FAA Commercial Pilot Airplane (CAX)WeatherMedium
A pilot is conducting a preflight briefing and notes a SIGMET for 'OCNL SEV TURB FCST FL200-FL350'. What does this indicate for the flight?
- AOccasional severe turbulence is forecast between 2,000 feet and 3,500 feet MSL.
- BOccasional severe turbulence is forecast between Flight Level 200 (20,000 feet) and Flight Level 350 (35,000 feet).
- COnly occasional turbulence, of severe intensity, will occur at 200 feet and 350 feet AGL.
- DForecast of occasional severe thunderstorms at 20,000 feet to 35,000 feet.
Show answer & explanationAnswer & explanation
Correct answer: B. Occasional severe turbulence is forecast between Flight Level 200 (20,000 feet) and Flight Level 350 (35,000 feet).
A SIGMET warns of significant weather phenomena. 'OCNL' means occasional, 'SEV TURB' means severe turbulence. 'FCST FL200-FL350' indicates the forecast altitude range is from Flight Level 200 (20,000 feet MSL) to Flight Level 350 (35,000 feet MSL).
Why the other options are wrong
- A. Incorrect. 'FL' indicates Flight Levels, which are thousands of feet, not hundreds, and MSL, not AGL.
- C. Incorrect. 'FL' does not refer to hundreds of feet AGL but thousands of feet MSL.
- D. Incorrect. 'TURB' means turbulence, not thunderstorms, and the altitude interpretation is incorrect for the lower end.
SIGMET Altitude Interpretation
In SIGMETs, altitudes prefixed with 'FL' (Flight Level) indicate thousands of feet Mean Sea Level (MSL), used primarily at or above 18,000 feet MSL.
- FLXXX means XXX00 feet MSL.
- Commonly used for high-altitude weather phenomena.
- Crucial for flight planning at higher altitudes.
- Below 18,000 feet MSL, altitudes are typically given as MSL or AGL.
Memory trick: Flight Levels Fly High, always in thousands MSL.