Hi, don't know if anyone else has come across this problem, but sometimes my right IRS will not align. The DC On light stays on when the align light flashes and I get a peculiar noise as if the IRS is trying to align but has a fault. This happens quite often now.

 

As a beginner on this fantastic aircraft, I haven't had time to read the manuals in depth, so if anyone can help, I'd be grateful as it stops me from doing a C & D start.

 

Many thanks

Hey - welcome to the forum.

 

To answer the question, I'll ask a few questions:

Do you have any failures listed in the PMDG MENU options that you can bring up via the FMC?

Did you move the plane while it was being aligned?

 

Also, take a look here:

http://forum.avsim.net/topic/245586-you-must-sign-your-full-real-name-to-posts-to-use-this-forum-posts-without-names-will-be-deleted/

What power do you have on the aircraft?

Hi, don't know if anyone else has come across this problem, but sometimes my right IRS will not align. The DC On light stays on when the align light flashes and I get a peculiar noise as if the IRS is trying to align but has a fault. This happens quite often now.

 

As a beginner on this fantastic aircraft, I haven't had time to read the manuals in depth, so if anyone can help, I'd be grateful as it stops me from doing a C & D start.

 

Many thanks

 

The QRH has info about this - but I dont have time to type it all out ;-). I have a great idea - when you have enough time to fly on FSX with the NGX then take that time and do an IRS search in the QRH - you will see what is happening and the soloution.

Try turning it off, then wait a bit and try to turn on again.

Are you sure that after establishing a suitiable source of electrical power you are placing the IRS Mode Selector Switches from OFF to NAV?

 

& not doing one of those famous 'FS'isms' & placing them from OFF to ALIGN?

Is your problem only on the left IRS or on both?

The warning you hear is the ground call?

If yes on both

I can try to tell you some possible reasons:

Aircraft not fully powered (No AC sources or only one source (or main bus) and xfer bus off)

Stby power off, this will not power the left AC IR, ON DC will be present as no AC source for him.

Normal or alternate equipment cooling fan not operational or low flow (check failures and OFF light on them), put the fans on the alternate or normal position to restore flow, or, fix the failure.

It is always the RIGHT IRS which fails to align.

 

Not sure about the power as I am using FS2crew to help me get the aircraft ready for flight.

 

I will try a manual power-up and see what s going on.

 

Dave Owens

Few things:

Do you switch them to NAV in few seconds or you put left on NAV, wait some seconds, then right on NAV?

Do you put position while is ON DC or are already both aligning?

Because if one is not yet ready to receive position from the FMC (so not in align mode) it will fail due to missing position info.

When you enter position and put it into the LSK of IRS position, the FMC will send it to the listening IR, if one of them is not in align mode (like in the few seconds after you turn it on) it will not receive position.

Check the ISDU (IRS display unit) on HDG/STS position with the selector to RIGHT IRS to check for error codes.

However, first of all check failures in FMC

Check transfer bus switch position (guarded or AUTO)

 

And obviously check AC power.