PMDG 747-400X - problems in FMC VNAV page

[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

[downscc 1,327]

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?

[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

[Guest kelvind80]

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

[downscc 1,327]

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.

[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

[cavaricooper 2,615]

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 |

[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