How would an airspeed indicator be marked to show the best rate of climb speed (one engine inoperative)?

The best rate of climb speed with one engine inoperative is typically marked on the airspeed indicator with a blue radial line. This designation indicates the speed that offers the best altitude gain over time under specific conditions, essential for single-engine operations. The blue radial line serves as a visual cue for pilots, indicating that this speed provides optimal performance when dealing with the loss of an engine, allowing them to maintain control and maximize their climbing capabilities in such scenarios.

In aviation, different colors on the airspeed indicator represent various operating limits or performance parameters, such as the red radial line which usually signifies the never exceed speed, the green arc indicating normal operating range, and the yellow arc showing caution speed limitations. Each color plays a vital role in conveying critical information to the pilot, helping them make informed decisions in flight.