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DAL488

PCS V Speeds are always incorrect

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Frankly, this is not a big deal, because during the T/O the FO alwways calls out the V speeds that the FMC computes.However, I am finding that the the FO's PCS typically says V1 160, Vr 165 and I can't remember V2..... The FMC computes speeds in the 130-140 range.It's gotta be something I'm doing wrong with the FMC seup. As soon as I finish the walk-around (yeah, I actually do it using Active Camera), I setup the FMC: re-enter IRS position (cause the FO always puts in KSFO; can't seem to fix that one either...); enter flight number; load my FSbuild FP in the CO route and activate; enter reserve, cruise FL, cost index; enter flap 5 or 15; enter the departure runway. I then sit and wait for the PCS, before entering ZFW and MACTOW.Here are the couple areas where I think the issue may be:1. Should I ALWAYS use a flap 15 T/O? I typically use Flap 5 for <325K lbs and flap 15 for >325K lbs.2. Should I hold off on entering the depature runway?Thanks for any guidance.James

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Hello James,1. For the PCS, FS2Crew returns the V-speed information that is fed to it via the Level-D SDK. It's pretty simple. FS2Crew just displays the information it receives.2. What do you mean about holding off on the departure runway?Cheers,Bryan

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Well I have to agree with James. I have never gotten the speeds to match, no matter what I do. ?Tero

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Hello Tero,They match for me, so all I can say is keep trying :-)Bryan

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Hello Tero,Before the FO hands you the PCS sheet, make sure you have entered the Flap in the FMC.Try entering the ZFW in advance too.Remember, FS2Crew is just returning the information it reads via the Level-D SDK.There is always the possibility that your weight is out of the range that the Level-D 767 FMC/SDK can compute accurate V-Speeds for. So I might suggest lowering your weight.That's just a guess, though.Cheers,Bryan

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Bryan:The comment about weight might be valid. I just about always operate with ZFW's in the 255-280K range.I received your e-mail. Next time I fly, I'll report back. Might be a couple days.James

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Ok, just did a flaps 15 takeoff with a ZFW of 270.1. Speeds on the PCS were about 20 kts higher than the FMC.My next flight will be empty, with a ZFW in the 240 range. Will report back.James

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I just did another test to see if I could reproduce it.The V-Speeds displayed in the PCS are based on the ZFW and Flap entered in the FMC.In fact, if you change the ZFW and Flap value in the FMC while the PCS sheet is open, you can see the numbers change in real time on the PCS.It works for me.http://www.fs2crew.com/pcs.jpg-Bryan

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There has to be some kind of magic going on in some systems, because so far I've been unable to get the correct speeds. With the tutorial I always get speeds in excess of 160 kts.Tero

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Hello Tero,For the V-Speeds, the PCS is simpling displaying what the Level-D SDK feeds it.It's very straightforward. I'll ask Wade or Laurent if they have any ideas about this.Cheers,Bryan

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Yes Bryan I understand that already, but something in the process gets broken because for some users that doesn't work.Tero

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Bryan:Based on your screenshot above, maybe we should be entering the ZFW BEFORE we receive the PCS?I just did a flap 15, ZFW 238.3 T/O and the speeds on the PCS weren't even close to the FMC speeds.But just like you did above, I bet if I kept the PCS open and entered the ZFW in the FMC, the speeds on the PCS would probably change and match up with the FMC.Please confirm, ZFW should be entered before or after receiving the PCS?Thanks Bryan.James

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Yes,Enter the ZFW and Flap before you receive the PCS.I'm going to clarify this in the tutorial and manual.When the PCS sheet is open, you're right, you can change the ZFW and FLAP value in real-time in the FMC and see the changes in real-time on the PCS.Cheers,Bryan

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Guys,I don't have the tutorial at hand right now, and I can't remember if what you are saying somehow disagrees with it or not.But.What *is* important is that the user should be able to do things in a sequence where:- he will input everything else for the FMC, but not the speeds, because...- ... the FO will calculate the speeds, which will then be input in the FMC v-speeds (by the user), and these speeds SHOULD agree completely with the speeds that the user would get from the CDU if he just completed the preflight all by himself.The idea is to get the CORRECT speeds from the FO, in the form of PCS. Not the other way around, ie. that the PCS matches what the user would have gotten from the FMC. What stands in the PCS after speeds have already been received from the FMC has no relevance. The relevance lies in the fact that, like in real life, the V-speeds have to be calculated separately and the FS2C FO will do just that and display the V-speeds *beforehand* in the PCS and the user can then input those speeds for the FMC. These speeds should of course agree with that the FMC would give you in the first place.Teroedit: just re-read this thread and I think it's fairly obvious that the ZFW is the key here. The manual says to not input weights until after PCS received. If you do this, you will never get the PCS to display correct speeds, because as the PCS reads Level-D SDK, it cannot get correct speed information as the FMC does not have enough parameters to calculate V-speeds from UNTIL it has the ZFW input in it.Thus: ZFW and FLAP need to be set in the FMC before the FO hands out the PCS sheet. I'm not at home and cannot test, but I'm 99.99% sure that this amendment will fix this problem.

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Enter the ZFW into the FMC BEFORE getting the PCS Sheet, and your numbers should match.

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I agree with Tero here (unless i was bl**dy sure I would never disagree).I do my own PCS sheeet, so if I get the maths wrong I would want to cross check it with the FO PCS (none of us are infalliable)This FO is your major cross check, but for this he needs the ZFW.There for we need to enter it as part of the setup, not sure when this should be donr, but from reading Marcus's flow I would suggest just after you get the zfw from servisair.Chris

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That is correct, the ZFW and FLAPS fields in the in the FMC must be filled out prior to receiving the PCS to get accurate values.The manual and tutorial will be clarified in Update 1.ZFW and Flaps can be entered after receiving the loadsheet hard copy from the agent.Cheers,Bryan

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