The Gramet to me looks like you were flying through the tops of some towering cumuli. The tops of these clouds are full of super cooled dropplets which can ice up your aircraft very quickly so I am not sure whether you really encountered freezing rain.
The gramet pdf is only one page and this is the graphic:
It would be good to see the rest of the briefing pack. I can’t find the 1200 MSLP for 27/3/2018 and the 0000 MSLP which I did find shows this occluded front which is almost certain to contain plenty of convective wx and with very high tops to perhaps FL300 (you don’t need the gramet to work this out)
However I did find the IR images in the sat24 archive. Over Germany these show tops around FL150-200 and doesn’t relate well to the MSLP chart as far as that occluded front goes (the rest of it, e.g. over France, makes sense)
PetitCessnaVoyageur wrote:
Isn’t IO550 enough to cruise at FL160 ?
Sure I can get up there but I would have an IAS of 110 or so, and TAS of 135, MP of 15-16 inches.
Thats great if you have a strong tail wind not so, when looking at a 40Kt headwind. There is no performance left at that Altitude.
Those are rough numbers I gave since I dont have any books here with me.
placido wrote:
The Gramet to me looks like you were flying through the tops of some towering cumuli. The tops of these clouds are full of super cooled dropplets which can ice up your aircraft very quickly so I am not sure whether you really encountered freezing rain.
I was certainly not flying near the tops. However they did not look as if they were the classic towering CUs before I entered. I figure they went up from mid teens to FL200. There was some light to moderate chop when in the clouds so that kinda discounts strong severe updrafts. Unless it was above my altitude.
Regarding rain. When you go through moderate to heavy rain, you can hear it even with Noise canceling headsets. It sounded like rain but it froze so I called it freezing slush rain.
It was unique never had anything similar in 37 yrs of flying IFR.
Did have one other instance of severe ice before I got the TKS which actually prompted me to dig into my pocket and spend 25K at the time to install one. Ive already related that here on the forum a while ago.
What was interesting, that once I got out of the IMC the radios developed a lot of static. My ADL 140 lost the signal to the Iridium Sat. It was only much later I switched it off and connected to an alternate power source. There it regained the signal. Then once that happened switched back to ships power and it remained connected. So not sure if rebooting it fixed the problem or switching to a different power source. Then back again.
All the symptoms (static in the vicinity, turbulence, and moderate-severe clear ice) point towards TCU / wannabe CB.
With additional layered cloud around, it might have been embedded in a bit of stratiform cloud, which could explain that they looked a bit different.
As far as the presence of SCLD is concerned – while they tend to live near the top of TCU during the build-up stage, once the updrafts calm down they drop down.
So the general rule of icing applies – it is very hard to forecast if and when you will get it, and how much…
But there was not that kind of Turbulence as Ive encountered in building CUs or near TCUs. Actually the Static started once out of the IMC conditions. It was also pretty constant in intensity. Might have been very fine snow considering it was 3F at FL120 Very hard to see that especially if between layers.
Even if it was dissipating TCU then there should have been noticeable down drafts which I did not encounter. Nothing seems to make sense. What I do know is it never seems to be by the book.
“Static” could just be ice on an antenna. Or ice on static wicks. Or just a lot of particles (water etc) being shed by the trailing edges.
I used to get really bad static due to having too much grease on the elevator bearings, so the electricity was arcing across them, on the way to the static wicks on the elevator :) Now they are bypassed with copper braid, two pieces!
