I'm currently cruising on a flight from CYYZ-EDDM with 773ER. A little bit before entering the NAT system I went to the LEGS page and did what Kyle did in his tutorial, I entered .830/330 next to the first NAT waypoint to maintain a fixed speed and altitude, and then I entered ECON/ at the exit to resume ECON cruise and speed. However, for the waypoints in between the speed did not change to .830, it stayed at .833. So I tried entering .380/330 next to them and the fcm said invalid entry. I tried entering /330 and it took that. Eventually it accepted the .830/330 entry but it then changed to a IAS speed instead of Mach. And then the progress page had my ETA at one of my waypoints being 1135z while my destination ETA at 0630z? How can that be? So I have certain waypoints in the legs page on the NATs show .830/330 and some showing 297/330. And my PROG page ETAs are bouncing all over the place and it showing a step climb one second, and none the next. And just going back and forth. And on page 2 till the last page of the legs page the speed/altitude entries are blank. I've never seen anything like this. I'm running p3d 2.5. Any ideas?

I took a video on my phone and uploaded it to YouTube. Notice how on the ND display the ETA is correct

 

http://youtu.be/s95XjUjjO60

Try entering .830 without the / at the end. I've found sometimes it doesn't accept the /. Try entering FL330 as 33000.

Obviously something is making the FMC screw up.

 

That point SLANY is where seems to start to go wrong because there is no data there at all on the legs page.

 

ai would try to skip a bunch of waypoints. Pit something near EDDM (your destination) after GISTY and execute.

Is the ETA in EDDM ok then?

 

Then re-enter SLANY and the other waypoints you erased in the legs page and see if it works then.

 

Also, if this was a one time only fluke, then I would not worry about it too much.

Sometimes things like that happen.

I had the whole sim freeze up the other day after I selected a certain approach, erased it selected it again, corrected it, skrewed it up, selected it again....then freeze.

This stuff can happen.

Thanks for the help guys. Towards the end of the flight the legs and PROG page went back to normal and ETAs were good. It was too late to try your suggestions as I already landed. I'm going to do another flight tonight and see if I can reproduce it or not, hopefully it was just an isolated incident, which I think it was

I've had issues like this due to having a waypoint on my route that has a duplicated name and the flight planner has chosen the wrong one. It's easy to have happen on a NATS flight because so much is not on airways. Your plan could have had you going to the wrong waypoint which is hours flying away. It may have been like that all along but you only noticed it when entering constraints. The FMC is doing it's best to make sense of the information that it has.

 

When things like this happens I alway try stepping along the route in PLAN mode because then it becomes immediately obvious something has gone wrong and where it is. I usually check my route before departure in PLAN mode anyway, but especially if I have entered the STAR when en route.

Like Kevin said... step through the legs if anything looks odd.

 

As for following Kyle's suggestions, the ".83/"  works everytime for me.  Usually I am entering ".84/330S" to force the flight level and speed I want across the NATS... gotta remember the S.  Also note that the T7 FMS will not accept a speed constraint without an altitude constraint.

Ok so I'm enroute now CYYZ-EGLL and played with the legs page. And I think not adding the S after the altitude screwed something up. But everything is working fine now. Thanks for the replies everyone