Just got this from a TB21+TKS owner, though his was retrofitted:
I don’t know of any heated stall warning option on the TB. I do know that in icing conditions the stall warner will ice up and be unusable.
Peter wrote:
Just got this from a TB21+TKS owner, though his was retrofitted:I don’t know of any heated stall warning option on the TB. I do know that in icing conditions the stall warner will ice up and be unusable.
So what about a heated AoA indicator as I first suggested? Possibly no STC/337 required…
Would it work with an iced-up (aerodynamically modified) wing?
I don’t know.
The calibration procedure involves a flight with a clean plane.
However the heated AOA indicators are also not usable as they are. The main one, discussed here extensively e.g. here, will burn the paint off the wing if left on accidentally – unless modified. I just don’t think that sort of thing is acceptable… TSOd or not!
And putting a temperature or landing gear interlock on the AOA sensor is no different, in certification terms IMHO, from attaching a heating element to the little vane on the stall warner.
You could also give a look at the TB21 IPC ? I guess the stall warning parts numbers, for all the versions (factory TKS or not) should appear ?
Anyway, are those warning really useful ? :-p
TB21 is same
Peter wrote:
Would it work with an iced-up (aerodynamically modified) wing?I don’t know.
The same can be said of a stall warner….
Peter wrote:
You would have to find a TB20/21 owner with a factory installed TKS.
As I wrote, the TB20 with factory installed TKS I flew did not have a heated stall warning. Or at least there was no trace of it in the electric diagram.
All correct; the full-TKS STC from CAV for the TB series does not call for a heated stall warner.
In fact it creates an interesting stall warner serviceability scenario 
The Socata stall warner photos are here.
I wonder which parts are heated. Presumably the paddle must be heated, so it needs two wires running to it which need to be thin and flexible so they don’t interfere with the operation. The faceplate should be heated too.
Actually it is quite possible that looking at the panel design (see the top link above) there is TKS fluid getting onto the stall warner anyway. But it will also run into the hole and corrode the microswitch!
