How many anti-ice systems does the Boeing 737 have?

• A. Two
• B. One
• C. Three
• D. Four

Answer: (A)

Ice protection on the Boeing 737 relies on two independent anti-ice systems. One system heats the engine nacelles and inlets to prevent ice from forming on the engine intake area and around the nacelle surfaces. The other system heats the wing leading edges to keep that critical surface free of ice, maintaining proper airflow over the wing.

Having two separate systems provides redundancy and targets the two most important areas where ice would affect performance: the engine faces and the wing aerodynamics. If one system isn’t available, the other can still protect its respective surface, which is why two is the correct count.