Hi everyone,
Something I've been a tad confused about for a while is the reference from AIP 1.5 - 15 and the requirements for a visual approach at night.
There are two paragraphs which state the following:
- within 5NM (7NM for a runway equipped with an ILS/GLS) of the aerodrome, aligned with the runway centreline and established not below
"on slope" on the T-VASIS or PAPI; or
- within 10NM (14NM for Runways 16L and 34L at Sydney) of the aerodrome, established not below the ILS/GLS glide path with less than full scale azimuth deflection.
My question is in relation to the 7NM requirement and the 10NM requirement. What is the difference? It seems that both aircraft will have the ILS tuned, so why does one paragraph allow the visual approach to commence 10NM out and the other 7NM?
The fact is the "Electronic eyes" (ILS) can see further and better than human eyes, hence you can start approach from the greater distance.
Have a look at AND/OR/NOT keywords in the paragraphs.
Consider:
- Runways with ILS (e.g. Avalon, Essendon,..)
- Runways with VASI/PAPI lights only, but no ILS. (e.g. Ballarat, Latrobe...)
At 10nm you have to be not below the ILS glide path with less than full scale deflection. Lights are irrelevant. This can be done only in Avalon, Essendon...
At 7nm you have to be not below "on slope" on VASI/PAPI [u]AND[/u] runway equipped with ILS (Avalon, Essendon). You can't start approach in Ballarat, Latrobe..
At 5nm you have to be not below "on slope" on VASI/PAPI in Ballarat, Latrobe.
Hope above make sense.
