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Guest DanEvans

PMDG 747-400X - problems in FMC VNAV page

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Guest DanEvans

Hi,I'm having huge problems trying to program the FMC. I am following Craig Read's EGLL-KLAX flight tutorial, but I always hit a brick wall with an error on the right hand side of the VNAV page. Consequently VNAV and LNAV won't arm. See pic for details. Pax. wt. 21881kgCargo wt 33389kgZFW 233974kgT/O wt. 385943kgFuel 151969kgFlaps 20V1 152Vr 168V2 179I've got no idea what I'm doing wrong to cause the error. Any help will be much appreciated. cheers,Dan

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What I see on the attched pic is an INVALID ENTRY message and know idea what you are tyring to do.This page also indicates that an AT OR ABOVE 3000 at a fix cannot be achieved by the VNAV profile, but that shouldn't prevent VNAV from arming. It's not unusual to get this on departures with contraints. We had a thread last week on this subject with a couple of workarounds (I use VNAV until accelerated to flaps up speed then LVL CHG to climb above the constraint - works every time, and there's other ways to do this too).Anyway, back to the issue: What are you doing that gets the INVALID ENTRY message?


Dan Downs KCRP

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Guest DanEvans

Hiya,Thanks for the reply. I was trying to input different cruise speeds to try and remedy the situation hence the "invalid entry" message. The legs page was programmed for a BUZAD3J sid out of EGLL, rwy 09R, which worked out ok. This sid has a 6000' altitude restriction at DME30 BIG until the BUZAD intersection itelf unless atc say otherwise.It seems that the error is linked to the cruise speed. I used a cost index of 90 as recommended in the tutorial.Cheers,Dan

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Guest kelvind80

What is the value you're trying to enter into the cruise speed?Kelvin

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Changing the cruise speed shouldn't change the altitude constraint problem. In the real world, if you couldn't make the constaint safely then you would tell ATC and request a lower. They are used to heavy 747s. However, in all the cases I've experienced I have been able to use pilotage to overcome the FMC's econ profile safely. By the way, if you can use flaps 10 instead of 20 your climb performance will improve.


Dan Downs KCRP

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Guest DanEvans

Hi, again and thanks. After looking at the PMDG manual, I remembered what I did to get the "invalid entry" message. I was trying to input the speed restriction of 250/FL100 under "SPD REST" and I wasn't sure how to enter it. The manual doesn't seem to mention the error I managed to get.CheersDan

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Try 250/10000.........does it take? Why are you entering a restriction other than the standard 250/10000 here? Should you want to change speed (in the climb mind you) you can always go SPD INTV. Also, re. cruise speed and cost index- entering one obviates the other- i.e.- no point in CI if you designate cruise speed.Allow the FMC to build the plan, ensure your waypoint alt restrictions are correct and execute- that's it. Once enroute, you can ask for a speed waiver (usually granted without any fuss in the UK) and then simply go into the VNAV CLB page and DEL the 250/10000 that automatically populates in the FMC. EXEC that and you're done!Select proper THR modes based on departure weight and you should be all set- at lighter weights she makes all the marks with proper T/O derates and CLB-2 and even at MTOW she flies all EGLL SIDS correctly in CLB.Best-Carl F. Avari-Cooper BAW0225http://online.vatsimindicators.net/980091/523.png| XP Pro SP3 with FS-GS System Unification | 2 x APC UPS | Coolermaster Stacker 830 SE | Asus P5E-Deluxe (X48) | e8500 @ 4gHz | Tuniq Tower 120 | EVGA 8800GT 512MB | Sony 40" Bravia XBR | 2 x 1 GB Corsair XMS2 | 500GB Seagate Barracuda 32MB SATA2 | Corsair HX620W PS | CH Products Yoke-Pedals-Throttle Quadrant | Aerosoft 747MCP-EFIS-EICAS |


Best-

Carl Avari-Cooper

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Guest DanEvans

Hi all,Managed to suss out why lnav and vnav wounldn't arm - I hadn't engaged the flight director!! Still you live and learn. Thanx for all your help.Dan

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