Performance and Limitations

Question 1

Density Altitude

Answer 1

• pressure altitude corrected for non standard temperature
• less dense air causes decreased lift (thinner air exerts less force on wings), decreased power (less air molecules in the engine, decreased thrust (propellers are less efficient)
• hot day = high DA/worse performance, aircraft “feels” like flying at higher altitude, high elevation, high temperature, low atmospheric pressure, high humidity
• cold day - low DA/better performance, aircraft “feels” like flying at lower altitude, low elevation, low temperature, high atmospheric pressure, low humidity

Question 2

Effect of pressure on density

Answer 2

• density is directly proportional to pressure

- if pressure is doubled = density is doubled

Question 3

Effect of temperature on density

Answer 3

• temperature is inversely proportional to pressure

- decreasing temperature increased pressure

Question 4

Effect of humidity on density

Answer 4

• humidity = amount of water vapor in the air
• water vapor is lighter than air = moist air is lighter than dry air = moist air is less dense than dry air
• high humidity = decreased performance

Question 5

Effects of exceeding airplane limitations

Answer 5

• structural damage or failure
• longer ground roll on takeoff and landing
• decreased performance