Automatic measurement systems for Runway Visual Range
| industrial collaborators: | TMS Photometrics |
| academic collaborators: | ESGI59 |
| initiated : | 2007/08/30 |
| last updated: | 2010/05/25 |
Study group report 2007: Runway Visual Range (TMS Photometrics)
This is the final report on the problem of evaluating automatic measurement systems for Runway Visual Range, brought to ESGI59 by TMS Photometrics. Click on the link at the bottom to download the full report as a pdf document.
Report author
Tim Gardener (Industrial Mathematics KTN)
Executive summary
Runway Visual Range (RVR) is defined to be the horizontal distance a pilot can see on the runway.
Figure 1: Runway Visual Range.
International Regulations require that an airport should calculate the local RVR in order to determine whether it is safe to land and how many aircraft can be landed safely per hour. These regulations are authorised by the International Civil Aviation Organization(ICAO). There are two ways that RVR can be calculated:
- Either a human observer on the runway makes a judgement by counting the number of lights visible down the runway from a fixed observation point; or
- one uses Allard’'s Law together with measurements of absorption and background illumination and values for the intensity of the lamps on the runway.
At Birmingham International Airport (BHX) the second method is used. Absorption and background illumination are both easily measured, but the intensity of lamps can vary considerably along the runway. The intensity of individual lights can be measured, but Birmingham (along with most other airports) chooses to use standardised values conservatively estimated. Conservative estimates of light intensity lead to lower than necessary estimates of RVR. BHX uses RVR to determine four operational states; these states dictate how many aircraft are permitted to land per hour.
The principal question amounts to this: What is the gain in terms of airport throughput of using measured light intensities as an input to Allard'’s law compared to the conservative estimated values?
To answer this, the Study Group first investigated the e¤ect of using more less conservative light intensity values in Allard’'s Law on RVR. If less conservative values could be seen to give a significant benefit in terms of airport throughput then it would be economically sensible for the airport to invest in an accurate measurement system for light intensity values.
Then the Study Group analysed the data provided for BHX to determine how a revised value for RVR may be significant in the scheduling of aircraft landings. Data on the minute by minute variation of background illumination and absorption over the course of an entire year was available for analysis. The Study team developed an efficient algorithm to determine the state of the airport in hypothetical light intensity conditions.
Click on the link below to view the full report.
