Which action is recommended to optimize engine cooling during a climb?

• A. Reduce rate of climb and increase airspeed
• B. Increase rate of climb and increase airspeed
• C. Maintain climb rate and reduce airspeed
• D. Lower engine power to idle

Answer: (A)

Engine cooling during climb is driven by how much air flows over the engine. The more air moving past the cylinders, the more heat is carried away. Increasing the airplane’s airspeed increases ram air cooling, while climbing at a steeper angle usually reduces airspeed and thus cooling effectiveness. So, to optimize cooling while climbing, you want to fly faster through the air, which is achieved by reducing the rate of climb. This lets you maintain or increase airspeed and improves cooling.

The idea behind this option is that lowering the rate of climb raises the airspeed for a given power setting, enhancing cooling without sacrificing altitude excessively. Increasing the rate of climb tends to reduce airspeed and worsen cooling. Maintaining the same climb rate while reducing airspeed also reduces cooling. Dropping engine power to idle lowers heat generation but massively cuts the cooling airflow and isn’t a reliable way to optimize cooling during a climb.