TOC always defaults at 280 Kts. How to change it?

[Gigabyte 0]

Hi,I've been a registered user to PSS aircrafts for a long time and never had significant problem or ones that could not be fixed one way or another.One thing that I can't figure is the way I can change the auto inserted TOC speed in FMC, which always defaults at 280 kts. If I change it manually using the MCDU it reverse to the previous value.Is it possible somehow to remedy this? In particular for the short flight I am doing these days, I need it to be 250 kts.Thanks in advance for any suggestions and help.Gig

[Guest vrandar]

Can you provide a bit more info here please or a screenshot of what is happening on your MCDU. You can always put in speed constraints at any point in the flight, but I am puzzled as to why you would want to be at 250 kts at TOC. At TOC you will be presumably be at a relatively high flight level and if that is over FL290 you will in any case be using mach rather than IAS as your indication of speed.Rob Elliott, EGPE InvernessPSS Airbus Support andAirbus Fleet Training Captain, British Airways Virtual airbus@speedbirdonline.co.ukhttp://www.speedbirdonline.co.uk/airbus.htmlhttp://www.bavirtual.co.uk

[Gigabyte 0]

Hi Rob,First of all thaks for responding.I agree with you totally if I were not doing a very short flight, 25 minutes or so. In a real life is done mostly with B737 and they climb no more than around FL160 because, among other factors, they woudn't reach cruise altitude and would be forced or directed by atc to start descending.So is a short flight, altitude 16000 feet and if I am not wrong, although over FL100/250 Kt speed restriction, Radar Contact doesn't allow me faster cruise speed. I know there are ways to set RC not to pay attention to speed restrictions, etc. But I don't want to do that.The problem is that I can't set the auto inserted virtual waypoint "TOC" speed restriction to 250 kts. So after overflying FL100 it starts accelerating to 280 kts and I have to disengage managed mode and set the speed manually to 250 until cruise level. As I say if I change the speed on the MCDU from 280 to 250, it reverts to 280 after about 2 seconds.Here are the screen shots of init and fplan pages:Thanks again,Gig

[Guest vrandar]

I do not have RC so can't comment on it. Unfortunately in the PSS Airbus it is not possible to set a speed constraint at TOC, so all I can suggest is that you insert a PBD fix either at the TOC position or as close as possible to it. If you can't get one in exctly the same position then try entering one as close as possible before the TOC point and one as close as possible aftewards (1 mile would do)and set a speed constraint for each of them. Being so close the speed that the TOC speed of 280 that the Airbus computers are entering for you into the MCDU will be practically nullified.Rob Elliott, EGPE InvernessPSS Airbus Support andAirbus Fleet Training Captain, British Airways Virtual airbus@speedbirdonline.co.ukhttp://www.speedbirdonline.co.uk/airbus.htmlhttp://www.bavirtual.co.uk

[Gigabyte 0]

Hi Rob,I imagined that TOC restrictions couldn't be changed. I think it's in the manual, too. Just wanted to make sure there were no "backdoors" to change that behaviour ;) Your solution sounds clever and logic, so I'll give it a try.Thank you very much once again for your time and help.Best Regards,Gig

[Guest cobrafly]

TOP is a "psoeudo point" it can't be changed.according to your screenshot, you selected a CI=0 witch is the lowest the lowest cruize regime you can get.with CI=0, and CRZ FL160, the lowest managed sprrd you can get in cruize is 280kts, its computed by the FMGS according to your COST INDEX and according to your flight envelope at that altitude.( it's the OPT speed located at MID-POINT between VLS and VMO)in the real life, on A320, if we need to fly at 250KTS, we just select the speed on the FCU (we pull and turn the speed knobe)it's the procedure and nothing else.

[Gigabyte 0]

Hi CobraFly,Thank you for you response. That's exactly how I was doing and I'll keep on doing it that way because the other way suggested doesn't seem "comfortable" and and right in terms of flight management.Thank you everyone for your ideas and suggestions.Regards,Gig