This is from 8 years ago
It was a post maintenance flight test, near Norwich EGSH. They cleared me to FL200 and then London Control gave them a bollocking so I had to go down to FL195. I saw +300fpm so the plane would have done ~FL230.
I thought we had a thread on this but can’t find it.
Funnily this was also in cold winter near Norwich (turbo Mooney)
We flew without O2 between FL200-FL80, each one of us having a go each time
London ATC were very accommodating in/out of airspace in that spot
I picked up a C 172 at -41C surface temperature in central Quebec many years ago, and climbed to 6500 feet to fly it home.
I picked up a C 172 at -41C surface temperature in central Quebec many years ago, and climbed to 6500 feet to fly it home.
How do you avoid going above 3000rpm on takeoff? 
The answer is we do not know:
But as the manual said we better get into warmer air we did descent and at -57C it started to display again:
But the question is what and where you measure. On the PA46 we usually have 9 to 10C heating through speed so TAT is higher than OAT. The Lear 75 must have much more, so it actually does not “feel” the -73C
It amazes me how many people don’t have an OAT gauge 
Aerodynamic heating reaches 15C at 350KTAS but in piston GA you would struggle to reach 2C.
Peter wrote:
in piston GA you would struggle to reach 2C.
You would in your TB20. 140 KTAS gives 2°C.
