Posted for JIMRHER@aol.com:


Thanks Larry, I appreciate your report.

I have had others who asked about the Alt Air door. I do have a manual control and a Light operated by a micro switch on the door and it was closed. I didn't notice that my inlet air temp was anything other than normal and the K&N filter is mounted so that only about 1/3 of it is exposed to the ram air. I don't think that I had any major blockage at the filter and my door was closed. Also, my engine temps came right back to normal after descending below the freezing level, where I pushed the power back up to hi cruise to see if everything was normal, and it was.

That is why I think is was cooling air INLET icing but don't really know.

My IAS was down to 140 KIAS at one point and I wonder what the STALL speed is with 1/8 or 1/4 in. of ICE and FL 250 +-? That would be a scary ride if it stalled up there.

I had other reports that it could have been Density Altitude, which I didn't look at, but over the desert this time of year it could have been higher than my altitude. I did have 2/4*F OAT at FL 230. Must look that up.

Make sure you have a HOT inlet on your turbine engine and make provisions for the Ice to not go into the turbine blades. The PT6 has an Ice door in the s bend of the air intake, does the Walter? Also you will be having a higher wing loading and higher altitudes but then you have the MACH heating to do most of your deicing.

Thanks and good luck,