When are HISL required?
 

Just a quick question,
Does a red rotation beacon on the tail or a white nav light replace the need for HISL on the wing tips when ever they're required?

Yes, sort of. You must have an anti-collision beacon during the day and night. Such a beacon can be either a red or white flashing light and is usually switched on before engine start.

The steady white nav light is requirement at night along with the green and red wing-tip nav lights.

Drifter,
I don't think so. Nothing is required for daytime and red or white rotating or flashing lights are optional at any time. Red, green and white lights in the appropriate places are required during"night" operations.
Someone better qualified please correct me if I'm wrong.

Mike W

If you've got them by the way, use them but do not operate white High Intensity lamps until you are on the runway and about to take off.

M

Ah yes. But if the aircraft is fitted with such a light it must be used though, even by day.

None of the above! Red rotating beacons (anti-collision lights) are ONLY madatory on aircraft over 5700 Kgs (I recall) and must be used at all times on such aircraft!
UV

Rule 9 doesn't specify a weight. Is there a caveat to counter it?

Note to self: Too much prooning of late. Must actually do some flying!

"Red rotating beacons (anti-collision lights) are ONLY madatory on aircraft over 5700 Kgs (I recall) and must be used at all times on such aircraft!"

Or on a helicopter..

In the interests of self preservation I would leave all the lights on all the time when airbourne (except in IMC at night where strobes can be distracting). We fly with the landing lights on all the time as well because it reduces the risk of a bird / Tornado strike.