This one replaces the one that was previously posted and actually had some faulty and even dangerous advice. In fact, there has been suggestions made that Colgan pilot Marvin Renslow had been forced to view the previous stall video numerous times by his airline in training, hammered into the crews brains. Here’s Martha King on the subject:
“But during their airline training for winter operations the crew had been repeatedly required to watch a NASA-produced video titled “Tailplane Icing.” Their flight was in icing conditions at the time, and the video describes tailplane stalls, which, when they occur, are caused by ice accumulation on the horizontal stabilizer. The tailplane stall recovery procedure taught in the video directed pilots to pull back on the control column, reduce flap setting, and, for some aircraft, use only partial power—exactly what this crew did.”
The old advice was that in case of buffet, you could be suffering from a tail stall, which the correct way to recover from is to pull back, contrary to a wing stall recovery. That’s no longer that recommendation. Now the suggestion is that you can not suffer from tailplane icing unless you have full flaps. And any buffeting is an impending wing stall, not a tail stall. So forget everything the FAA previously taught you, and take this new one to heart! Anyway, interesting video to watch.
But perhaps even more interesting – maybe Marvin Renslow actually did exactly the right thing according to his training? dramatic drumroll, devil’s advocating, shit stirring mode
Very interesting – thank you Adam for posting it. Just watched it. Some key points:
Even on “FIKI” aircraft, you can have no stall warning despite having a heated switch. I assume this is because the switch simply doesn’t operate at the AoA at which the wing stalls with ice on it. I doubt this is widely known…
Ice encounters are unavoidable and every one is potentially different. They implicitly acknowledge that icing forecasts aren’t worth a whole lot.
Stall warning systems did not have to work in icing until new aircraft certified after year 2000, after which they also have to indicate the stall condition even with ice on the wing. I wonder how this was achieved? @pilot_dar may know more. This also means very few GA aircraft will have stall warners that are usable in icing. I doubt this is widely known, too…
The video is categoric that without flaps deployed there is no possibility of a tail stall. I think they say they found only full flaps can produce a tail stall on any aircraft they tested, and on some types only full flaps and max power would do it.
Nice video that end up with a very confusing decision making tree (probably let go stick and cut power is my best chance 
)
Peter wrote:
Even on “FIKI” aircraft, you can have no stall warning despite having a heated switch. I assume this is because the switch simply doesn’t operate at the AoA at which the wing stalls with ice on it. I doubt this is widely known…
Aerodynamic stall warning systems (e.g. P28 mechanic switch or C152 musical reed) will fail when a (smooth) wing surface changes its geometry a lot…
Not sure how other advanced stall systems work? do they measure AoA against a fixed critical value?
I guess talking about critical/non-critical AoA, stalled/non-stalled, laminar/non-laminar flow…for an (irregular) wing/elevator surface like those shown is like walking between Alps peaks and valleys and wondering if the earth is flat or sphere?
With visible wing contamination, and the tailplane being a slimmer/sharper airfoil/leading edge will accumulate proportionally more ice than the wing, most (?) turbine types will limit flaps and increase minimum speeds – the stick shaker/pusher will also activate at a (much) lower AofA when anti/de icing services are in use (eg inertial separator, propeller anti ice, inlet anti ice, boots). Landing distance required will typically increase by 60% or more.
The relatively recent AAIB for an Aurigny ATR may be of interest.
AdamFrisch wrote:
This one replaces the one that was previously posted and actually had some faulty and even dangerous advice.
Thanks for sharing.
