Cessna 340/340A
Flight Crew Multiengine; Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 100; Flight Crew Total 4600; Flight Crew Type 180
Situational Awareness; Communication Breakdown
Conflict NMAC
Human Factors
I was cleared to fly a visual approach to runway 32 at PLN by Minneapolis center. I announced my position relative to the airport on the unicom/CTAF frequency of 123.0 at 14 nm; 4 nm; and entering left base for the runway. I was monitoring both center frequency and unicom frequency. I did not hear at any time another aircraft broadcast any position reports for landing at the same airport. I did scan the area for additional traffic and did not see any. While on the base leg of my approach nearing where I was going to turn to the final approach segment; a Beechcraft Baron went right over the top of my aircraft approximately 50 ft from my aircraft. I continued on my heading to the north east and circled back and landed behind the aircraft involved with me in the near mid-air accident. The other aircraft departed after I landed. I suspect the aircraft was involved with some type of flight training. My opinion on what caused this problem is twofold. My inability to see the other plane ahead and his lack of position reports on the unicom/ctaf frequency while approaching the airport. In addition; the lack of a standard pattern flown by the other aircraft was most likely a contribution to the near mid-air. The other plane was not in contact with Center or I would not have been cleared for a visual approach. I did not hear any broadcasts of positions by any other planes from the time I started broadcasting my position when I was 14 miles out. I did hear the plane give taxi position broadcasts once on the ground but otherwise no communications whatsoever. Thankfully; this incident was just a lesson and not a fatal accident.
C340 pilot; on a visual approach to Runway 32 at PLN; reports a NMAC with a BE58 on a straight in approach to the same runway. The reporter had made position reports on the CTAF and entered on the left base while the other pilot made no position reports.