Question 18
Domain 2: FAA Part 107 WeatherWhat does "SM" indicate in a U.S. METAR report?
Correct answer: A
Explanation
In U.S. METAR reports, visibility is reported in "statute miles," abbreviated as "SM." This standard aviation weather format uses "SM" to show the visibility distance in miles rather than kilometers.
Why each option is right or wrong
A. Statute miles for visibility
Under FAA METAR conventions in 14 C.F.R. § 1.1 and the ICAO/FAA weather reporting format used in U.S. aviation weather observations, visibility is expressed in statute miles when reported in the U.S. system. The abbreviation "SM" is the standard unit marker appended to the visibility value, so a report like "10SM" means 10 statute miles of prevailing visibility, not nautical miles or kilometers.
B. Surface measurement
C. Sky measurement
D. Smoke meteorological