If the airspeed indicator shows 80 mph at 5000 feet, what is the actual speed?

To understand why the correct answer is 88 mph, it's essential to delve into the relationship between indicated airspeed, true airspeed, and altitude. The airspeed indicator displays what is known as indicated airspeed (IAS), which is the speed of the aircraft relative to the surrounding air. However, indicated airspeed does not account for changes in air density and temperature with altitude.

At higher altitudes, such as 5000 feet, the density of air decreases. As a result, true airspeed (TAS) increases relative to indicated airspeed due to these environmental factors. Generally, for small corrections, one can estimate that true airspeed increases by a certain percentage based on altitude.

In this scenario, if the indicated airspeed is 80 mph at 5000 feet, the true airspeed can be calculated considering the effects of altitude on air density. Through relevant equations or conversion charts, at an altitude of 5000 feet, the true airspeed is typically higher than the indicated airspeed, and for this specific example, it rounds to approximately 88 mph.

In summary, understanding the differences between indicated airspeed and true airspeed is crucial in aviation contexts, particularly as altitude changes the density of air and thus affects the performance