AA,
Our local SOP dictates that all arrivals are switched to the tower prior to 3 miles from the runway.
If I have no other traffic that conflicts with the arrival, and the arrival will not violate another controllers or facilities airspace, and the arrival reports the airport in sight, I may clear the arrival for the approach (Visual Approach) as far as 30 miles or more out from the airport. Note, that this will only occur if it traffic is really slow.
If I feel confident that all the above can be accomplished, I may also switch the arrival over to the tower, normally I won't switch the arrival over to the tower until they are within 10 miles.
When I'm sequencing multiple arrivals, I do not switch the aircraft over to the tower until proper spacing / sequencing is established. Since we don't have authorization to use 2.5 miles on final, I'm restricted to 3 miles between, unless a large or heavy is involved (which adds more spacing for wake turb). VFR's I only need green between plus any required wake turb.
At KFWA we have the enjoyment of sequencing from C152's that struggle to do 60 kts on final to F16's that struggle to do only 210 kts on final. Yep, if you want to have fun, run a sequence of mixed airspeeds, or add in crossing runways for more entertainment.
Mike
NATCA FWA
GW-H,
If I don't feel confident that I can safely issue you a landing clearance or issue one to multiple aircraft, I don't. In our case approach sequences all arrivals (VFR and IFR), so as long as approach hasn't screwed the pooch, or I stuck someone in postion and hold when I shouldn't have, your early landing clearance is safe.
Safety is a two way street, and I'd rather have a pilot verify a clearance when they are in doubt than to assume and cause us both some grief.
Mike
NATCA FWA