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Guest k7kdh

Unable Cruise Altitude 747-400 Fmc Msg.

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Hi all, Hope all is well.It has been some time since i flew the 747-400x. As soon as I set down it was just like an old pair of shoes,"comfortable". Flight from KSEA to KLAX, " I've flown this "landing on 25l" In LA Many times. It's time for take off, Flaps at 10 , 80 knots then 150 , up I go. after 800 ft agl. I hit vnav but it just flashs,"White on the screen". FMC msg says, "unable cruise altitude". In the past it has worked flawlessly .It has done this before but I don't remember how i fixed it.Any help??? The fsx 747-400 is the 2.10 update current latest and greatest. Thanks and Happy NEw Year 2009 Kevin Hite AMT

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It means that it is unable to climb to the altitude set in the flight plan. You may need to change the loading of the plane or select a lower derate thrust so that more power is available for the climb. Check the legs page of the FMC and see what the altitude are set at. Any that are in strong/bold type are required to be met or you will get the message you get.

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On departure, unable cruise altitude advisory might be due to an "at or above" altitude constraint in the departure procedure (SID). As I recall, there are several of these at KSEA such as at or above 3000 some distance from the runway. In most cases, even at MTOW, the 747 will easily clear these constraints but the FMS isn't aware of that yet for whatever reason. Most of the time you can clear the message and keep going. On occasion there could be a constraint that is going to be busted, and in the real world ATC expects to be advised of this. In the sim world I put her in LVL CHG after acceleration altitude and IAS is okay and let 'er rip instead of climbing in econ mode.

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On departure, unable cruise altitude advisory might be due to an "at or above" altitude constraint in the departure procedure (SID). As I recall, there are several of these at KSEA such as at or above 3000 some distance from the runway. In most cases, even at MTOW, the 747 will easily clear these constraints but the FMS isn't aware of that yet for whatever reason. Most of the time you can clear the message and keep going. On occasion there could be a constraint that is going to be busted, and in the real world ATC expects to be advised of this. In the sim world I put her in LVL CHG after acceleration altitude and IAS is okay and let 'er rip instead of climbing in econ mode.
Thanks for your replies Friends. As for procedures I was a little rusty. I found out what happened!. The Route KSEA-KLAX had a route discontinuity on the LAX end. I had to manualy remove and reinsert the Arrival. I have the cycle 805 installed. The discontinuity was right before 25L it was heading to the left to ZUSGI 33-48-27.410N 118-26-42.580W," which may be missed approach", instead of inline with 25L. Also the route was not complete from Departure 34R KMORE to BASET THREE Arrival. After this was completed the VNAV was operational. In the past and perhaps with a different Air cycle installed the route was flawless each time.. Kevin Hite AMT

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