Spiny Norman said:

This video popped up in my YT feed no doubt because of the recent Learjet crash.
There’s a pretty reasonable chance that they suffered from tail icing and hence loss of control.

YT

FWIW I’d pre-programmed myself if that ever happened to anything I was flying would be to stop trying to fight with the elevator and to use the elevator trim system.

So instead of the relatively small elevator trying to pitch the plane up & own I’d use the entire horizontal stabiliser instead. It’s difficult to get fine & rapid control like that but it’s the only control you’ll have.

And indeed I did have to do that one night when descending into Archerfield Airport near Brisbane. The Metro 2 turboprop I was flying had no autopilot so it had to be hand-flown 100% of the time. When I tried to pitch down a little to start the descent the elevators refused to move. So yeah that was a bit of a problem.
But I just used the elevator trim to start the drop and I had some time to see if I could figure out what was going on. I then remembered read a report on a Beechcraft Kingair where it’d been sitting out in the rain on the ground for a few weeks and when it was flown after a while when climbing the controls froze in position, but came back when they descended again. After some investigation they found that the water drains in the bottom of the fuselage where blocked with debris and the bottom of the floor had enough water in it so the control cables were covered and when the water froze they jammed. And this Metro had also been sitting in the rain for a few weeks in Bankstown.

So that’s what I reckoned was happening. I had plenty of time before needed to land and if the elevators didn’t free up I could have diverted to Brisbane with its very long runway and just trim the thing onto the ground. A couple of minutes after flying around in lower altitudes the elevators freed up again so I was able to make a normal landing. After I got out I went under the fuselage, poked all the drain holes, and water ran out of them all for several minutes.

I figured the icing over the control cables was the problem and that was that. I flew back at a lower altitude where it was warmer and the freezing problem didn’t occur again. I left a note for the next pilot that was going to fly it in a few hours later that day and also wrote it up in the maintenance logbook.

Gosh!

That’s a very serious incident!