Federal Meteorological Handbook No. 1

APPENDIX C

SENSOR STANDARDS


C.1 Runway Visual Range Standards. Table C-1 lists the required accuracy in feet for runway visual range sensors.

Table C-1. Accuracy for Runway Visual Range
Runway Visual Range in FeetAccuracy
<1,300 feet±30 feet
1,300 through 2,600 feet±80 feet
>2,600 feet±10 %

C.2 Visibility Sensor Standards. Table C-2 lists the accuracy for automated visibility sensors.

Table C-2. Accuracy of Automated Visibility Sensors
Visibility from
Standard
Visibility Sensor		 Percentage of Data Within or Exceeding Given Range
At least 80% Within No more than 18%
Exceed		 No more than 2%
Exceed
0 through 1¼ ±¼ ±½ ±1
1½ through
1¾		 +¼, -½ +½, -¾ ±1
2 through 2½ ±½ ±1 ±1
3 +½, -1 ±1 ±1
4 through 10 ±1 RV¹ ±2 RV¹ ±2 RV¹ 
RV = Reportable value, all other values in miles.

C.3 Wind Sensor Standards. Table C-3 lists the units of measure, the range, the accuracy, and the resolution for pressure parameters.

Table C-3. Units of Measure, Range, Accuracy and Resolution of Wind Parameters
ParameterUnits of
Measure		 RangeAccuracyResolution
Direction Degrees 1° to
360°		 ±5° when speed is >=5
knots		 10°
Speed Knots 2 to 90
knots		 ±1 knot up to 10 knots
±10% above 10 knots		 1 knot

C.4 Wind Sensor Standards. Table C-4 lists the range and accuracy for sky conditions.

Table C-4. Range and Accuracy of Sky Condition Parameters
ParameterRange Accuracy
Amounts Heights
Sky Condition 0 - 12,000 ft. (minimum) ±1 Reportable Value ±3 Reportable Values

C.5 Temperature and Dew Point Parameter Standards. Table C-5 lists the range, accuracy, and resolution in degrees Celsius for temperature and dew point parameters.

Table C-5. Temperature and Dew Point Sensor Accuracy and Resolution (C°)
ParameterRange AccuracyResolution
Temperature -62 to -50
-50 to +50
+50 to +54		 ±1.1
±0.6
±1.1		 0.1
0.1
0.1
Dew point -34 to -24
-24 to -01
-01 to +30		 ±2.2
±1.7
±1.1		 0.1
0.1
0.1
C.6 Pressure Parameter Standards. Table C-6 lists the units of measure, the range, the accuracy, and resolution for pressure parameters.

Table C-6. Units of Measure, Range, Accuracy and Resolution of Pressure Parameters
ParameterUnits of
Measure		 RangeAccuracyResolution
Station PressureInches of
Mercury		 4±0.02 0.0005 inch
Altimeter SettingInches of
Mercury		 4±0.02 0.001 inch
Sea-Level PressureHectopascals 136±0.68 0.1 hectopascal