CTO Weather Observation & Reporting 3 — Questions and Answers
Question 1: An ATIS broadcast indicates 'Runway Visual Range 2400 feet.' What is the primary source of this RVR value?
- Transmissometer or forward scatter sensor at runway touch-down zone (Correct answer)
- Tower controller visual estimate
- Pilot reports from landing aircraft
- ASOS visibility sensor on the field
Correct answer: Transmissometer or forward scatter sensor at runway touch-down zone
RVR is measured by transmissometers or forward scatter sensors positioned at the runway touchdown zone, mid-field, and rollout areas.
Question 2: When are controllers required to issue a Low-Level Wind Shear Alert System (LLWAS) alert to pilots?
- Whenever the system detects a wind shear alert of 15 knots or greater (Correct answer)
- Only when wind shear is within 500 feet of the runway
- When reported by at least two pilots
- When the alert threshold exceeds 25 knots
Correct answer: Whenever the system detects a wind shear alert of 15 knots or greater
FAA orders require controllers to alert pilots to LLWAS wind shear alerts of 15 knots or greater microburst alerts.
Question 3: What information does the 'PRESRR' remark in a METAR convey?
- Pressure rising rapidly (Correct answer)
- Pressure remains relatively steady
- Pressure reading revised
- Pressure recorder reset
Correct answer: Pressure rising rapidly
PRESRR indicates the altimeter setting is rising rapidly, typically by 0.06 inches Hg or more in less than an hour.
Question 4: A SPECI is issued when visibility drops below which threshold while previously above it?
- 3 statute miles (Correct answer)
- 5 statute miles
- 1 statute mile
- 10 statute miles
Correct answer: 3 statute miles
A SPECI special observation is required when visibility falls below or recovers to 3 statute miles.
Question 5: What does the coded remark 'TS B25' in a METAR indicate?
- Thunderstorm began at 25 minutes past the hour (Correct answer)
- Thunderstorm base at 2,500 feet
- Turbulence severe beginning at 25,000 feet
- Thunderstorm bearing 025 degrees
Correct answer: Thunderstorm began at 25 minutes past the hour
In METAR remarks, 'TS B' followed by minutes indicates when the thunderstorm began during the observation hour.
Question 6: A controller observes lightning in the distance but no precipitation is falling at the airport. What weather code is used in the METAR?
- VCTS (thunderstorm in vicinity) (Correct answer)
- TS (thunderstorm)
- DSNT TS (distant thunderstorm)
- LTG (lightning)
Correct answer: VCTS (thunderstorm in vicinity)
VCTS indicates a thunderstorm is occurring in the vicinity (5-10 miles) of the airport but not at the station.
Question 7: Which surface weather observation element is reported immediately after the date/time group in a METAR?
- AUTO or COR (modifier) (Correct answer)
- Station identifier
- Wind group
- Altimeter setting
Correct answer: AUTO or COR (modifier)
After the date/time group, a METAR shows AUTO for automated observations or COR for corrected reports before the wind group.
CTO Weather Observation & Reporting 3
An ATIS broadcast indicates 'Runway Visual Range 2400 feet.' What is the primary source of this RVR value?