Hi, folks-I've run into a strange problem that I need your help with. I've done a search in the support forum and didn't see anything like this, so maybe it's particular to me?I used SU1 normally without any problems that weren't well known. Since updating to SU2, however, both of my engines shut off randomly, sometimes a few seconds into taxi, and sometimes several times during taxi. They have not shut off in flight yet. What's particularly strange about this is that at the same time as the engines shut off, my flaps retract two slots. If they were at 5, they retract to 1. If they were at 1, they retract fully. This happens every time the engines shut off at exactly the same time as the shutoff. The flap movement is uncommanded.I even had them shut off just after I pressed TO/GA- when I restarted them, they were still in TO/GA mode and accelerated immediately!Starting the APU and restarting the engines works normally, but they enventually shut off again.When the shutoff occurs, I am operating no switches at all- frequently just taxiing straight down a taxiway.I tried starting a new flight with the default Cessna, switching to the 737 and starting from there, but the same thing happens. I'm pretty sure my configuration is normal- I've flown hundreds of flights before SU2 without this problem, and I'm a stickler for accuracy. My fuel load is normal (almost all my flights take place with empty center tanks and mostly full wing tanks- for example, my last flight was 5075-0-5075) and the wing fuel pumps are on with the center fuel pumps off.Any ideas? Here's my setup- FS2004, CH FlightSim Yoke USB, FDC, RCv3, ActiveSky, FSNavigator.Thanks,-Simon Binder

hmmm, weird problem this one.Just as a test, try disconnecting your yoke and use the keyboard.ScottYBTL

I think, and I may be wrong, that the NG has an automatic flap retraction mechanism if the engines shut off. As to your other problem...no idea.

SimonJust a thought - try running without Radar Contact. I believe I read somewhere that this problem has been reported before.Bud

>Just a thought - try running without Radar Contact. I believe>I read somewhere that this problem has been reported before.Good suggestions- they led me to the ultimate solution. By eliminating add-ons one at a time and taxiing around KATL, I discovered that the problem was....the mixture control on my yoke. It turns out that even though jets don't have mixture controls, the PMDG 737 will shut down if the mixture is slid to off. I had been leaving the mixture slider closed, and each time the yoke jiggled the control "read" the position, sent the info to FS and the 737 reacted by shutting down both engines. Once I slid the mixture control to full open, the problem went away.So- if you have a yoke with a mixture slider, make sure you leave the mixture open!Thanks for the help, folks!-Simon

Great to hear Simon.I tend to leave my mixture and propeller levers in the full on position when I am flying jets. Glad you are flying againScottYBTL

"I think, and I may be wrong, that the NG has an automatic flapretraction mechanism if the engines shut off."This is the same bug I reported recently, Fred. It's related to the loss of hydraulics. It's definitely not real world behaviour ;-)With the engines not running (assuming the APU is not running also), there will be no hydraulics (see previous message thread re engine windmilling not providing sufficient engine driven hydraulics for all aircraft systems which use hydraulics). Without engine or APU generators, there will be no electrically-driven hydraulic pumps either or power for electric motors to drive the T/E flaps. Standby Electrical Power is not powerful enough to move flaps.Cheers.Ian.