I came across this video this morning, https://www.youtube.com/watch?v=AqySqT0MHCw
- the stall break happens just before 2 minutes. I'm posting the video here because I've read on this site that Aerocommanders are known for their stability and benign handling. That view is reiterated in the comments to the video. One says the stall wasn't too bad, others ignore the video and recite "Aerocommanders are docile," and one says he had the same experience in a 900.

I'm not attempting to impugne the reputation of the airplane, I've never flown in one. The stall shown doesn't seem benign to me. What's the range of experience here? Do people who train in simulators stall the real thing from time to time?

Ashley

????

About like my first stall in a -35.

It's hard to see for sure, but it looks like the ball might be slightly off center just before the break. It doesn't take much of an uncoordinated situation to cause a break like that. Plus, I didn't think it was that bad of a stall break.

Also understand that you don't generally fly turbine aircraft to a full break like that. I've never done a full stall in any checkrides that I've taken, but I've only done a checkride in the MU2. You start recovery as soon as stall warning system goes off. In the case of the MU2, that was the stick shaker.

I had a 500B for 15 years and used to go out and stall just for fun all the time. Mine always stalled like the one in the video too. The AC has tons of rudder authority so there was never any doubt I could keep it from entering a spin but it definitely would drop a wing like that every time. The 500B was the only airplane I stalled for about 15 years so I kind of forgot how other airplanes behaved until I got the 425. I went out and practiced full break stalls in that and what a difference. No wing drop, no drama. It just kind of mushed along like you would expect in a 172. I loved how the AC flew especially how it would fly well slowly. There was plenty of warning before the stall so it would be kind of hard to inadvertently get there. But if you held the yoke back and got it to fully break it did always drop a wing and want to spin.

Thanks for the perspective. There was a relatively short interval between the horn and stall, but the instructor had commented that speed was decaying quickly and later said it was about 6-9 knots ahead. He also commented there wasn't much buffet before the break.

Ashley

PC12 stalls are pretty sporty:

https://m.youtube.com/watch?v=VNRK2aUmWWI

Yikes. So, impossible to stall and keep the wings level??

This looks like technique error, at as you approach stall, your ailerons are neutral and you need to use the rudder to stop the wing break.

I learned my basic PP air work in a Luscombe, famous for dropping a wing....
If you did not have the ball and stick centered precisely the luscombe would flip over on its back so fast it would make your head spin...

My dad made me do stalls in that airplane for hours, until I could do 20 or 30 in a row both without dropping a wing... dancing on the rudders...

Yikes. So, impossible to stall and keep the wings level??

That does seem more dramatic than one would expect for what is supposed to be a really docile low wing loading airplane.

What was the power setting? Having power on will increase bad stall behavior (like the PC-12 video shows). The torque of the engines plus the swirling prop wash create imbalance between the wings.

I was surprised at the short time between warning and break.

Did anyone else feel like the altitude was too low to be doing this stuff? Looked like only 2-3K above ground level. I could not make out the altimeter, so this was just looking out the window at the ground going by.

Take note of this:

https://app.ntsb.gov/pdfgenerator/Repor ... l&IType=FA

The private pilot, who was the owner of the airplane, and a flight instructor were performing a recurrent training flight. Radar data showed that the airplane departed and climbed to an altitude about 5,000 ft above ground level. About 5 minutes after takeoff, the airplane conducted a left 360° turn followed by a right 360° turn, then continued in level flight for about 2 minutes as it slowed to a groundspeed of about 90 knots, which may have been indicative of airwork leading to slow flight or stall maneuvers. The airplane then entered a steep bank and impacted the ground in a nose-low attitude.

Did stall practice at 5K AGL and hit the ground. I would be very careful doing this stuff low to the ground *particularly* for power on stalls.

Mike C.

They entered the stall at 9600' MSL and lost 400'. No idea what the AGL was.

That's exactly what I was thinking. Someone earlier mentioned the PC12 only stalls like that power on. Power off is more conventional. Is that because of the torque at high power? If so then why don't all SETPs have stick shakers and pushers? Or is there something about the PC12 that makes the power on stall particularly exciting. Not trying to turn this into a "bash the PC12" or "twins don't do this so they're better" conversation. Just trying to understand why. As for my 425 power off is a total non event but I have always been too chicken to do a power on stall at full power. It could be just as bad.

105" prop and 1000hp does that. It would need very large tail surfaces to have authority to cancel that much torque. The tail on a PC12 is full of all sorts of aerodynamic gimmicks to keep it at least somewhat stable, and even then handflying it without the yaw damper is not fun.

I'm in Paul B's camp, not that dramatic, and maybe a little quicker on the top rudder would have kept it from going all the way to what...45 degrees?
I have had wilder rides in a Baron... not like a Baron gets out of control, but it unloads quickly.

Lots of factors.

High torque. At full power, the PC-12 is putting out 3700 ft lbs torque. That is about 370 pounds more lift required on one wing versus the other

Prop slip stream. It spirals around the fuselage, tail, and wings leading to different aerodynamics between left and right sides of the plane.

Prop lift. Due to high attitude, prop is carrying some of the aircraft weight. At 20 degrees nose up, prop is lifting 6% of the aircraft weight. This plus prop wash lift on the wing allows power on stalls to be much slower than power off stalls. Slower means more break and longer recovery.


Because the PC-12 is unique in the torque effects. The TBM is less horsepower and higher RPM which leads to about HALF the torque, and thus quite a bit less to worry about than the PC-12, though it still does have a reputation for torque roll. The cost, weight, and safety factors of a stick pusher are significant, so better to not have it if you don't need it. The PC-12 needs it to keep pilots away from the stall.


425 torque is a third of the PC-12. Having two engines also doesn't put the torque on the aircraft center line which partly cancels some of it.

I would be careful with power on stalls. Lots of ways that can go bad in high power turboprops.

Mike C.