FMC doesn't set automatically Takeoff V1, VR, V2 speeds

[Guest Andrea]

Hi PMDG,in Takeoff Ref page of FMC it doesn't work automatical the V1, VR, V2 takeoff speeds setting. After flaps degree setting (10) nothing happens pressing FMC 1R, 2R, 3R with left mouse button.Andrea

[greggerm 312]

This happens to me whenever I do not have a departure runway selected. I believe the FMC requires the runway information so that the length and altitude can be factored into the speed calculations.Check to be sure you've got that runway entered... Of course, if you DO have the runway entered, I'm at a loss..-Greg

[imoore 1]

Hi Andrea,Also be sure that you have all your weights set up on the (I believe) Init Ref page. Without that info, the FMC can't compute any speed at all.Basically, be sure that the FMC has "Preflight Complete" displayed.

[jacsantos 0]

It also doesn't compute those speeds if you set a much colder OAT other that the actual in the derate n1 selection page. You have to keep ZFW GW OAT and the runway within published values in order to the FMC fill for you. Jos

[Guest rcarlson123]

Strange ... I never choose my departure runway until I'm actually given my taxi clearance by ATC (I fly on VATSim exclusively) yet I never have a problem with the FMC auto-calculating the V-speeds. The FMC does clear them out though, once I do select a runway, so I just click the LSKs again to recalculate them. Most likely his problem is due to incomplete weight data.