ShyTorque
That reminds me of the night (just before the end of official night) I came out of Castle Air in Cornwall. CAVOK, stars twinkling in the dark sky.
Aircraft taken out of chilly but not freezing hangar into cold air outside.
Lights on around the site give very good visual cues for departure.
Helipad departure to the North and just at the point of rotation (going upwards and backwards at 0 IAS) all the windows froze over on the outside. It wasn't gradual it was instant, can see one moment, can't the next.
Followed the helipad procedure (although only 5 deg nose change down as engine failure was the last of my interests at that moment) on instruments rather than reverse into the hill or down onto the hangar I now can't see.
I suppose with the attitude hold / force trim etc in the 109 I could have taken the door open approach but it came as such a shock I really didn't want to risk letting of the controls, once I had the attitude set I let go of force trim and flew through the springs, it worked out, but I don't fancy it again.
The windows eventually cleared at 2000ft.
I was glad it was the E and not the AII that day.
I believe its related to the proximity of the stream to the helipad and me taking a condensation nucleus (the helicopter) through very cold, very damp, but very clean air.
GS