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BlazzerOne

777 autopilot/control problem

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Hello, I've just bought the 777 base back at aerosoft.com. I have a big complicatet problem, i try to tell what happens. When i start a flight with the 777 (with fmc etc.) all is great. Then i take off and and fly a bit manual later on i put on the autopilot and i engage LNav and VNav. The plane is following the route and climbs. But at one point the problems are starting: First I get a CabinAlt waring with 999999 ft. 30 seconds later i get something like a autopilot disagree so the ap, Lnav, Vnav is engaged but the plane slowly starts getting off the route, accelerating and do what it want's. At this point I switched AP modes to heading select, speed and alt hold. Still no reaction from the plane. Now i disangaged the AP and the aircraft starts spinning in the air like it has a million tons of cargo in its back. There is no control at all it just spinns around.

 

Need help! I spended 80€ and now i can't do a simple flight

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First I get a CabinAlt waring with 999999 ft. 30 seconds later i get something like a autopilot disagree so the ap, Lnav, Vnav is engaged but the plane slowly starts getting off the route, accelerating and do what it want's. At this point I switched AP modes to heading select, speed and alt hold. Still no reaction from the plane. Now i disangaged the AP and the aircraft starts spinning in the air like it has a million tons of cargo in its back. There is no control at all it just spinns around.

Sounds like a bad experience. :vava:

I have no serious explanation except that perhaps someone in the back of your plane hacked the FMCs in flight with a PS4 via WLAN and secretly changed the variables from binary to hexadecimal or something of equal extent. B) 

But the impact of the underlying error ("But at one point the problems are starting") is so huge that its reason might be easy to find because of its fundamental nature.

Do other planes behave normally or is it just the T7?

 

Sorry, but I have no clue. Anyone else?

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I have Windows 7 Professional 64bit. Did anything. I try to make a youtube video of it, that you can see what exacly is happening. 10 min ago I took the T7 for a test flight around EDDM, I did one  pattern with LNAV/VNAVand an ILS approach anything worked fine. I did a go around after that I controlled the AP with Heading select, Speed and V/S or Alt Hold. it worked 5 minutes but then I got the Cabin Pressure warning (again 999999ft) Autopilot has done what he wanted and then I turned off the AP and the aircraft startet spinning in the air and was uncontrolable

 

Lucas Geyer

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I'm getting an issue similar to this as well

 

I was just doing a flight took off AP set, then about 5 min later the plane started making right hand movements off the LNAV course, Yoke starts to do stutter/freeze motions then the acft starts to spin/jump on the spot at different angles then falls from the sky. I never noticed a cabin pressure issue.

 

Im also using windows7 64bit. FSX

activesky Next

I have all run-times installed and even UIAutomationCore.dll

 

at first because I did a fresh install I thought it might have been because I was missing UIAutomationCore.dll as it happened on an earlier flight but it still occurs even after I put this dll in to flightsim.

 

PC Specs

i7 4790k 4.0ghz overclocked 4.6ghz
Maximus VII Hero Z97 LGA 1150 motherboard
EVGA Geforce GTX980 ACX 2.0 Superclocked 4GB
G.SKILL TridentX 16GB (2x 8GB) DDR3 2400MHz
850W 80 plus gold PSU
S840 evo 500GB SSD, - for FSX only

S840 EVO 120GB SSD  - Main C drive

+ 2TB STD HD

Noctua NH-D15 Multi-Socket PWM CPU Cooler

 

Just a note this is only happening to me on the 772LR, haven't flown the 773 to see if its on both

I also run Windows mode

 

Robert Fluke

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So I just replicated the same flight again and this time it got a little further down the road before it started to yaw right.

 

I switched of Autopilot and no matter what I did it wanted to yaw right on top of this the yoke was jumpy and no longer smooth despite the high frames.

 

I even disconnected from activesky to correct the plane but it still wanted to yaw right.

