I noticed this a couple of days ago... I will be at normal cruise altitude ie.FL320 to FL360 the bird will be flying along nicely and then will be like going on a roller coaster ride. I checked the trim setting and it will be set correctly for normal cruise flight but like this morning I stepped away for less than 2 mins and the bird decided to pitch up to over 5600 FPM ascent which caused the bird to stall. I went back and made sure the trim was cutoff and also checked to makre sure that the wing and engine anti ice were one. I was able to decend to 10000 ft got it back in level flight hit the CMD A button and the bird attempted to pitch nose high again. I turned off the aito pilot and FD and reingagued them with teh same results. Also the FMC told me that VNAV was disconnected. in the MCP window instead of it showing MACH .79 it had a b flashing beside the .79. you can look at the flight data here: http://www.deltava.org/pirep.do?id=0x9732c Just prior to reaching the BIL VOR which was the TOD this was whre the problems started

What modes was the autopilot in when you had your problems (i.e. what did the FMA say)? Did it start in FMC SPD and VNAV PATH and go to something else? What was your MCP set to?

Autothrottle on, LNAV,VNAV CMD A set which I was in straight and level cruise. I had adjusted the Altitude to the BOD to set up for arrival

Autothrottle on, LNAV,VNAV CMD A set which I was in straight and level cruise. I had adjusted the Altitude to the BOD to set up for arrival

You had VNAV, but what was displayed on the FMA? VNAV PATH, VNAV SPD, VNAV ALT, etc. What did the A/P think it was doing?Are you certain the A/P was still on when the upset occurred?

You had VNAV, but what was displayed on the FMA? VNAV PATH, VNAV SPD, VNAV ALT, etc. What did the A/P think it was doing?Are you certain the A/P was still on when the upset occurred?

I do believe it was. I will have to go back and recreate the flight to see what all was displayed at which point.

Let me ask this. I have FSPassangers installed and prior to all this activity it added a couple of lines in the Stations listing with no values, would this have impact on the aircraft?

I'm not a sim expert, so I defer to my more learned colleagues.

No problem sir

Have you got a Joystick with force feedback, or something wacky like that? It might be switching CMD A off.It happened to me once. Go for a up of tea, coffee, or something a bit stronger. Then relised the a/c artifical horizon is all over the place. But managed to save my A$$. :(

yoke throttle and peddles

Any chance you were using real world weather? In some cases without additional utilities missing reporting stating stations or errors can cause sudden headwind changes as you cross weather station reporting boundaries causing significant IAS changes and therefore pitch changes that can occur in a stall. Add-on weather applications can have a weather smoothing function.Once the erratic pitch changes occur the A/P will detect the corrections required are out of range and disconnect. In addition notes in one weather application installation include a comment on reducing the turbulence response in some PMDG aircraft models.Finally any detected movement of your controller pitch or roll axis if bumped or experiencing variation due to hardware noise can cause an A/P disconnect. Been there.

Any chance you were using real world weather? In some cases without additional utilities missing reporting stating stations or errors can cause sudden headwind changes as you cross weather station reporting boundaries causing significant IAS changes and therefore pitch changes that can occur in a stall. Add-on weather applications can have a weather smoothing function.Once the erratic pitch changes occur the A/P will detect the corrections required are out of range and disconnect. In addition notes in one weather application installation include a comment on reducing the turbulence response in some PMDG aircraft models.Finally any detected movement of your controller pitch or roll axis if bumped or experiencing variation due to hardware noise can cause an A/P disconnect. Been there.

As mentioned above, the sounds like a problem induced by wx data, are you using an external wx program?

that doe make since, but I was using Active Sky Evolution and thought I had the weather smooting turned on

I think it is in the ASE manual but check out what is has to say about aircraft sensitive to turbulence like the PMDG models it mentions.A separate but similar issue is the wake turbulence option in AES. Some turn that off. I don't know how well wing vortex dispersion for take-offs and landing by AI aircraft are handled regarding shifting by crosswind components. Just another turbulence issue to keep an eye on.

that doe make since, but I was using Active Sky Evolution and thought I had the weather smooting turned on

There is an option in ASE that saye something like control the wx directly (can't check the exact option right now). If you look at he comments when you highlite the option it tells you that this may not work for some complex aircraft add ons. Select the option above it. I tried this option and as warned got some unwanted results.