I've had SU2 on a few flights and seen a few wierd things happen.* On a flight from ENHD to ENBR I was loaded up with zero payload and 9000lbs fuel (1k/7k/1k) and the FMC refused to calculate the available fuel for the last few legs of the flight plan. For those familiar with the area, the route was RWY32 -> LUCKY4 STAR, basically clim right out and turn onto the STAR at 15000ft, and descend through the star and a nice ILS. It showed 8.2k lbs fuel left at LUCKY and then 0.0 for the remainder legs for some reason. Reserves set to 3k lbs.* On a flight from ENBR to ENAL I had loaded zero payload and 14k fuel (2k/10k/2k) and set up a fairly straight forward trip was planned, departing north, climbing through VOO and straight for RWX-25 at 15nm for joining the ILS. The FMC insisted my optimum altitudes for the various bits were around FL1125, which I found to be a slight problem, as I had not nearly the fuel needed to get there :)Any pointers on what more info you may want to figure out whats wrong?

Alex,don't have SU2 yet, but 1 small observation that may help you.Standard Fuel loading on the 737 is to laod the Wings first, with the remainder in the centre.This would mean that for flight 1 you would have 4500/0/4500and for flight 2 7000/0/7000Hope this helps.

I'm curious how much fuel to you end up with at ENBR.The FMC is not really computing optimal altitudes in SU2, so I wouldn't put a whole lot of faith in the altitude it computes.Lee Hetherington (KBED)http://www.precisionmanuals.com/images/betaimg.jpg

It's not MUCH! Sure it's about 54 miles but just try putting 1/7/1, I do not think any 737 would place this tiny amount and certainly not setup this way. There is no OPT/MAX in SU2, TRIP alt is generic........[h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/betaimg.jpg

Yes, when I tickle my brain I actually know this. Just never came around to think loudly enough about it. :)

OK, but still, trying to tell me FL1152 for my legs are a but off the chart, unless your first name is Neil and your neighbours name used to be Robinson. :)

I know, I just loaded it quickly to have a little run. Just don't tell my local AAIB/NTSB :)Anyway, I just reflew the route, ENHD-LUCKY1E-ENBR and the problems regarding the VNAVN DISCONNECT it reproducible (so either im persitantly doing a bad thing, or something else goes wrong). A few more notes:Took off on RWY14 this time, set up for CRZ at 15000 and joining LUCKY1F at LUCKY, and passing through it through to RWY17 at ENBR. I added fixes at KRM142/5, KRM220/5, KRM300/5 to make sure I had plenty path for the climb before joining the STAR.Climb out in good time for passing LUCKY at 15000 (ALT contraint set no LEGS page), and VNAV will disconnect after passing 2500ft due to UNABLE CRZ ALT, even though im level at 15000 over a minute before passing LUCKY.After passing LUCKY level and nice it will actually allow itself to be reengaged and then continue to descend through the STAR and join the ILS, although the path draw for joining the ILS contans a cusp and is not a smooth continuous turn.After passing LUCKY it will suddenly compute fuel for the remaining legs correctly too.But make no mistake, SU2 is also real nice, plenty of nice stuff, and it's very smooth in handling it when I try to set it up for bad approaches, and it captures everything nicely.