B777 Funny FMC behavior. Any explanation?
 

http://postimg.org/image/irkjfisv5/

http://postimg.org/image/irkjfisv5/

After crossing the Atlantic eastbound, put EGAA in fix pg, was putting Rwy in use bearing (as a usual habit) saw something weird. Tried to change to random airports, random bearings, result was whatever the input bearing was, got changed to display something else.

After a while it got sorted out on its own, and next flights it never got repeated.

Which AIMS Blockpoint version?

AIMS BP VERSION 16

Could be a fault with the heading reference switch which displays true and magnetic heading information. You may be seeing the magnetic variation between what you select and what is displayed.

I’ve had this before and I think it might be due to software latching the incorrect datum (true/mag) as the above post. Recycling the HDG REF switch seemed to clear it on both occasions...

One of the pre-flight software test functions is to mimic this scenario during the DME selection eval. Did the system try a reboot/re-acquisition of data??

I tried recycling, it did go back to normal later, however as long as the anomaly existed, the 'latching' as u mentioned didn't change the heading scale as it should during the usual selection of the switch. The 'latching' (assuming that was the case) only modified my entry of bearing as 'true input' on Fix Page, and applied variation to it.

Right FMC Did the same.

Will look up the FOT bulletin but due to operator difference might not have. Will try googling.

agg_karan,

Is the MCDU on that bird a Smiths/GE Aviation version, or of Honeywell vintage??