This famous pic which dates from some years ago
relates to this story
The impression I get is that he got this ice at FL140 or so and during the descent from there. Clearly he was unable to hold altitude at FL140 and I really don’t think a TB20 would hold altitude even at 5000ft with a deiced prop and at full power with this much ice, so he was lucky to reach an airport.
Super useful thread, great idea
20-25 Knots, 500ft climb rate, time VMC/below 0 OAT, 5 Minutes during climb, worst icing just before the tops reached (always a bad place/point)!
5-10 Knots, only 5 Minutes CU/TCU cruise/during climb.
5 Knots, after 60 Minutes cruise IMC below 0 OAT, Stratus
I only like this PIC
It’s possible that the ice was picked up in IMC between the buildups.
A good reason to keep out of IMC when there are any buildups around 
But in that case the extent of the IMC (at that level) was clearly limited in distance.
Interesting you had no turbulence in the tops of that TCU. You would expect it to be quite turbulent…
Pic 1 was picked up in 2 minutes in these cloud tops, at FL110 and -3C
Pic 2 was picked up in about 2 minutes in thick IMC, at FL150 and -5C.
No turbulence and no rain.
I think most people would call this “light icing” but you do need to have a viable Plan B which has to be either a descent into warm air or you know the IMC will end pretty soon. Icing is virtually assured (maybe not immediately) in thick IMC and -5C or so is the “best” place to get it.
So where does pic2 scale between light rime to severe icing?
> The first looks like a freezing rain shower, the second like a Stratus cloud, no rain. We can play guess the cloud the ice is come from ;-)
I reckon the first was in a particularly wet Cumulus cloud, agreed on the second… Peter?
…I wonder what the corresponding pictures are like for a PA28, C182, M20J, M20R and the Cirrus.
I would see 10-15 kts for the second picture in my M20J…..the difference is that my leading edge is much sharper than the relatively fat TB wing so I get that build up very rapidly…..not to mention what is happening on the even sharper tail plane…
I think the speed loss is not antennae etc as TedP surmizes, but rather mainly due to disruption of airflow causing reduced lift (at the normal AoA) thereby requiring an increased AoA to maintain altitude….and it’s associated aerodynamic drag
TB20 vs Mooney wings: Link
The first looks like a freezing rain shower, the second like a Stratus cloud, no rain. We can play guess the cloud the ice is come from ;-)
