see both sides getting information, though there may be a little variation between left and right sides (time-wise).

Gentlemen,

 

All of your input has been helpful enough to make me realize that I may have inadvertently stepped on my own begonia and created the IRS problem myself.  I now think I know were I went astray and plan to repeat the Tutorial #1 from square one to verify that, with your help, I've found the solution and can make the IRS problem go away.

 

As soon as I have an hour or two I'll repeat the flight and post the results here.

 

I couldn't have done it without you,

 

Fred Coleman

 

 

All of your input has been helpful enough to make me realize that I may have inadvertently stepped on my own begonia and created the IRS problem myself.

 

haha - I have not heard that line before...

 

Glad we could help!

For those of you who may have perceived that I am not the "sharpest knife in the whole drawer" your

perception was correct!

 

After a bit more reading and thinking the IRS problem has now been resolved and a ground check verified where I'd gone wrong.  About twenty five years ago before I retired I went through one of my airline's first 747-400 classes prior to flying it on the line.  There's an old saying that "you can't teach an old dog new tricks" but in this case it was reversed; you can't make a new dog forget old tricks.  Somehow my tiny little mind had retained a procedure regarding IRS alignment in the -400 which was almost the opposite in sequence from what it is in 737NGX and using that procedure instead of the PMDG/Boeing approved procedure for the 737NGX.  That I could remember the -400 procedure is a minor miracle as I often have trouble remembering my current phone number or where I left the car keys...........it's hell getting old!

 

With the problem now resolved I shall now go back to flying PMDG Tutorial #1 and nursing my ego and crushed begonia back to health.

 

Thanks, gentlemen, for your forbearance.........OVER

 

Frederick Coleman