I was just approaching Rio De Janeiro and something strange occurred. As I was levelling of at 3600 for an ILS approach to runway 10 I started to gain INSANE amounts of speed.....340, 350, 360 etc etc etc. Then next thing I am gaining altitude like she wants to land on the moon. Everything was as required. Done this before! Any thoughts?

I was just approaching Rio De Janeiro and something strange occurred. As I was levelling of at 3600 for an ILS approach to runway 10 I started to gain INSANE amounts of speed.....340, 350, 360 etc etc etc. Then next thing I am gaining altitude like she wants to land on the moon. Everything was as required. Done this before! Any thoughts?

 

I've had a few similar experiences while cruising. Then instantaneously overspeed with speeds you quote, and then it recovers. I've also had the opposite where I've got low speed warnings out of the blue while also cruising nicely. I've put it down to weather change issues in REX for now, so haven't brought it up.

It went nuts on me too.   I was flying Tutorial 1 through FMC control.   First it started to veer off course when I tried to correct it went into a steep dive.  I would get it stable, put it back on autopilot, again a steep dive.  I fought it for 10 minutes or so and then gave up. Is there anyway to shut off the autopilot / autothrottle alarm.   I acknowledge with the master alarm button but this wouldn't shut if off.   I would always have to put it back on autopilot/autothrottle to shut the alarm after which it would go nuts again.   There was no way I could tell to fly it manually without the alarm driving me nuts. For the most expensive add-on I've ever purchased...it's really, really disappointing.

Sounds like weather engine spiking to me...

Sounds like weather engine spiking to me...

 

Yea that's what I've been assuming. Thank god it doesn't happen in real life, it really freaks me out! :ph34r:

I'm not sure what you mean by "weather engine" but I did not have ANY weather programs running and, as per the Tutorial 1 instructions, I had stock FSX clear skies with no wind.  This morning I loaded a route that I had created in NGX FMC.   It flew fine from KSEA to KSFO, again with clear skies and no wind, until somewhere on the STAR at which point the autopilot and autothrottle stopped tracking the FMC .  Even a simple hold heading, hold altitude and hold speed would not work with the autopilot/throttle.    In this case I was able to turn off the autopilot/throttle and it's warning alarm and was able to manually land.

 

I'm running on a new system I just built running Windows 7 64 bit, Hazwell i7-4770k overclocked to 4.4 GHz, ASUS Maximus VI HERO motherboard with ASUS GTX 780 graphics card and 8 Gigs of ram.

Sounds more like your hardware was overriding the sim A/T.  You can change this setting in your PMDG options. With the default setting, if you don't reduce your hardware throttle to idle prior to descent, it will force the sim throttle to wherever your hardware is (because the autothrottle mode in the real aircraft would allow that).

I think I've solved my problem.   On the PMDG site there was reference to a similar situation by a customer with the B 747.   The response was that it might be controller (joystick, throttle etc) noise.   I don't remember the technical reasoning but anyone interested can go to their site..   I removed a USB hub that all of my controllers were connected through and connected all of them directly to the USB ports on the PC.   I also, recalibrated all devices.   I've now made one fully successful flight and I'm in the middle of another this no problems of any kind.   Seems like this was the fix.  Thanks