 

Here are some screenshots I took just before the problem and during the issue if it helps:

 

2015-12-31_21-49-17-121_zps9cxao1ax.jpg

 

2015-12-31_21-49-28-970_zpscyehzxkv.jpg

 

2015-12-31_21-49-29-914_zpsu0nwcsfr.jpg

 

2015-12-31_21-49-52-254_zpsrqnpl67n.jpg

 

2015-12-31_21-50-11-646_zpsv6extini.jpg

 

2015-12-31_21-50-17-725_zpsbolzkpbr.jpg

 

2015-12-31_21-51-5-329_zpsyh0zi0ri.jpg

 

What usually happens when its had enough fighting it just hits a wall and bounces around before falling out of the sky

 

2015-12-31_21-52-36-196_zpsqwjk9kzy.jpg

 

My CG is all correct so I dont think its a balance issue

 

Robert Fluke

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Its hard to see but what is your TAT? It looks like +7C, which at 26000 seems a little warm causing loss of engine thrust, airspeed and control.  Maybe not.  However, the airspeed should stay within a few kts of commanded in this mode of flight.

 

What about panels?  Are you starting from a saved flight?  If so, maybe something in the saved flight panel is corrupt.

 

Also, I don't see any yaw. The slip/skid indicator is solidly centered, you are simply rolling. Helps to understand the difference.

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So I just replicated the same flight again and this time it got a little further down the road before it started to yaw right.

Hi, Robert,

 

In addition to Dan's suggestions (especially the one about starting from a saved flight), do you

have any failures active? Also, what does the main overhead panel look like? Any illuminated

buttons?

 

Mike

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Sorry yes the plane rolls right not yaws.

 

It does make subtle movements right first before it rolls over, maybe thats why I thought it yawed

 

I wondered about the temp thing as I found it weird that it was in + degree when my activesky conditions for certain altitudes showed -

 

I do have a saved load up to the main screen for when FSX starts but that's the Default cessna to my closest airport, nothing saved as in to go to flight.

 

I checked all failures are off. I will have to watch the overhead if it occurs again as I didn't actually bring it up sorry, but I get no warnings

 

I will try an run with Anti virus off (I only use the avast freeware) and see if this could be blocking the info provided from Activeskynext.

 

Funny thing is it doesn't happen to my other Payware planes (non-pmdg)

 

Here is a more higher res image

2015-12-31_21-50-11-646_zps8tturtwt.png

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I do have a saved load up to the main screen for when FSX starts but that's the Default cessna to my closest airport, nothing saved as in to go to flight.

So just to be clear, you start up with a brand new setup at a gate every time? What is your

startup state? Is it a custom one that you created or one that comes with the 777?

 

Mike

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So just to be clear, you start up with a brand new setup at a gate every time? What is your

startup state? Is it a custom one that you created or one that comes with the 777?

 

Mike

 

Affirm, start up with brand new setup each time, no saved flight

 

But fingers crossed, Im 20min into redoing previous flight I did yesterday (from scratch) when those crashes occurred and so far so good.

 

Im now at cruise, 37000ft,

NZAA to NCRG

TAT -16 (Still doesnt look right to me)

 

Was a little nervous on climb as there was a bit of turbulence and couldn't tell if it was happening again or just the sim.

 

 

So onto the issue and what I found were 2 problems but hard to tell which was the culprit.+++2008 x86 was faulty and not installed to the correct position (the one I had installed, to my F drive?) So i uninstalled and reinstalled to the latest version I went and got, so this could have been it?

 

Other issue after installing +++2008 I satrted up a new flight and noticed an issue with my controller (Logitech Extreme3D pro) pulling acft right on taxi or in slew mode, uninstalled reinstalled, re calibrated and as I said so far so good.

 

Will advise if flight is successful or not in about 3 hours

 

Robert Fluke

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Ok so the flight was a success looks like it was (most likely) the visual runtime causing my issue.

 

Lets hope it is no longer an issue for future flights.....

 

Sorry to Hijack your OP Lucas, I just thought my issue was similar.

 

Robert Fluke

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TAT of -16 isn't too far off. At Mach 0.8 you can expect -26 for an ISA day so -16 represents ISA+10.

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Ok so it happened again but through sheer coincidence I think I might have found the real culprit to my issue.

