Cessna 172: I was taught to put carb heat on prior to any power reduction below the green arc.
The school I am instructing at has standardized pulling the carb heat AFTER reducing power.
This made me think about why I was taught carb heat first. My understanding is that turning carb heat on prior to power reduction is preferred because of the large pressure drop in the carb when closing the throttle. This pressure drop contributes to an increased likelihood of carb ice. Also, you want to put carb heat on when the exhaust manifold is nice and hot. If you use carb heat after a power reduction, the exhaust manifold may be cooler, or you might forget to use it at all.
Question: Am I wrong? Does it make a difference? Should I just accept the way the school has standardized this procedure or try to change it?
Thanks
The school I am instructing at has standardized pulling the carb heat AFTER reducing power.
This made me think about why I was taught carb heat first. My understanding is that turning carb heat on prior to power reduction is preferred because of the large pressure drop in the carb when closing the throttle. This pressure drop contributes to an increased likelihood of carb ice. Also, you want to put carb heat on when the exhaust manifold is nice and hot. If you use carb heat after a power reduction, the exhaust manifold may be cooler, or you might forget to use it at all.
Question: Am I wrong? Does it make a difference? Should I just accept the way the school has standardized this procedure or try to change it?
Thanks