Incident
at LONDON ON (CYXU)
An ITPS (Canada) Ltd. Aero Vodochody L39C (ST42) from London, ON (CYXU) to London, ON (CYXU), inbound for an overhead break at CYXU, came in close proximity of an IFR aircraft on final, a Waterloo-Wellington Flying Club Cessna 172RG (C-GPIQ) on a flight to London, ON (CYXU), with a high rate of closure. Traffic was passed to C-GPIQ and multiple times to ST42. C-GPIQ reported traffic in sight. After completing an overhead break, and during the briefing to the CYXU tower to reopen, ST42 started to turn base abeam VFR traffic, an Aeolus Flight Academy Cessna 172M (C-GPAS) from London, ON (CYXU) to London, ON (CYXU), that was within close proximity, but was stopped by the tower controller.