This is my first intercontinental flight.I am flying from Gatwick, London to Boston, US.I setup everthing up and setup crusise level to FL450. But I got a message in the FMC that the max was only FL344 ...OK..so I setlled for FL344. But then.... after I climbed to around FL200 or so...I got a message saying that the max is FL240. I have LNAV and MNAV on and the MCP altitude is set to 34000Any Ideas why?I took a screenshot. but the Page memory is now .98GB and it wouldn't open any application for me to paste the screen capture. I am like 30% on my trip and don't want to stop it.MannyOK.. It froze on me.But I got the screen capture.

Hi Manny,You want to may be consider setting an initial cruise toward the lower end of the altitude buffet. This aircraft may struggle to stretch straight to its max FMC recommended cruise altitude.Perform a methodical step climb to achieve the best economies of scale. Thats if I've understood your question correctly.And just a friendly reminder - hope you've revised your altimeter setting to STD.- Jay

Jay, I think you are right.Its cause.. I have full fuel. The margin between overspeed and stall speed is very narrow at FL340.Hmmm... Interesting.Manny

No -400 route I know of requires full fuel; even the 14hr ORD-HKG (UA) or SFO-SIN (SQ).As a guide; for domestic flights the FAR requries as a minimum BURNALTERNATE 45MIN RESERVER And for internationalBURNALTERNATE10PCT OF BURN30 MIN HOLDING AT 1,500FTHope this helps

Hi,In addition to what's be said - I notice that your Autothrottle is not armed as well....I get exactly the same problem every now and then. The autothrottle disengages itself (sometimes seems to coincide with increasing the sim rate) and then i get the max alt fl 240 message.Weird? I always find that the autothrottle will not arm after selecting it to do so. I have to go into the failures menu, set the A/T to failed, apply it, set the A/T to working and rearm it and it works a treat.Just my 2c worth...Carl

jsut a quick note on the FMC. You should always aim for the FMCs OPT altitude..this will give you the most fuel efficient flight level for your current weight. Your pretty stocked up on fuel so whatever the OPT altitude of the FMC is i would reset my cruize alt to that.

Manny,before you start a flight I strongly recommend you to get through ALL manuals( especially cruise and fuel planning) since it seems that you are not very familiar with the 744.You would never take 100% fuel from Gatwick to Boston nor would you cruise at FL450 cuz this is even outside the operation limits.Nevertheless, the FMC should not give you a max alt of 24000 ft even if you have 100% fuel + max payload and also there should be an AT mode announced in the PFD while your AT switch is in armed position (if you take a close look at his screen you will see that the AT switch is truly in the armed position). Therfore, this has to be some kinda bug, try to reinstall the queen and see if things get better.