Date: 201912
Local time of day: 1201-1800
Location: ZID.ARTCC, IN
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: PA-28R Cherokee Arrow All Series
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Initial Approach
Airspace: Class E ZOB
ATC / advisory: CTAF SGH
Second aircraft: Beechcraft Twin Turboprop or Jet Undifferentiated or Other Model
Reporter organization: Personal
Reporter function: Single Pilot
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial
Human factors: Communication Breakdown; Time Pressure; Situational Awareness
Anomaly: Conflict Airborne Conflict
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Environment - Non Weather Related; Human Factors; Airspace Structure
Primary problem: Ambiguous

Narrative: I was enroute from SGH; where I had performed several touch and go operations; to ZZZ; where I intended to refuel. Approximately 20-25 minutes earlier; the AWOS at SGH was reporting a ceiling of 1XX00 ft. broken. Prior to that; it had reported a few clouds at 1XX00 ft.; and then scattered clouds at 1XX00 ft. Immediately prior to my encounter with the other aircraft; the AWOS at ZZZ was reporting a ceiling of 2500 ft. overcast. The distance between the two airports is 18.3 nautical miles.Upon my departure from SGH; I decided to fly the RNAV (GPS) Runway XX approach to ZZZ; commencing at the IAF. For practice; I commonly fly instrument approaches under VFR; sometimes working with air traffic control and sometimes not. This day I was not working with ATC. My aircraft is equipped with both ADS-B Out (Stratus ESG transponder) and ADS-B In (Stratus 2i receiver). I navigate with Foreflight installed on an iPad.The initial segment (ZZZZZ to ZZZZZ1) of the ZZZ RNAV (GPS) Runway XX approach is charted at 3000 ft. (MSL); however; I leveled off between 2700 ft. and 2800 ft. to maintain a safe and legal clearance from the overcast layer. I was flying a course of 002 degrees to ZZZZ1 (IAF/IF). Upon reaching ZZZZZ1; the chart indicates a right turn to the inbound course of 0XX2 degrees. Approximately two nautical miles prior to reaching ZZZZZ1; Foreflight displayed the following message: TRAFFIC 1 O'CLOCK; 1 MILE; SAME ALTITUDE. I immediately fixed my attention on that area of the sky; and within a few seconds visually acquired the other aircraft; which appeared to be a King Air 200 or 300 series; coming toward me at a distance I estimate to be approximately mile. I immediately initiated a steep right turn (approximately 50-55 degrees bank) and applied back pressure to maintain altitude. The other aircraft simultaneously initiated a right turn away from me. My attention at that point was focused on ensuring separation from the other aircraft; and I did not immediately notice that I had climbed to approximately 3100 ft. MSL. I noticed a moment later that I had in fact climbed slightly above the bases of the scattered clouds in the vicinity. I was able to maintain the required lateral distance from the clouds; while I descended back to my previous altitude between 2700 ft. and 2800 ft. MSL. I abandonned the approach and flew direct to ZZZ without further incident.I believe the other aircraft was on the RNAV (GPS) Runway 24 approach to SGH; most likely on an instrument flight plan; having descended through the overcast layer at 2500 ft. AGL. Prior to leaving the SGH advisory frequency; I heard another aircraft announce its position inbound on the approach; it might have been that aircraft. It is likely that the aircraft was alerted to my presence by ATC and directed to initiate an evasive turn. I was not actively looking for the aircraft on the SGH approach as I believed its course to be well north of the ZZZ approach. Upon further study of the charts after the flight; I discovered that in fact the SGH Runway 24 approach course intersects two segments of the ZZZ Runway XX approach; one of those at nearly the same altitude. Further; FENLU; the IAF/IF on the ZZZ Runway XX approach where a turn to the inbound course is executed; lies approximately 1.5 nautical miles north east of CEVKI; the FAF on the SGH Runway 24 approach. Aircraft flying the two approaches precisely as charted could be at the same altitude where the approach segments intersect. Where one or both aircraft are under positive control; this may not present a serious problem. However; if both aircraft are VFR and not in communication with ATC; as was the case with me; this is potentially catastrophic.The problem is two-fold: first; even though both pilots might be appropriately announcing their positions; neither pilot would hear the other because they would be on different frequencies. Second; while pilots are typically aware of the potential location of other aircraft operating in the vicinity of the same airport; there is nothing to bring to pilots' attention the potential conflict of aircraft operating to different airports as in this case. With respect to this event; both aircraft were apparently operating in compliance with regulations and procedures. Nevertheless; the two aircraft came dangerously close to one another. I respectfully suggest that this situation deserves further study to determine whether a practical means exists to mitigate the risk inherent in the design of these approaches.




Synopsis: PA-28R pilot reported an airborne conflict while making a VFR practice approach. Pilot believes conflicting aircraft was using a different frequency for a nearby airport.