Flight Crew Flight Engineer; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 250; Flight Crew Total 38000; Flight Crew Type 400
Communication Breakdown
ATC Issue All Types; Conflict NMAC
General None Reported / Taken
Procedure; Human Factors
I reported to Tower 5 miles north; inbound to land. The Tower instructed me to report mid-field downwind; 'your choice right or left downwind.' I said I would report right downwind. I heard no other traffic on the frequency. Just as I was approaching mid-field downwind and about to report downwind; a small aircraft flying opposite direction flew directly overhead; approximately 100 feet above me. At that point the controller cleared me to land. The controller then told the other aircraft; 'sorry about that.' I spoke with the other pilot afterwards; he said he was breaking in an engine and flying orbits near the airport as cleared by the controller. As far as I know; we were the only aircraft in the Class D airspace at the time. The other aircraft was close enough that I could hear his engine as he passed overhead.
GA pilot reported a NMAC during final approach to ONM airport.