'Speed Ref' Select Switch

[GAJ52 54]

I would like to practice some circuits in the 737-800.Is there any way to set up the FMS for circuit flying at an airfield, I am primarily refering to the FMS speed bug settings for both take off and landing.Secondly, I am able to manually select the V1 and VR bugs using the SPD REF select switch, but in flight the VREF bug will not change, it just stays at 80 ? Also the manual refers to BUG 5, what is this used for.Glen Coyne

[Guest wee_davie_2612]

Hello Glen,The way I'd set up circuits in the FMC would be to follow the normal procedure of setting up the FMS for a flight except that a route isn't entered. If you goto the DEP/ARR pages of the CDU and select only the runway for takeoff (i.e. no DEP route) and for arrival select the landing runway and a runway extension. The runway extension will add one waypoint to the route and cause the FMC to be ready with Vref speeds directly after takeoff.However I'd normally just fly it without touching the CDU's, simply using the SRS (Speed Reference Selector) to enter the speeds from charts.I too cannot set the Vref bug for some unknown reason, I'm sure that I used to be able to though. I'll start a new thread about it if I cannot solve the problem.As for bug 5, this cannot be set in the PMDG NG. On the SRS there should be another detent for bug 5 between the Vref selection and the Set detent which is missing on the PMDG rendition.As to what bug 5 is for, it is simply another bug that the pilot can set as he sees fit.Also note that the Set button in the PMDG version actually resets any entered speeds/weight.I'll try and figure out the Vref selection and get back to you.Cheers,David

[Guest wee_davie_2612]

Seems I was wrong about the SRS Vref selector ever working. I had a quick search of the forum and found that this issue has been around for at least a year.I doubt that a solution is being worked on, it's full steam ahead on the 744 at PMDG now I think.Maybe in the BBJ update it might be fixed :)David

[GAJ52 54]

David,Thanks for the reply.I too thought I had the VRef function of the SPD REF switch working in the past, but from your comments I must be mistaken.It looks like for 'touch and go's' I will have to do the landing flap settings on a piece of paper, and use the SPD REF switch for the take off settings.RegardsGlen

[Guest wee_davie_2612]

Hi Glen,Yep, that's what I did earlier today when testing out the SRS Vref function (or lack thereof).All you need is a chart of Vref Speeds and the flap limit speeds. If you need the Vref charts for the -7/8/900 I can post them here for you (the AOM I have doesn't cover the -600).Have a good one,David

[GAJ52 54]

>If you need the Vref charts for the -7/8/900 I can post them>here for you (the AOM I have doesn't cover the -600).That would be great - thanks, I normally fly the 800.Glen

[Guest wee_davie_2612]

Hi Glen,[a href=http://www.ibsw08346pwp.pwp.blueyonder.co.uk/vspeeds.pdf]Vref Speeds[/a] (made a .pdf of them, easier to share)Enjoy :)David