There have been various studies and reports into the true cost of low visibility procedures (LVPs) to airports, with each outlining the financial losses to both airports and airlines during periods of fog. The point at which an airport goes into LVPs is dependant on the RVR measured and calculated at a point in time. If the calculated RVR can be increased, through the UKCAA IRVR credits program (see attached) all stakeholders will benefit through:

1. Reduced CO2 emissions for aircraft holding unnecessarily

2. Improved airport safety - Pilots approaching in reduced visibility will be given improved IRVR readings

3. Reduction in length of time Airport’s would be operating under Low Visibility Procedures by reason of a less-pessimistic IRVR

4. Increased airport capacity because the onset of LVO would be delayed, and their cessation hastened
5. Chances of a successful approach increased and costs associated with diversion reduced
6. Reduce the number of occasions when a pilot will complain of glare

7. Airports with IRVR credits would be recognised by Stakeholders for their efforts in raising standards and gain an operational advantage


A study published in April 2019 by Atmosphere Journal investigated the “Loss to [the] Aviation Economy due to winter fog in New Delhi during the winter[s] of 2011-2016”. It was concluded that “The total number of flights cancelled, diverted, and delayed during this period was 351, 398, and 567, respectively. This led to a total economic cost of approximately 3.9 million USD (248 million Indian rupees) due to flights affected by heavy fog spells at IGI Airport over five years.

In summary, IRVR credits and the ability for airports to benefit from proper and regular AGL maintenance is a good thing. However, this does still need investment in both time and equipment. Remember, if an airports average AGL intensity is below that programmed into its IRVR equipment, the declared Runway Visual Range will be overstated and safety will be compromised.

For further information into RVR and IRVR credits, or how MALMS can help your airport, please contact