What is rvr equipment

Normally two ALSs are installed in central locations relative to the airfield environment. Next, the runway light intensity monitor, or RLIM, establishes the proper intensity of a high-intensity runway lighting system in varying visibilities, based on data from the ALS. Eventually, data from all the sensor elements finds its way to the data processing unit, the main RVR computer, where the final calculations are performed to create the RVR readout placed in front of a tower or radar-room controller.

For one, the pilots will have an idea of the actual conditions on the runway before the approach. RVR also allows for lower landing minimums in some situations. Cat 2 and Cat 3 ILS approaches require runway visual range.

RVR may be reported in either feet or meters, depending on the location in the world. In the United States, it will be in feet. METARs are routine weather reports published for airports all over the world. Pilots refer to these coded weather observations when planning flights and even when in the air approaching their destination. Translation: North Bay Airport, 15th of the month at Zulu time.

Automatic report. On most runways equipped with RVR, there are three sensors: a touchdown sensor, a mid-point sensor, and a rollout sensor. While it's good to know about the sensors, it's even better to be able to actually read RVR. So let's jump into that.

RVR is only reported at airports that have RVR sensing equipment, when the visibility is 1 statue mile or less, or when RVR for an instrument runway is 6, feet or less.

Screenshots taken from our Aviation Weather Products online course. In this example, "" indicates the RVR for runway 18R is feet. The increments that RVR visibility is described in also changes as the visibility gets lower.

The lower the visibility, the smaller the increments that RVR is reported:. If visibility is less than the lowest reportable RVR value, an "M" is placed in front of it. And if the visibility is greater than the highest reportable value, a "P" is placed in front of it. And when RVR varies by more than one reportable value over a minute period, the lowest and highest values are paired with a "V" between them. In this example, "V", indicates the RVR for runway 18R is varying between feet and feet.

After all, the pilot is not a certified observer on the ground. The pilot is in an aircraft looking forward. Another indication is the way the sky condition is described. Manual reporting stations staffed by weather observers report SKC for sky condition clear.

Automated weather stations report CLR to indicate no clouds below 12, feet. If the word AUTO is absent it means that the readings obtained by the visibility sensing equipment is being augmented by a certified weather observer. A certified weather observer is a person who is physically present at the airport and has been trained in meteorology and passed a certifying exam.

As someone who has worked as a certified weather observer, I can personally say that the exam was not easy! I would then compare what the computer was indicating for visibility compared to what I was seeing with my own eyes.

I had the advantage of being able to look at multiple areas of the airport and had predetermined landmarks aiding me in identifying how far I could see. I would determine the greatest horizontal visibility equaled or exceeded throughout at least half the horizon circle not necessarily continuously and that would be the prevailing visibility.

If the transmissometer which senses visibility was wrong I would override it and publish the actual prevailing visibility. Although augmented weather observations are better than automated ones they are still not good enough for operations in extremely poor weather conditions.

RVR is the best way a pilot can know exactly what the visibility is going to be directly over the runway. It is used primarily for operations in very low visibility so you will often see RVR equipment at large airports with lots of airline or jet traffic.

The transmissometer projector and receiver are mounted on towers feet apart. A known intensity of light is emitted from the projector and measured by the receiver.