Incident Overview
On an unspecified date, the pilot of a Piper PA-38, registered N2603B, contacted Addison Airport tower from 10 miles north, requesting landing clearance. The tower cleared the aircraft to 'break... east' and enter a left downwind for Runway 15. Two minutes later, the pilot of a Piper PA-31, registered N182TC, called inbound from the south and was cleared to continue inbound for a left downwind for the same runway.
Flight Paths
Recorded radar flight data revealed that the PA-38 did not execute the 'break east' as instructed. Instead, it eventually paralleled the downwind traffic flow in the opposite direction. Meanwhile, the PA-31 proceeded inbound as cleared.
Separation
The PA-38 passed under the PA-31 with an estimated vertical separation of 50 to 100 feet. The incident involved two aircraft: a PA-38 (single-engine) and a PA-31 (twin-engine).