Caravan Crash Credentials Connundrum

[ocelot]

I don't come here anywhere often enough to participate in this kind of argument.

What I originally meant to say was that the crash didn't look like the well-known maneuver we often refer to as "SSCDD", but rather like an ordinary or garden-variety roll that for some reason (I guessed inability) was not counteracted. Apparently the exact wording I used caused Gabriel to become concerned that I was working from a wrong and thus unsafe mental model, and a lot of shouting ensued, and my attempt to clarify only made it worse.

Some points that maybe seem worth mentioning:

- When a wing drops in the SSCDD maneuver, it's because of unbalanced lift, which is the result of an asymmetric stall. It wouldn't happen otherwise.

- In a fully developed spin, both wings must be stalled because if only one was you'd be rolling uncontrollably over and over from the unbalanced lift and that's not what happens.

- In the case Gabriel posted about (stalling while in a slip with one wing raised) the high wing is at a higher AoA and stalls first, and the rest follows, as the accompanying video shows.

- In a turn, however, the low wing stalls first because the turn gives it a lower airspeed. The usual SSCDD maneuver involves turning with inadequate airspeed margin, so in that case the low wing drops.

- Inadequate aileron authority at low speed may be made worse by pulling up, but can be a thing regardless of AoA.

As I think I've posted about before, Popular Combat Simulator's flight models may or may not be accurate but regardless of that many of the aircraft the models represent (fictional or not) are extremely janky. There's one well-known warbird whose Popular Combat Simulator's model at least will fly off the ground at about 45 knots if you don't hold it down, but has pretty much zero roll authority below 60. If you do not follow the needed takeoff procedure (which they don't brief you on) the resulting flight looks very much like this crash: slow uncounteracted roll to one side or the other and a quick return to the ground.

[3WE]

I’m still not 100% sure what Gabriel was saying, but I think it’s (paraphrased):

Even though you guys don’t see an obvious stall/sudden wing drop, it’s still POSSIBLE that the plane had degraded roll control due to slow speed and/or the beginnings of a stall.

Just not sure how the totally, intentionally crossed up MD-95 “violently” letting go is all that relevant to a slightly crossed up Caravan gradually banks to 45/whatever degrees without falling out of the sky. Maybe the same aerodynamic mechanisms, but a very different situation and response.

[ocelot]

By the magic of topic drift.