Small Aircraft; High Wing; 1 Eng; Fixed Gear
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 0.45
Confusion; Situational Awareness
ATC Issue All Types; Airspace Violation All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Air Traffic Control Separated Traffic; Flight Crew FLC complied w / Automation / Advisory
Procedure; Airspace Structure
Aircraft X was inbound to MRI. He is a primary only target without a transponder and Mode C altitude readout. I instructed them to enter right downwind for runway 25 at MRI. EDF tower was working Aircraft Y to runway 6 at EDF.  I observed Aircraft Y on the downwind to RWY 6 at EDF close to our airspace boundary.  At that time I issued the traffic to Aircraft X and Aircraft X said he had them in sight. I issued a cautionary wake turbulence advisory and told Aircraft X that Aircraft Y would pass off his side inbound to EDF. At that time I could see Aircraft Y turning on the base to EDF RWY6. Aircraft Y spilled into MRI airspace putting them in close proximity to Aircraft X.  A short time later EDF tower called me and told me that Aircraft Y was getting a TCAS advisory and doing a right 360 degree turn in my airspace. Luckily we had no other aircraft inbound from the Northwest and the Northwest portion of our airspace can become very congested with inbound and outbound aircraft.The Northwest corridor is too close to EDF final putting small aircraft in very close proximity to large and heavy aircraft in and out of EDF. By adding the chunk of airspace from the MRI/EDF gate extension or not allowing heavy aircraft to stay in the closed pattern at EDF may alleviate this hazard. Also if EDF could coordinate prior to heavy aircraft using the RWY6 pattern at EDF it would give MRI the opportunity to be aware there may be a spill over into our airspace.
An aircraft responding to an RA in the traffic pattern at EDF entered the MRI Class D airspace without clearance.