Hey Bob et al,

I've been going through your IREX book (2011 edition) in order to study for a job interview. In it you are explaining when you can descend below the LSALT.

1. Radar Vector
2. DGA
3. IAP
4. Climbing after departure
5. Visual Approach

You then go on to talk about operating in VMC below the LSALT, this happens a lot up north in the TS and Darwin.

In this process you ask "what is the point of a 30nm limit?" [visual approach criteria]

A visual approach is fundamentally similar to VMC except one thing, that's it is not.
A visual approach by day requires you to remain in sight of ground or water, with an inflight visibility no less than 5000, and operate clear of cloud, and whilst maintaining the above conditions do not descend below the minimum altitudes set out in CAR 157.

Vmc is set out in ATC 502 para 3
Read it I can't remember the distance from cloud bits...

So doing a Visual Aproach (a legitimate IFR procedure) gives you more flexibility, you can shoot a hole in the cloud without having to worry how far you are from cloud etc. imagine you're flying a turboprop and descending on a 3:1 profile so at 30nm you're at FL150 you need 1000' vertical and 1500m horizontal separation from cloud to remain in VMC... when someone can tell how far that is let me know. (My debrief item on my cpl test)

Whereas I'm flying to a destination, the departure aerodrome is cavok, I get to a cruising altitude and can see my destination 50 mm away, the highest terrain enroute is 200' so RLSALT is 1500'. I've got ovc stratus at 1000', but I can descend in VMC and can still fly to the destination under VMC under the IFR at say a minimum 700' and remain clear of cloud and in sight of ground or water, with 5km visibility. Whereas doing visual approach won't get you to your destination.

I realise that this is super sketchy, but it's legal...

AIP ENR 1.5 -15 1.14
BY DAY
within 30 miles
clear of cloud
in sight of the ground
5000 metres viz
and not below 500 feet until established on centre line

VISUAL reference?
And usually is specified for a procedure like
VISUAL DESCENT (Clear of cloud ground and obstacles) weather permitting.
With minimum visibility.
maintaining terrain clearance Visually
Read CHPTR 16 CIR rating Book
Its not necessarily in VMC.
After an approach you can by day circle within limits at 300/400 agl until on centre line, that is not VMC.
and you can fly below LSALT cross country maintaining terrain visually.. do it all the time.
Flight viz applies of course.

By night whole new ball game.
not below LSALT
within 5 miles etc etc