Cessna 206 crash Lloydminster sept 8 2024 final report

[cjc]

https://www.tsb.gc.ca/eng/rapports-repo ... c0095.html

[pelmet]

Basically, a steep turn at low level leading to a stall at an unrecoverable altitude. There were cameras on board including a video camera which from what is stated, was able to see elevator deflection. Yet the report does not state what the estimated maximum bank angle was(or state that they were unable to determine this).

I find the TSB reports frequently lacking in info. Would be kind of nice if I could read these reports in advance and make suggestions(not likely but PM me). If we knew that the pilot banked at a certain very steep bank angle at low altitude, it might be a judgement issue. On the other hand, it happened to be technically considered a steep turn but only around 40 degrees bank, there might be more of a hands-on flying competence issue.

These accidents happen every so often. I knew a highly experienced guy who died in an aircraft doing the same thing. Lots of power is usually good in a steep turn.

[CpnCrunch]

It's pretty easy to calculate. Looking at the area on google maps shows the diameter of the previous turn was 210m. According to google AI that will require a 57 degree bank angle at 90mph. Checking with online bank angle calculators show a similar 57 degree angle.

The report says that the fatal turn was steeper than this one, and they interpolated the stall speed to be about 60mph at 60 degree bank and 10 degrees of flap. (I'm not sure how accurate that is, as you can't really interpolate stall speeds based on flap deflection, but it's all we've got).

So it's pretty clear that the pilot was banking much too steeply without understanding the aerodynamics on the entire flight.

[Bede]

This crash devasted me. I taught the observer to fly as did my wife. He was friends with my kids. He had fantastic hands and feet and a super nice kid. I'd like to think that had he been the pilot flying this never would have happened. He started at the company as a high school student sweeping the hangar floors to pay for flying lessons. Eventually earned enough money to get himself a CPL. Such a waste.

I worked for the company over Covid. Their flight ops was super safe. Every flight planned out with a formal risk assessment (given the low level flying they did). Probably the best employer I've worked for. (Obviously got paid less than flying a 737, but got paid well and didn't get nickel and dimed.)

Everyone wants to look for systemic factors to make sense of a chaotic universe. Sometimes there are no grander answers than someone made a mistake and people died.

[digits_]

Note that it is perfectly possible to do a 1g turn with 70 degrees bank angle, if you sacrifice some altitude.

Also note that we are talking about a Cessna 206, not an airliner. A very responsive airplane where bank angles can change rapidly if initiated by the PIC.

I don't think the exact bank angle in the turn makes a significant difference to determine what happened. 40 or 70 degrees, it was unfortunately mismanaged.

500 hours is not much. I would be very curious to know what the low level training at the operator covered. And how experienced the training pilot is/was.

[CpnCrunch]

Note that it is perfectly possible to do a 1g turn with 70 degrees bank angle, if you sacrifice some altitude.

Sorry, just updated my calculation. It's definitely 57 degrees. It was me confusing diameter with radius at one point, and all the online calculators agree.

But yes, it's definitely possible to do it at 1g, although not at 200-300AGL.

It's interesting doing experiments in FS2020 flying up narrow box canyons in the beaver or whatever, and cranking it around with partial flaps while descending.

[digits_]

But yes, it's definitely possible to do it at 1g, although not at 200-300AGL.

Not for the full turn perhaps, but allow me to clarify. The report and some replies above seem to imply that if the 60 degree level turn stall speed is 95 mph, and you're turning at 40 degrees bank angle at 90 MPH and the bank angle inadvertently hits 60 degrees, that you would stall.

That's not necessarily the case. I find it much more likely that if you intend to turn at 40 degrees and the bank angle unintentionally hits 60 degrees, that you've likely dropped the nose in the process as well, and that you won't be stalled at 90 MPH. Now if you overreact and then yank the nose up, then yes, you'll stall and spin. But the bank angle in itself is not a major factor. How you're dealing with things, is. I doubt this incident happened in a stable level turn.

[CpnCrunch]

Not for the full turn perhaps, but allow me to clarify. The report and some replies above seem to imply that if the 60 degree level turn stall speed is 95 mph, and you're turning at 40 degrees bank angle at 90 MPH and the bank angle inadvertently hits 60 degrees, that you would stall.

That's not necessarily the case. I find it much more likely that if you intend to turn at 40 degrees and the bank angle unintentionally hits 60 degrees, that you've likely dropped the nose in the process as well, and that you won't be stalled at 90 MPH. Now if you overreact and then yank the nose up, then yes, you'll stall and spin. But the bank angle in itself is not a major factor. How you're dealing with things, is. I doubt this incident happened in a stable level turn.

But, if you look at the previous turn, the *average* bank angle required was about 57 degrees (if speed was 90mph and diameter 210m). So, that means it couldn't have been done anywhere near 40 degrees. It wasn't inadvertant.

I suspect just a combination of "its worked before" and just not realising the risk. It's not going to suddenly fall out of the sky if you hit 60 degrees, but maybe a combination of steeper than normal turn, slight climb, reduction in airspeed, etc. Maybe just too long flying right at the edge of the envelope, and this one time went a bit too far beyond it.

[‘Bob’]

Yeah it’s perfectly possible to go even knife edge and not stall.

But you’re not recovering before you hit the ground if you do it at 300 feet unless you were climbing when you initiated it.

It’s likely they were already descending due to the loss of lift from the bank angle, and rather than fix the problem by immediately rolling wings level the pilot chose to pull harder and stall it.

RIP to all