 

Doing my current flight (today) flying NSFA - NZAA, Weather was good (despite a hurricane in the area near Fiji), everything looked normal then passing 18,000ft the plane again rolled over on itself to the right then did some weird rolls/jumps

 

I paused the sim, checked the overhead and nothing was illuminated, while I received no warning notices.

 

to stop this since I was unable to control the acft, I decided to just reloaded/re-selected the same plane/livery on climb, reset the fmc etc and despite a little teething I was again tracking as normal until....

 

I was switching on DATA, POS buttons to which I hit the TERR button on the PNF side and bang it started making those jerky moves to the right and rolled over to which it then proceeded to flip and skip in the air

 

I turned it off and was able to get control of the plane this time.

 

Switched AP back on after getting back to normal conditions, hit the TERR button again on PNF and the plane started to jerk to the right,

 

I turned it off before it started to roll over and it went back to normal..

 

Programs I had running at the time were:

ASN

VPilot(flying online at the time)

 

On the previous flight with no issue I may not of had the TERR button activated but I can't be 100% sure, but I know it was active for the initial part of this flight before the issue hit again

 

I guess to be 100% sure I need to complete other flights with TERR active then if it starts to roll over switch it off to see if this is truly the culprit

 

Robert Fluke


So im still in flight and decided to test it again and if I hit the TERR button on both the left and PNF side the plane will start to make its jerky movements to the right, once I switch it off problem stops!

 

Robert Fluke

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TAT of -16 isn't too far off. At Mach 0.8 you can expect -26 for an ISA day so -16 represents ISA+10.

ISA+10 at FL 370 would mean OAT of -48°C (ISA OAT @ FL370=-58°C).

My rule of thumb was that with climbing through FL280 an OAT of -40°C (=-40°F!) would be equal to standard and the higher you get the smaller should be the difference to ISA temps. 10°C of difference at FL370 is IMO an indicator for high altitude hot air updraft (moisture), which is "normally" followed by an intermediate (but probably severe) downdraft (cooler air) when "on top" of the cell (air mass effect).

 

Maybe there are some severe updrafts/downdrafts below the OP's routes going on which cause the A/P to react strange and gets the A/C out of control when trying to fly it manually?

Probably turning on FSX's thermal visualization could show the updraft and prove that problems start when entering that zone.

 

BTW: on the OP's screenshots in post #6 there are quite some CUs/CBs during climb on his route and below him. In the end on the last two screenshots the sky is perfectly blue. Maybe just a WX simualtion flaw with an abrupt change of values?

 

Happy new year,

Claus B)

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ISA+10 at FL 370 would mean OAT of -48°C (ISA OAT @ FL370=-58°C).

Indeed, but OAT is not TAT.

My rule of thumb was that with climbing through FL280 an OAT of -40°C (=-40°F!) would be equal to standard and the higher you get the smaller should be the difference to ISA temps. 10°C of difference at FL370 is IMO an indicator for high altitude hot air updraft (moisture), which is "normally" followed by an intermediate (but probably severe) downdraft (cooler air) when "on top" of the cell (air mass effect).

 

Maybe there are some severe updrafts/downdrafts below the OP's routes going on which cause the A/P to react strange and gets the A/C out of control when trying to fly it manually?

Probably turning on FSX's thermal visualization could show the updraft and prove that problems start when entering that zone.

 

BTW: on the OP's screenshots in post #6 there are quite some CUs/CBs during climb on his route and below him. In the end on the last two screenshots the sky is perfectly blue. Maybe just a WX simualtion flaw with an abrupt change of values?

 

Happy new year,

Claus B)

FL280 would an OAT of approximately -40 deg C (-40.44 in fact) but your rule of thumb makes no sense. For an ISA+10 day, OAT will be 10 deg C above standard day for all altitudes a 777 can operate at. Your first sentence contradicts your rule of thumb too.

 

I've no idea whether thermal effects are simulated in FSX at that altitude, but PMDG recommend switching them off anyway.

 

Anyway according to the OP's post (above yours) his problem is related to having the TERR display active on both sides, so not weather related. In my experience the TERR display seems to increase VAS usage so having it active on both sides could be a big hit and might cause problems with the sim. Not sure why you would have it switched on at that altitude though.

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