Cessna 185 in flight break up Feb 1997

[Squaretail]

Reading this just blows me away that two people survived this. The idea of the ski being whipped around by the prop like a blade is inconceivable.

https://www.tsb-bst.gc.ca/eng/rapports- ... q0032.html

[Slick Goodlin]

I never read it as the ski doing any cutting, it was more like the front half of the airplane pitched down faster than the back half could keep up with and it just split while the wings overloaded and clapped downward.

[Squaretail]

"Examination of the aircraft showed the right wing had red and black transfer marks from the right ski. The marks on the wing extended from the leading edge to the main spar, and there were also marks on the wing strut. Aft of the wing spar, there were tears caused by instantaneous overload. The wing attachment was still fastened to the carry-through structure. The carry-through structure failed in overload. The left wing also failed in overload, and it carried with it the rest of the carry-through structure. The fuselage separated aft of the seats. Red marks were found on the vertical stabilizer and left elevator."

The failure of the wing I'm seeing was initiated by the impact of the ski flung by the propeller, the torsion of the instant failure of the wing tore the fuselage at the rear follow through structure. So while engine is twisting off the front, wing is twisting on the side, a crazy amount of things to happen at once. Either way, two guys surviving it is nothing short of miraculous.

[cgzro]

While I cannot speak to the aerodynamics at play at full scale, and my Pitts was limited to wheels only thank god, I did fly many RC planes off frozen lakes with skis and any failure of the forward or rear cables (a weekly occurrence) had an effect similar to a full rudder deflection. Basically you'd be in a spin more or less instantly when it happened. I suppose its not impossible to have a similar effect at full scale but with more serious implications to loading of the aircraft structure.