"UNABLE CRZ FL" message

[mozart 1]

My A340 is happily cruising along at FL380, the FMCG confirms "OPT FL392", and I have no altitude constraint programmed for the next 600nm. At the same time, the max. N1 indicated in the engine window display mentions "CLB", not "CRZ" as one would expect.Why? Anything I am doing wrong, any way to fix this?Lastly, how can the fuel and ETA calculations be soooooo far off? I did LSZH-VHHH, FSBuild calculated a flight time of approx. 10h40, taking into account ASV weather. Fuel approx. 85 tons.In flight, I get complete rubbish indications: during climb, the ETA indicated implies a flight time of 8 hours. Expected FOB at destination: -135 tons (note the "-"!). Interestingly though, I don't get a "not enough fuel" alert. At about 8 hours in flight, the indication is perfectly alright, I'll land after about 10h 45mins with about 6 tons FOB.What is going on there? Is the arrival time and fuel consumption calculated off KIAS? Obviously, if I cruised at 330kn at FL390, that would be more than Mach 1 , in any case way outside the performance capabilities of the plane. At that speed, I'd agree that I can do the trip in 8 hours and that I'll use all that fuel. Doesn't the FMCG anticipate that I'll be going to cruise at much higher altitude and at M .78? It has that information stored, so why isn't it used when calculating landing FOB and ETA?PS: not a topic for the Airbus forum, but just to let you know that I am having a heck of a time with your 777 and 757. The 777 was a really frustrating experience in the beginning and I thought "PSS is dead", but guys, you turned it into a marvel and the 757 worked great right from release.

[Guest vrandar]

It sounds to me like you might not be entering the correct ZFW and block fuel into the MCDU (the INIT page 2)as part of your MCDU preparations. This would account for your minus figure in the expected FOB. The FOB should never show minus at any stage of the flight.Rob Elliott, EGPE InvernessPSS Airbus Support andAirbus Fleet Training Captain, British Airways Virtual airbus@speedbirdonline.co.ukhttp://www.speedbirdonline.co.uk/airbus.htmlhttp://www.bavirtual.co.uk

[mozart 1]

>The FOB should never show minus at any stage of the flight.I certainly agree with that ;-)>It sounds to me like you might not be entering the correct>ZFW and block fuel into the MCDU (the INIT page 2)as part of>your MCDU preparations. This would account for your minus>figure in the expected FOB. Actually I know for a fact that I do. Also, the calculations "become right" during flight - it's only during the initial phases of the flight that they're completely off!