Question

The thinner air of higher altitudes causes the airspeed indicator to read "too low." An indicated airspeed of 80 mph at 5,000 feet is actually a true airspeed of approximately?

1) 72 mph
2) 88 mph
3) 96 mph
4) 104 mph
5) 112 mph

Answer 1

To find the true airspeed at higher altitudes, we need to use the altitude correction factor. For an indicated airspeed of 80 mph at 5,000 feet, the true airspeed is approximately 70 mph.

Step-by-step explanation:

The indicated airspeed at higher altitudes is lower than the true airspeed due to the thinner air. To find the true airspeed, we need to correct for the decrease in air density. One way to do this is by using the altitude correction factor, which accounts for the decrease in air density with altitude:

1. First, calculate the altitude correction factor: altitude correction factor = 1 / (1 + (altitude in feet / 8800)
2. Then, multiply the indicated airspeed by the altitude correction factor to find the true airspeed: true airspeed = indicated airspeed * altitude correction factor

For this question, an indicated airspeed of 80 mph at 5,000 feet, the altitude correction factor would be 1 / (1 + (5000 / 8800)) = 0.879.

Therefore, the true airspeed would be 80 mph * 0.879 = 70.32 mph. Rounded to the nearest whole number, the true airspeed would be approximately 70 mph.