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billyguo

All about 744

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1. After startup all 4 engines by normal procedures, I check the flight controls system in secondary EICAS STAT page. Sometimes I can see the Outboard Aileron comes up when I move. But sometimes they don't. Why? 2. After your engines have stabilized at about 70% of N1, hold a moment then press To/GA button. What exactly the "moment" is. Cause if I hold the "moment" for a little longer then press T0/GA , I'll get "Takeoff speed Deleted" in CDU, and "No VSPD" also in PFD.

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"1. After startup all 4 engines by normal procedures, I check the flight controls system in secondary EICAS STAT page. Sometimes I can see the Outboard Aileron comes up when I move. But sometimes they don't. Why?"Can't think of any reason why they shouldn't.. unless you have engine and demand hydraulics switched off? Outboard ailerons are locked out at high speed and when the flaps are up (in the air), but this shouldn't affect what you see on the ground."2. After your engines have stabilized at about 70% of N1, hold a moment then press To/GA button. What exactly the "moment" is. Cause if I hold the "moment" for a little longer then press T0/GA , I'll get "Takeoff speed Deleted" in CDU, and "No VSPD" also in PFD."I forget the precise logic for this happening, but this message may be being caused because of a large fuel burn between the time you initialized the FMC (with your weights and fuel) and takeoff time. I don't know why you are getting this just because you waited a few seconds to hit TOGA (maybe the fuel burn during engine stabilization is just enough for the FMC to think there is something wrong between what you initially entered and what the FMC is seeing now). I've never seen this on any of my sim flights, so maybe it's a timing issue. Pilots normally enter their V speeds very close to departure time.Hope this helps.Cheers.Q>

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In response to your first question, I have noticed something along those lines occurring with my 747 Queen of the Skies. When loading a flight with all engines running and all hydraulics normal (sometimes I'm lazy), I will notice either in the EICAS Stat Page or from an outside view that the left outboard aileron is in a slightly down position while the right one is in a neutral position. Neither will move with a control yoke input until you lower the flaps one notch. If you retract the flaps, all outboard ailerons will still move when you test the controls. Weird bug maybe?As for your second question, I always let the engines stabilize around 70% for just a few moments (about 5 to 8 seconds maybe) to make sure all engines are stable (we don't want to veer off the runway during takeoff with asymmetric thrust),and then hit TO/GA. I've never had my V-SPEEDS canceled on me yet so I might try holding 70% for a while longer and see what happens next time I fly.Kim


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"I'll get "Takeoff speed Deleted" in CDU, and "No VSPD" also in PFD."Ah, I assumed your V speeds would disappear with the appearance of these messages.Sorry, I'm out of my depth here, regarding both anomalies.Cheers.Q>

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Guest neerajpendse

I have seen the first anomaly too ... ! Sorry no answer, but I guess I am not the only one. After a while things were OK, and as I recall that was after flaps were set to takeoff position.Someone?- Neeraj

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1) It's probably just a bug. Pretty minor, anyway.2) This is more serious, and has happened to me several times. Up until now, I haven't been able to figure out what the trigger is. I wonder if one of the PMDG guys would please comment on what might cause "Takeoff speeds deleted" to occur when TOGA is pressed??Thanks,- Bill


- William Ruppel, CYKF, VATSIM 816871

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For those of you that have the second problem, can you reproduce it?


Mike Roth

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Looks like I need to make a correction... The Big Boeing FMC Users Manual mentions a Takeoff Speeds Monitor, but the trigger is 3rd engine start. If a change in conditions modify the calculated speeds by more than 2kts (at 3rd engine start), the speeds will blank (and, presumably, the TAKEOFF SPEEDS DELETED message will appear).Q: Does this 3rd engine logic persist until the aircraft leaves the ground?It also has the line..."Changes in runway condition, gross weight or planned takeoff flaps clears any manually entered or prompt selected V speeds."Are they talking about manual entries for these values, or, in the case of aircraft with Weight & Balance computers, sensed Gross Weight? (Fuel burn changing the weight of the aircraft).I recall that the logic for the message was programmed in PMDG, but how the programmers interpreted the logic, I'm not sure.Hope this helps.Cheers.Q>

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About the outboards not moving, I notice it always unlocks after I start setting my flaps. I've never checked if it's still unlocked if I pull up the flaps.About the VSpeeds deleting, I just had that problem for the first time just a little while ago when I took off from SFO. I did change runways from 28R to 28L but reconfirmed the speeds. I throttled up to about 70% N1 and then hit TOGA. I didn't notice anything until after I was in the air. The VSpeeds still showed up though.Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg


Ryan Gamurot
 

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