FAA Commercial Pilot Airplane (CAX)WeatherMedium
A pilot is planning a flight through an area where a SIGMET is issued for 'OCNL SEV TURB BLW 080 FL200'. What does this SIGMET indicate?
- AOccasional severe turbulence below 8,000 feet MSL, extending up to Flight Level 200.
- BOccasional severe turbulence between 8,000 feet MSL and Flight Level 200.
- COccasional severe turbulence with a base of 8,000 feet AGL and top at 20,000 feet MSL.
- DOccasional severe turbulence occurring only at Flight Level 80 and Flight Level 200.
Show answer & explanationAnswer & explanation
Correct answer: B. Occasional severe turbulence between 8,000 feet MSL and Flight Level 200.
In a SIGMET, 'OCNL' means occasional, 'SEV TURB' means severe turbulence. 'BLW 080' is read as below FL080 (8,000 ft MSL), and 'FL200' is Flight Level 200 (20,000 ft MSL). The notation 'BLW 080 FL200' indicates turbulence between these two altitudes, not below 8,000 feet and then up to FL200.
Why the other options are wrong
- A. Incorrect interpretation of 'BLW 080 FL200'. It's an altitude range, not 'below' then 'up to'.
- C. Incorrectly interprets '080' as AGL and the overall altitude range.
- D. Incorrectly assumes turbulence only at specific flight levels, not throughout the range.
SIGMET Altitude Range
SIGMETs specify altitude ranges for hazardous weather using 'BLW' (below), 'ABV' (above), or a range between two flight levels or MSL altitudes.
- FL refers to Flight Level (hundreds of feet MSL, e.g., FL200 = 20,000 ft MSL).
- MSL altitudes are usually given as three digits (e.g., 080 = 8,000 ft MSL).
- A range like 'BLW 080 FL200' indicates between 8,000 ft MSL and 20,000 ft MSL.
Memory trick: SIGMET's sky levels, a pilot's high-low truth.