CPL Aviation Meteorology 3 — Questions and Answers
Question 1: Which METAR sky condition code indicates a ceiling that makes VFR flight illegal under FAA regulations in controlled airspace?
- SCT025
- BKN025 (Correct answer)
- FEW025
- OVC045
Correct answer: BKN025
BKN025 (broken ceiling at 2,500 feet) creates a ceiling below the 3,000-foot AGL threshold, making VFR flight illegal in Class B, C, D, and E controlled airspace without a clearance.
Question 2: Mountain wave turbulence is MOST severe at which location relative to the mountain ridge?
- Directly over the windward slope
- Immediately on the leeward side at ridge altitude (Correct answer)
- Well downstream of the ridge at lower altitudes
- Upstream of the ridge in the approaching airflow
Correct answer: Immediately on the leeward side at ridge altitude
The most severe turbulence in mountain waves typically occurs just downwind of the ridge at or slightly below ridge altitude, where rotor and wave action are most intense.
Question 3: What does the term 'LLWS' represent in aviation weather, and what is the standard threshold altitude for this phenomenon?
- Low-Level Wind Shear below 2,000 feet AGL (Correct answer)
- Low-Level Weather System below 5,000 feet MSL
- Low-Latitude Wind Shift below 3,000 feet MSL
- Localized Low-pressure Weather System below 1,000 feet AGL
Correct answer: Low-Level Wind Shear below 2,000 feet AGL
Low-Level Wind Shear (LLWS) refers to sudden changes in wind speed or direction at or below 2,000 feet AGL, posing significant hazards during approach and departure.
Question 4: A pilot notices that the altimeter setting has changed from 29.92 to 30.12 inches Hg during cruise flight at constant altitude. If the altimeter is not reset, the aircraft is actually flying at what altitude relative to indicated?
- 200 feet higher than indicated
- 200 feet lower than indicated (Correct answer)
- No change — only sea level pressure reference changes
- 2,000 feet higher than indicated
Correct answer: 200 feet lower than indicated
Each 0.01-inch change in altimeter setting equals approximately 10 feet; an increase of 0.20 inches means actual altitude is 200 feet lower than indicated if not reset.
Question 5: Which condition is associated with the formation of clear ice on an aircraft?
- Flight through cirrus clouds above -40°C
- Flight through large supercooled water droplets at temperatures between 0°C and -10°C (Correct answer)
- Flight through light drizzle at temperatures below -20°C
- Flight in dry snow at temperatures between -5°C and -15°C
Correct answer: Flight through large supercooled water droplets at temperatures between 0°C and -10°C
Clear ice forms when large supercooled water droplets spread over a surface before freezing, typically in temperatures between 0°C and -10°C, creating a smooth, dense, and heavy ice accretion.
Question 6: A Terminal Aerodrome Forecast (TAF) is valid for what standard period, and how frequently is it updated at major airports?
- 12 hours, updated every 6 hours
- 24 hours, updated every 6 hours (Correct answer)
- 6 hours, updated every 3 hours
- 48 hours, updated every 12 hours
Correct answer: 24 hours, updated every 6 hours
Standard TAFs are issued for a 24-hour valid period and are updated every 6 hours at major airports; some airports may issue 30-hour TAFs.
Question 7: What is the primary hazard associated with 'Moist Adiabatic Lapse Rate' being less than the 'Dry Adiabatic Lapse Rate'?
- Clear air turbulence is more likely to develop
- A lifted saturated air parcel cools more slowly, remaining warmer than environment and promoting continued ascent and convective instability (Correct answer)
- Icing is more severe in saturated air masses
- Wind shear intensity increases above the cloud base
Correct answer: A lifted saturated air parcel cools more slowly, remaining warmer than environment and promoting continued ascent and convective instability
Because the moist adiabatic lapse rate (roughly 3°C/1,000 ft) is less than the dry rate (roughly 3°C/1,000 ft is wrong — MALR ~1.5°C/1,000 ft vs DALR ~3°C/1,000 ft), saturated rising air stays warmer than its surroundings, sustaining lift and convective development.
CPL Aviation Meteorology 3
Which METAR sky condition code indicates a ceiling that makes VFR flight illegal under FAA regulations in controlled airspace?