Thanks for your reply,
So if I understand your post, it is perfectly "legal" for a VFR tower to issue control instructions to an IFR aircraft other than "cleared for take-off?"
Just to be in the know, there really isn't a "VFR" tower. When you are referring to a field that is controlled, the meteorological conditions come into play. VMC (visual meteorological conditions) are when you can use VFR and IFR operations at that field; IMC (instrument meteorological conditions) are when you can
only use IFR operations at that field.
With that, back to your question: Yes, it is perfectly legal for a tower in VMC to issue instructions to an aircraft operating under IFR other than "cleared for takeoff". Prime examples: Make left traffic, Make right traffic, enter left base, enter right base, enter left/right downwind, circle to land.
The 7110.65 specifically states that an aircraft conducting a visual approach has no missed approach and will be treated like a regular "go-around". However, a circling maneuver (from a surveillance approach) is a radar approach and IFR separation is provided until the aircraft lands. Furthermore, the aircraft conducting the circling approach has either a published missed approach (instrument approach) or ATC issued missed approach (radar approach).
a. When an aircraft is conducting a surveillance approach and is instructed to proceed visually (in accordance with directives) approach guidance is discontinued not radar service. Radar service is terminated when the aircraft completes the radar approach.
b. Radar service is AUTOMATICALLY terminated when arriving VFR aircraft receiving radar services request or is instructed to contact tower or change to advisory frequency.
QUESTION: When the aircraft commences circling and is instructed to contact tower, is he considered a visual approach?
No. If the pilot was cleared for an IFR approach (ILS, MLS, RNAV/GPS, VOR, NDB, etc.) with "circle to land", the pilot is still adhering to the IFR procedure the pilot was cleared for by the approach controller. The only thing that would change would be the radar service being terminated, as the pilot was asked to contact the tower. If the pilot were on a visual approach with Circle to land, he would be on a visual approach, which is still and IFR procedure.
Now, even if you take out the instruction to contact the tower, the approach procedure (again, including the Circle to Land) would still be an IFR procedure. The radar approach would end after the circle to land, as well as radar service.
BL.