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Guest dt1951

Simulation Rates

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I am having a problem with the 744 and 744F LNAV when I put the simulation in half-speed mode. Yes, I did a search for this and didn't find any postings that addressed this particular problem (the search was on "simulation rate"). Here is my scenario. For a medium size flight (in the 7-9 hour range) I start and fly it in normal speed for a few hours until it's time to go to bed. At that time I disconnect from Vatsim and put FS in the half-speed mode prior to going to bed. When I get up the next morning I find the aircraft is only part way through the flight and is heading in the opposite direction of the one shown in the FMC.As a sanity check during pre-flight, after entering all the flight plan data into the FMC I go to the legs pages to check for discontinuities and that the legs all point in the direction I need to be going (i.e., I have no rogue waypoints taking me 5000 miles out of my way).When the above situation happens I look at the FMC legs page and see that there are no obvious reasons for this behavior. There are still more waypoints in the LEGS page so I know I have not gone past the last one in the FMC. So something is causing FS and the aircraft to get screwed up.

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I've just had a similar half-speed experience. Flying EGCC-KJFK. During the descent it was teatime so I set the sim rate to half speed to give me more time to eat before flying the ILS. When I got back to the flight deck the Queen was flying around in graceful circles, miles off the flight plan with LNAV still lit on the MCP. I clicked LSK1 on the FMC and she obediently flew direct from her position to the next waypoint.But that wasn't all. After landing (routine man land with AP and A/T disengaged, and FD off) I briefly got a GEN warning for engines 2 and 3, and the APU wouldn't start. The switch clicked round to 'start' and back again but nothing happened, even after waiting a long time.Framerates on the ground during rollout and taxi in all view modes were down to approx 10 per second. Up until then I had been getting 19+ throughout the flight, regardless of view.On exiting FS9 I got an error message indicating that it had hung and wouldn't exit.My system is a P4, 3.2 GHz (or thereabouts) with a gig of ram. I don't have any extra video cards or anything installed.I can only assume that half speed did something nasty to the Queen and/or FS9.Rob

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I too am having the same issue....for the past three days I have been trying to fly PANC-RJBB...I follow the checklist and procedures all the way up to cruise alt to the letter....then I fly through about the first hour on 1x and everything is fine, then I switch to 1/2x and go to bed....when I awake in the morning, the queen has made about 30-40 circles over various waypoints, and has also dropped altitude and once was flying at over 500kts....there is another post with someone with similar issues regarding the LNAV, but so far I haven't found any solutions to this(other than flying at 1x and changing the setting to pause at TOD to prevent from running out of fuel)My system is Dell XPS 420, Pentium Quad Core 3.25Ghz, 4GB RAM, GeForce 8800 GTX.-Aaron

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Awhile back, someone posted that FS should be paused before invoking Time Compression or Saving. Never tried this so can't say if it works.Alex Reid

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I'm soooo tempted to say that these are jets which are designed to go fast, and you're not supposed to fly them half-fast, but I won't...

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Ok gents heres what I usually do:Check the FMC progress page 1 and get your ETA to the destination. Bring up the clock and subtract the time the clock says from the ETA to your destination.Lets say you have 8 hours to go. Subtract 1 hour from that to allow for the descent and theres how much sleep you get.

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Or, you can use the PAUSE Before TOD feature.This way you can take your nap or do your chores and when you come back she is either enroute or paused about 12 nm before TOD waiting for you to start your descent.The simulation is designed for x1 speed, although it will tolerate 0.5 to 8x for brief periods there is just too much going on in the modules that is time dependent and tuned to have fidelity with the real aircraft to hope for successful time compression/expansion.

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