Airspeed, Altitude, & Temperature

Question 1

Standard Temperature (ISA)

Answer 1

15°C (59°F) at sea level. ISA decreases 2°C (3.5°F) per 1,000 foot increase in altitude

Question 2

True Airpseed (TAS)

Answer 2

Add 2% to indicated airspeed (IAS) for every 1,000 foot increase in altitude

Question 3

Density Altitude

Answer 3

For every variation of ±15°F or ±8°C from standard temperature at a given pressure altitude, density altitude increases/decreases 1,000 feet

Question 4

Air Density/Humidity

Answer 4

For every 20°F temperature increase air density decreases 2-3% (moisture holding capacity doubles)

Question 5

Relative Humidity

Answer 5

Dew point/Temperature = Percentage [Example: (11°C/20°C) = 55%]

Question 6

Density Altitude

Answer 6

Increases or decreases 120 feet for each 1 degree Celsius that the temperature varies from standard temperature

Outside temperature minus standard temperature multiplied by 120 plus pressure altitude

Example: (OAT-ISA) x 120 + PA = DA

Question 7

Calculating standard temperature at altitude

Answer 7

Example of 12,000 feet: (12 x 2) - 15 = 9. Convert to a negative. -9°C at 12,000 feet

Question 8

Celsius to Fahrenheit

Answer 8

15°C, for example: (15 x 2) + 30 = 60°F (59°F)

Question 9

Fahrenheit to Celsius

Answer 9

59°F, for example: (59 – 30) ÷ 2 = 14.5°C (15°C)

Question 10

Maneuvering Speed (V_a)

Answer 10

Reduce V_a by one-half the percentage of weight reduction.

Example: V_a at 3,000 lbs = 100kts.; 2,400 lbs = 20% reduction on weight. Reduce V_a by 10 kts

Question 11

Maneuvering Speed Formula

Answer 11

V_a2 = V_a√(W₂ ÷ W₁); whereas V_a2 is calculated maneuvering speed, V_a is maneuvering speed at gross weight, W₂ is reduced weight, and W₁ is gross weight

Question 12

Stall speed

Answer 12

As weight doubles, stall speed increases by √2 or 60° turn, or 1.414