I'm not feeling the love for 4.6. As often as not, autopilot will completely flip out on me, and I mean barrel rolls and an unrecoverable dive of doom. This isn't so much an FMC issue as a WTH issue. From time to time it will wander off and explore territory away from the flightplan, too. But this is just craziness.

My confidence in the autopilot for a three or four hour investment of time is at an all time low. This is the third time today, and my scheduled "play day" is blown without a single landing. Reliability covers a multitude of sins.

UPDATE: The FAA has issued an emergency airworthiness directive grounding all 757s until the autopilot problem is resolved. This after two 757 crashes in as many days. This affects all CS 757s installed on my computer.  As real as it gets.

Tim, Looking at the QRH, there is a full page of information and procedures to follow after the loss of AP, in flight.
First, go to the instrument source select switch and select ALTN.
Place both pilots' HSI range selectors in same position
If left FMC failed, select Right AP or center. Leave Vnav on to have AT.
Some notes about ATC.....

If both FMC fail, it becomes Complete FMC Failure.

In that case, use VOR, DME and ADF , Radar to navigate on raw data.
Plot and do position update as needed to maintain correct ground track.
If this fail, ask ATC for DF steer
Use heading select mode and raw data on HSI display.

The B757 is one of the most reliable and safest plane. Mine is anyway !

Happy Flying !   8-)

Raymond    Boeing or nothing
KFLL     South Florida

I've only had it happen to me once on the CS757 v4.6. A reinstall using the repair option fixed it for me straight away.

I'll reinstall and see if it helps. I'm wondering, could the joystick contribute to such behavior? I keep my joystick calibrated, but something weird is going on with it, because when I slew, the airplane isn't still. But keep in mind the autopilot doesn't go off, it just violently flips out.

Thanks for the info about the autopilot failure, Blover, but it's hard to find the right page when you're barrel rolling in a dive!  ;D

UPDATE: I reinstalled per Mark's suggestion. I also examined my joystick. I have a Logitech 3D which has served me faithfully, but is really sloppy now. I found that the sensitivity was at the max, and null zone at the minimum. I using slew to experiment with different settings, I finally arrived at settings that were less sensitive. I don't know if that could have anything to do with my problem, but anyway, it is a lot better this way.

So I had a wonderful scenic flight up Central America from Bogota, Columbia to Mexico City, Mexico. The 757 performed perfectly (except for the no T/D issue). So whatever the issue was, apparently it's fixed.

Mine went nuts last night on a flight from KATL to KLAX.  Running at 4x speed once I reached cruise at FL380, after a while it went totally out of control - roll, pitch, yaw went completely bonkers, and IAS dropped all the way to zero....no way to recover, all on board perished in the crash.  :'(

Maybe this plane becomes unstable at 4x speed or above?  I had no such problems with the CS 767 from KLAX to KATL the other day, also running at 4x while in cruise.

I don't trust accelerated time at all due to similar experiences. Do I remember reading somewhere that Captain Sim does not recommend the use of accelerated time? But what you described is exactly the problem I had (without accelerated time).

So many variables! But if the 757 does as well as it did last flight I may never fly anything else  :)

I agree with Tim. I never use a simulation rate above normal with the Captain Sim 757 or 767!

I found it fine in a straight line, but even at a sim rate of 2x, they get very wobbly when there is a bend or turn in the route. The more the accelerated time, the worse the trouble.
It's okay IF you return it to normal before the bend/turn, but if you miss it...well you know what's gonna happen! :D

SWA4420 wrote on Nov 28^th, 2013 at 5:23pm:

Maybe this plane becomes unstable at 4x speed or above?

For some people it is not even stable at normal time. Anything above normal and you are just asking for trouble.

Michael Cubine

I was having problems flying from KATL to MYNN.  The 757 4.x became unstable and uncontrollable during the climbout.  I had "Active Sky Next" running and I am wondering if the 757 Captain 4.x does not respond will to the weather conditions fed in from Active Sky and the like.

I use Active Sky 2012 and it's (the CS 757) fine with that. The only CS aircraft I flew when using the trial version of ASN, was the 777, and until I used easy settings, it was a difficult flight. Be aware that the problem was had by my other addon aircraft with ASN too, which made me decide not to buy it (for now).

I will say last night I tried the CS 757-200 with Active Sky NEXT (KTPA - KDFW) and also found very strange behavior that led to discontinuation of the flight. Nothing seemed significant about the whether, but It was up and down, and even overspeeding. Nothing like I've seen before, which makes me wonder if it was the weather.

I completed the same flight with another 757  :-[ in the same weather without difficulty.

One time does not a conclusion make. But we'll see. Active Sky NEXT is a great, innovative product, but can be VERY aggressive in its depictions of turbulence. It will be interesting to see if other  reports come in from ASN users.

I seeing the same thing with ASN usually when turbulence is present. The rolling parameters had to be tweaked down to make the 757/767/777 to fly well, with ASN increasing the intensity of these effects, these params may need to be tweaked down even more.

Using REX here, I'm half way across the pond from JFK to EGLL at FL410 (way too much chop on Eastern seaboard today).  I just heard my stick shaker going nuts and found the trim all the way up.  I did enter a stall and went to down FL360.  Now I cannot seem to accelerate beyond 180 indicated.  Set altitude to FL350 in a slow descent now building speed back up.

Here we go ahead again, this time, I see N1 is at 0%.    I wonder if my throttles are fighting each other (ch yoke and go-flight throttles).

fuzzy11 wrote on Dec 26^th, 2013 at 7:13pm:

Here we go ahead again, this time, I see N1 is at 0%.    I wonder if my throttles are fighting each other (ch yoke and go-flight throttles).

I'm not sure why the N1 is 0%, but I often disable my the joystick after activating the AP (CTRL+K (default)) with most aircraft. I resort to using the keyboard and mouse until the final approach phase of the flight. This prevents the joystick from interfering with the AP during the climb/cruise/descent phase of my flights. If you saw the problems that the MS Sidewinder FF2 was giving me, you would probably wonder why I'm still using it! Don't worry, I'm planning to get a new one soon.

Hi Folks: I have had the exact same issue the last few days. I hadn't flown my trusty CS 757 in a while, so two nights ago I set up a flight from CYUL to CYHZ. I used ASN for weather, FSX in DX10.
About 10 minutes into the flight the plane became uncontrollable - violent pitching and rolling,  in auto or with the AP off, eventually crashing into the ground.
I repeated the flight again last night using a well known 737-800. No issues,  lovely flight (lousy landing but that was my fault).
I redid the flight again tonight once again using my CS 757. Once again, at approximately the same time frame, the plane became almost uncontrollable. At this point, I shut down ASN and started up OpusX which I also have. The 757 settled down and flew correctly. I changed ASN settings from realistic to easy, shut down OpusX and restarted ASN. The plane became violently pitching and banking again - but not quite as bad as previous. I shut down ASN, and restarted OpusX, and the remainder of the flight was fantastic.
To the great relief of the deathly ill passengers, I nailed the landing (calm winds always help).
It appears to me as mentioned previously that ASN does seem to dislike the CS757.