Good day,

Could someone help me get clarity re ENR 1.54 para 1.15. As I understand it for a night vfr approach, LSALT/MSA or MDA must be maintained until the circling area (all good there).

One can descend below if:
- At 5nm using VASI
- At 7 nm using VASI for a r/w equiped with an ILS
- At 10 nm established on the ILS within less than half scale deflection

What would the point of 7 nm allowance be if there is already a greater allowance of 10nm? Supposedly if the AD's equipped with a ILS, to qualify you would have to have the ILS on and be using it and "aligned with r/w centreline established not below "on slope" - , thus 7 nm is OK. But 10 nm is also approved provided your established within 1/2 scale - in both cases both aircraft would be "established"?

For ease of reference this is on ENR page 1.5-13

tx any help would be appreciated

There are quite a few aerodromes that have VASI but no ILS. Most reginal aerodromes where jets land regularly have a VASI but not necessarily an ILS. Also some aircraft owners may not have installed an ILS in the aircraft but have a LOC capability. If you can see the VASI/PAPI lights during a visual approach at night, but do not have the ILS capability [or perhaps the aerodrome doesn't have an ILS], you can fly on the VASI from 5 nm out. If the VASI you are using is part of an ILS installation, you can fly visually on the VASI from 7 nm out. If you use the ILS you can fly visually on the ILS from 10 nm out.

I must admit that the whole thing is a bit ridiculous. What's the significant difference between 7 and 5 nm when you are approaching at 130 kt? About 90 seconds......

Bob

Tx Bob , your help is as ever much appreciated.