AQT Aviation Weather & Meteorology 2 — Questions and Answers
Question 1: What is density altitude and how does it affect aircraft performance?
- Pressure altitude corrected for non-standard temperature; higher density altitude means thinner air and reduced aircraft performance (Correct answer)
- The altitude at which air density is zero
- The height of the densest cloud layer
- A measurement of aircraft weight
Correct answer: Pressure altitude corrected for non-standard temperature; higher density altitude means thinner air and reduced aircraft performance
Density altitude increases with higher temperature, higher elevation, and higher humidity. Thinner air reduces engine power output, propeller efficiency, and wing lift, requiring longer takeoff rolls and reducing climb rates.
Question 2: What are the conditions for VFR (Visual Flight Rules) flight?
- Minimum visibility and cloud clearance requirements that allow pilots to navigate by visual reference to the ground (Correct answer)
- Any weather conditions
- Only clear sky conditions with no clouds
- Flight above 18,000 feet only
Correct answer: Minimum visibility and cloud clearance requirements that allow pilots to navigate by visual reference to the ground
VFR requires specific minimums: generally 3 statute miles visibility and varying cloud clearance (500 below, 1000 above, 2000 horizontal in controlled airspace). Below these minimums, IFR rules apply.
Question 3: What is a microburst?
- A small-scale but intense downdraft that produces damaging winds near the surface, extremely dangerous during takeoff and landing (Correct answer)
- A small weather balloon
- A brief period of calm winds
- A type of lightning
Correct answer: A small-scale but intense downdraft that produces damaging winds near the surface, extremely dangerous during takeoff and landing
Microbursts are concentrated downdrafts less than 4 km across that produce divergent wind patterns at the surface. Aircraft entering a microburst first encounter a headwind (increased lift) then a tailwind (decreased lift), potentially causing crashes.
Question 4: What is the standard lapse rate of temperature with altitude?
- Approximately 2°C (3.5°F) per 1,000 feet (Correct answer)
- 10°C per 1,000 feet
- 0.5°C per 1,000 feet
- Temperature does not change with altitude
Correct answer: Approximately 2°C (3.5°F) per 1,000 feet
In the International Standard Atmosphere (ISA), temperature decreases approximately 2°C (3.5°F) per 1,000 feet of altitude gain up to the tropopause (~36,000 feet), which pilots use for performance planning.
Question 5: What causes fog and what types are most relevant to aviation?
- Fog forms when air temperature drops to the dewpoint; radiation fog, advection fog, and steam fog are most relevant to aviation operations (Correct answer)
- Fog is only caused by pollution
- Fog only forms over water
- Fog cannot form at airports
Correct answer: Fog forms when air temperature drops to the dewpoint; radiation fog, advection fog, and steam fog are most relevant to aviation operations
Radiation fog (nocturnal cooling), advection fog (warm air over cool surfaces), and steam fog (cold air over warm water) are the types most affecting airport operations, reducing visibility below safe minimums.
Question 6: How do pilots interpret winds aloft forecasts for flight planning?
- Winds aloft forecasts provide predicted wind direction, speed, and temperature at various altitudes, used to calculate groundspeed and optimal altitude (Correct answer)
- These forecasts only apply to surface winds
- Pilots do not use wind forecasts
- Wind data is only available during the flight
Correct answer: Winds aloft forecasts provide predicted wind direction, speed, and temperature at various altitudes, used to calculate groundspeed and optimal altitude
Winds aloft (FB) forecasts report predicted wind direction (true north), speed (knots), and temperature at multiple altitude levels, allowing pilots and dispatchers to calculate groundspeeds and select optimal routing and altitudes.
AQT Aviation Weather & Meteorology 2
What is density altitude and how does it affect aircraft performance?