The operation requirement for ’slant visual range’ (SVR) has been discussed in subpara 2. Also an indication was given for the ideal situation re-availability of this kind of information.
The ICAO All Weather Operations Panel is of the opinion that a possible approach to such a complete solution may be to determine and to report to arriving aircraft the height at which a pilot will see and continue to see a minimum ground segment equivalent to 5 light bars of approach lights at 30 metres spacings.
The Panel realized, however, that for the time being it was not possible to build a SVR observing system capable of providing this kind of information.
The ICAO 8th Air Navigation Conference (Montreal, April 1974) recommended therefore that States be encouraged to develop a ’limited’ system sufficient to determine and to report to arriving aircraft the slant distance to the farthest high intensity runway edge light, or approach light, which a pilot will see from a height H above runway threshold elevation on the approach path.
(The value of H should depend on aerodrome conditions and types of aircraft operations).
Several countries adhere to ICAO’s request and are doing research work on SVR observing systems. Denmark, for instance, is investigating possibilities using backscatter techniques, other States focus attention on LASER.
1. Horizontal visibility aspects
2. Visual range
3. Observing techniques of RVR
4. Observing of RVR
5. Availability of RVR observations at ATS units
6. Reporting procedures of RVR reports
7. Accuracy of RVR reports
8. Slant visual range
9. The visual segment
10. Variation in visual segment
11. Flight visibility and vision at high altitudes