Page 22 - July24

ASK THE EXPERT
Takeoff OAT Restrictions
by Tom Clements
I’ve been asked about engine ice vane usage on the ground. Specifically, a concern was expressed about a temperature restriction stated in the Pilot’s Operating Handbook (POH) for the model 200-series. Is a limit being violated at times when ice vanes are being used?
I’ve had a similar concern for the 300-series. I plan to review and discuss these questions and more in this article.
Realize that all King Airs have an OAT limit above which they are not allowed to operate. In almost all cases this is expressed as ISA + 37°C. “Golly, 37°C is only 98.6°F, so there’ll be many times that we cannot fly!”
20 • KING AIR MAGAZINE
many folks think. Wrong! The 37°C temperature is not the same as “ISA + 37°C.” ISA stands for “International Standard Atmosphere,” the engineering-accepted model of the average worldwide atmosphere. This is the one with a Sea Level temperature of 15°C or 59°F and a lapse rate of 2°C for every 1,000 feet up to the stratosphere that starts at FL350. ISA + 37°C is a shorthand way
JULY 2024