Plane trying to pitch and roll over, what do you do? (poll)

[201er]

You're flying an instrument approach at destination in IMC. Let's say weather is something like 600 Broken and you are descending through 1000ft when suddenly and without warning the altitude is going down fast, air speed rising, and the plane is rolling. Weather is otherwise smooth or you know it is going aerobatic beyond what weather normally does. Controls are heavy and only somewhat responsive. You need both hands to keep it steady so reaching for things is difficult and distracting. Other than trying to recover, what do you do?

Electric driven AI supports indication on vac AI.

Edited Wednesday at 02:09 AM by 201er

[201Steve]

I think I’d pick more than 1 of the options

[201er]

3 minutes ago, 201Steve said:

I think I’d pick more than 1 of the options

You gotta do something first and you might not get to everything. In what order do you go

[MikeOH]

 

1 minute ago, 201er said:

You gotta do something first and you might not get to everything. In what order do you go

Well, your choices don't cover that.

First, I'm going to override the AP in order to FLY THE PLANE.  I'm certainly NOT going to continue on to land in that state!

[dkkim73]

Of course maintain control. But machines are trying to kill me (again?!) so master is the most universal answer. 

Of course in my plane trim runs through AP so autopilot breaker/switch is a one stop solution also. But not sure that's in the spirit of the question. 

It could also be a man on the wing...

 

[Oscar Avalle]

Disconnect the autopilot, considering that the autopilot disconnect button is just on the joke.

full power and go missed to figure out what is going on.

[Ragsf15e]

OAT?

[Ned Gravel]

33 minutes ago, Oscar Avalle said:

Disconnect the autopilot, considering that the autopilot disconnect button is just on the joke.

full power and go missed to figure out what is going on.

+1

[PT20J]

Based on the choices presented, and the title and description, we will assume that it is a coupled approach and that the airplane is suddenly pitching down and rolling. We will further assume that the airplane is not physically broken (in which case you are dead) and that the errant behavior is due to an autopilot malfunction.

Keep manually overriding and continue to land: Bad choice since the autopilot will trim against your input and you will end up with full down trim which in my M20J I measured as requiring a 50 lb pull to maintain level flight.

Turn off the auto pilot: Best choice. Push and hold the disconnect switch on the yoke while regaining control and manually trimming and then pull the AP CB.

Shut the master switch: Overkill and you will lose navigation and communication and any electronic instruments. 

Shut off electric trim: Depends on the autopilot. On some, the trim CB only affects manual electric trim and not the autopilot's ability to control the trim servo. Also, it will only affect the pitch axis and since the airplane is rolling something else is going on with the autopilot.

Find and turn off a circuit breaker: As stated above, this is the terminal action to kill the autopilot after control is regained. But it is not the best choice for a first action since it will distract attention from controlling the airplane.

Note that on a GFC 500 with ESP enabled, if you get slow on approach above 200' AGL with the autopilot disengaged, the pitch servo will engage and push the nose down. Unlike the deadly Boeing MCAS, it will not run the trim servo, however.

[201Mooniac]

In the most recent GFC 500 AFMS, the procedure is:

1. Firmly grasp the control wheel
2. Press and hold the AP Disc/Trim interrupt
3. Regain control
4. Manually retrim
5. Pull the AP circuit break

[Mooney in Oz]

40 minutes ago, PT20J said:

Turn off the auto pilot: Best choice. Push and hold the disconnect switch on the yoke while regaining control and manually trimming and then pull the AP CB.

I have the CB red capped for easy ID.

Edited Wednesday at 03:40 AM by Mooney in Oz
I noticed Skip’s post too late, so I deleted my original post.

[CL605]

I know many on this board have gone through scenarios like this dozens of times in full motion simulators. Hopefully they will chime in. FWIW, the technique I have been taught year after year is as follows:

1. Fly the approach with your hand on the yoke and your feet on the rudders. The pitch and roll described in the original post didn't happen without discernible movement from one or more primary flight control surfaces.

2. At the first sign of the AP not doing what it should be doing, disconnect it.

3. If you have both uncommanded roll and nose low attitude, correct the roll issue first, then pitch and power as you approach wings level. 

4. If you are nose high, correct pitch and power first, then correct any roll issues as you approach level flight. 

The autopilot is your best friend... right up until it is not.

[toto]

This discussion seems mostly to be about autopilot behavior and management, but the one time this happened to me "for real," it was a runaway electric trim with the autopilot off.  A quick thumb movement to trim forward on the yoke-mounted trim switch, and suddenly the plane was pitching down as fast as the trim motor could spin.  I was in the left seat, and it took all the strength that two of us had to overpower the trim while the right-seat person got the CB pulled.  It .... sucked.

[PT20J]

If the trim system is part of the autopilot, the yoke mounted autopilot disconnect will disable the trim servo. So, for any uncommanded pitch, even with the autopilot off, the first action would be to press and hold the disconnect button. On airplanes with manual electric trim and no autopilot, runaway trim will require turning off a switch or pulling a circuit breaker.

[toto]

4 minutes ago, PT20J said:

On airplanes with manual electric trim and no autopilot, runaway trim will require turning off a switch or pulling a circuit breaker.

I owned a Piper with electric trim and no AP, and it had a large "Electric Trim" on/off button right in front of the yoke with an integrated CB.

[toto]

9 minutes ago, PT20J said:

So, for any uncommanded pitch, even with the autopilot off, the first action would be to press and hold the disconnect button.

The runaway trim event that I experienced was a really long time ago in a C182RG - I vaguely remember fiddling with the AP disconnect switch while we were both hauling back on the yoke, but I don't remember much about the installed equipment.  What sticks with me was how fast it happened and how much force was required to overpower the trim.

[IvanP]

Sounds like A/P malfunction while flying a coupled approach. With my old KFC 150 system hitting the A/P disconnect on yoke and turning off the electric trim switch would release any interference from the A/P and trim system on the controls which should allow pilot to manually correct the attitude, retrim and continue the approach if the plane responds appropriately to pilot's control input.   

Other A/P systems may require different actions. I am not a big fan of coupled approaches, though. I like to feel the controls when getting close to the ground.

If the plane fails to respond to the above steps, then ice or some other mechanical failure of controls comes to mind. Not much you can do about that at 1000 ft above ground except trying to use all your force to keep the shiny side up and try to land.

Edited Wednesday at 05:03 AM by IvanP

[Pinecone]

You have to fly the airplane.

But while doing so, you can also hit the AP disconnect.  That is why it is on the yoke and easy to get to.

If you van maintain control, I would still land.  If I am fighting it and deviating, I may go missed, but do you really want to fight it for a whole approach.

CB and master and such are only if you are under control and have time.

[EricJ]

What are the assumptions?    Is there an autopilot engaged?    Do I have an ejection seat?

These things matter. 

[M20F]

Pull the chute!

[Skates97]

14 hours ago, dkkim73 said:

Of course maintain control. But machines are trying to kill me (again?!) so master is the most universal answer. 

Of course in my plane trim runs through AP so autopilot breaker/switch is a one stop solution also. But not sure that's in the spirit of the question. 

It could also be a man on the wing...

 

[toto]

2 minutes ago, Skates97 said:

That looks way less scary in the screenshot than I remember it being at full speed

 

[dkkim73]

24 minutes ago, Skates97 said:

You got the reference!

[dkkim73]

1 hour ago, M20F said:

Pull the chute!

Go to the back of the line with all the plastic airplane people!

[DXB]

The setup of the survey is too vague to discern any meaningful discussion topic or learning point  here.