“The RVR can be defined as the range over which the pilot of an aircraft on the centre line of a runway can see the runway surface markings or the lights delineating the runway or identifying its centre line.” The main purpose of RVR is to provide pilots, air traffic services (ATS) units information on runway visibility conditions during periods of low visibility, whether due to fog, the most frequent cause of low visibility in many places, or due to other causes such as rain, snow or sandstorms.

1. WELCOME

2. RVR TRANSMISSOMETER

3. INTRODUCTION
RVR
 “The visual range over which the pilot can see the runway surface
markings .”
 Assessment of visibility based on extinction coefficient of atmosphere,
runway light intensity etc.
 The purpose of RVR is to provide information to pilots , ATS.
TRANSMISSOMETER
 Instrument that automatically measures and reports RVR.
 It assess extinction coefficient and provides a reliable method of assessing
the atmospheric condition.
 Has a transmitter and a receiver.

4. NEED OF RVR CHECKING
IN AVIATION
 Majority of the accidents in the aviation sector are linked to
visibility haze.
 Visibility is restricted by the effect of light being disturbed by
atmospheric particles.
 Weather phenomena can reduce the visibility.
 Infinite visibility never occurs in the atmosphere.
 In aviation sector visibility haze is a main issue.

5. MOST COMMON WEATHER PHENOMENA
AND THEIR CHARACTERISTICS

6. CONVENTIONAL METHODS -
TRANSMISSOMETER
A)HUMAN OBSERVER TECHNIQUE
 An observer counts the number of runway lights or markers.
 This number is converted to runway visual range, making due
allowance for the differences in light intensity, background, etc.
 Human assessments are not accurate.
Disadvantages
 Accuracy and consistency are lower than instrumented RVR systems
 Change in weather conditions cannot be updated.
 Fluctuations of RVR cannot be indicated.
 Time consuming.

7. B) FORWARD-SCATTER METERS
 measures a small portion of light scattered out of a light beam.
 Used to estimate the extinction coefficient.
 Certain weather phenomena can reduce visibility by absorption .
 Deals with only scattering not absorption
 Appropriate calibration is needed with weather phenomena.
Disadvantages
 Measurement is not accurate.
 A forward-scatter meter is not self-calibrating.
 A reference “transmissometer” is needed for its calibration.
 Cost become twice.

8. FEATURES- TRANSMISSOMETER
 Gives specific RVR range.
 Quick response to changes in weather.
 Automated reports output every minute.
 Measurements valid both day and night in all weather conditions.
 Measures a few weather phenomena.
 Measures present weather(snow, freezing rain, rain, drizzle,fog ,sand)
 Highly reliable.

9. TRANSMISSOMETER

10. STRUCTURE- TRANSMISSOMETER

11. BLOCK DIAGRAM -
TRANSMISSOMETER

12. INSTRUMENTED RVR SYSTEMS

13. OPERATION –
INSTRUMENTED RVR SYSTEM

14. ADVANTAGES
 self-calibrating.
 Both absorption and scattering effects are correctly measured.
 The accuracy of the measurement does not depend upon the
weather phenomena.
DISADVANTAGES
 Covering the complete RVR range from 50 to 2 000 m with a single
instrument is technically difficult.
 Sensitive to errors caused by window contamination.
 Can not be recalibrated under low visibility conditions

15. FUTURE SCOPE
 Size can be reduced
 A single instrument which covers the entire range of RVR can be
implemented.

16. CONCLUSION
 Rate of accidents in aviation is reduced by this technology.
 Hope INDIA also will acquire this technology in all airports.

17. THANKS

18. Q&A