Navigation/IRS Mistake

[BobbyBond2 0]

Greetings All -

 

Last evening I was planning a flight from KBWI to KBUF as normal and ran across something I couldn't fix.  For some reason, the Captain NAV displays showed correct navigation information on the CDUs.  However, the F/O's displays showed the "generic" displays with no heading or navigational information (Speed, Heading, VS, etc).

 

I honestly don't know what I did and what I could have done to correct the issue. 

 

I loaded the 737NGX Cold & Dark

Turned on the batteries

Connected GPU

Turned on External Power

Set IRSs to Align/NAV

Entered IRS position in MCDU

 

Captains Displays updated but FO's did not.

 

Any thoughts?  I was really confused because I couldn't correct it.  So on a whim, I decided to fly but could not engage autopilot (my guess is due to the FOs nav displays not being updated).  

 

I handflew the whole way to Buffalo so it was a win/win in the end

 

Thanks in advance!  See everyone on the forums during 777 release!

 

 

[et31 39]

 

 

Greetings All -



Last evening I was planning a flight from KBWI to KBUF as normal and ran across something I couldn't fix. For some reason, the Captain NAV displays showed correct navigation information on the CDUs. However, the F/O's displays showed the "generic" displays with no heading or navigational information (Speed, Heading, VS, etc).



I honestly don't know what I did and what I could have done to correct the issue.



I loaded the 737NGX Cold & Dark

Turned on the batteries

Connected GPU

Turned on External Power

Set IRSs to Align/NAV

Entered IRS position in MCDU



Captains Displays updated but FO's did not.



Any thoughts? I was really confused because I couldn't correct it. So on a whim, I decided to fly but could not engage autopilot (my guess is due to the FOs nav displays not being updated).



I handflew the whole way to Buffalo so it was a win/win in the end



Thanks in advance! See everyone on the forums during 777 release!

 

Hi Rob,

 

Sounds strange!

 

I would move the IRSs to off then back to Nav and try to do an align again.

 

Failing that use the source selectors on the overhead panel to make the captains the only source.

 

Do you have failures turned on?

 

Kind regards,

 

Greg

[SMITI07 53]

Does sound odd. Could have been a Service Based Failure.

[scandinavian13 5,192]

 

 

Any thoughts?  I was really confused because I couldn't correct it.  So on a whim, I decided to fly but could not engage autopilot (my guess is due to the FOs nav displays not being updated).  

 

When you align the IRSs, there may be a delay between the two of them.  Additionally, are you sure you selected NAV (right click twice) for both?

 

Sounds like it could've been a procedural error.

[BobbyBond2 0]

My guess it was something procedural or I clicked something incorrectly.   I tried moving IRSs to off then back on.   I believe my service based failures are turned off.  

 

I'll see if I can reproduce tonight

 

Thanks all!

[Tyrion 2]

I had the same thing happening to me some weeks back, but it was the captain's IRS not aligning in my case.

When I turned both IRS's to NAV, the FO's aligned normally after the expected amount of time, but the Captain's side didn't. I even let it run for 30 minutes once, no progress.

 

Using the CDU failures menu to 'clear all' failures fixed it for the running flight, but the problem returned the next flight. (although no failures were indicated at any time in the menu).

 

The next flight I 'cleared all' failures, but also ran a full maintenance on my airframe, and the problem went away and hasn't returned since.

 

Note that I did have service based failures enabled.

[davierosoft 13]

If the position is entered in the CDU before one IRS is in ALIGN (so it is with ON DC light on and ALIGN light OFF) the position will only be acquired by the IRS in aligning mode.

This is a classic thing when you do the things very fast. The ENTER IRS POSITION will become empty again and will ask to insert the position again for the second IRS.

However, if the problem continues see the error code on the ISDU