WELCOME

RVR TRANSMISSOMETER

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.

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.

MOST COMMON WEATHER PHENOMENA

AND THEIR CHARACTERISTICS

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 dueallowance 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.

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.

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.

TRANSMISSOMETER

STRUCTURE- TRANSMISSOMETER

BLOCK DIAGRAM -

TRANSMISSOMETER

INSTRUMENTED RVR SYSTEMS

OPERATION –

INSTRUMENTED RVR SYSTEM

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

FUTURE SCOPE

Size can be reduced

A single instrument which covers the entire range of RVR can be

implemented.

CONCLUSION

Rate of accidents in aviation is reduced by this technology.

Hope INDIA also will acquire this technology in all airports.

THANKS

Q&A