Cessna pilot reported an near midair collision with an aircraft that did not know where it was at an...

Narrative:

I was flying a C150 in the pattern for runway 22 at jvl. I was number two on 2-3 mile final at about 900 feet. The aircraft in front of me reported '[callsign] going missed' and immediately made a hard right turn and climb. I immediately queried them as to the reason of their go-around due to the notable evasive action. They responded that traffic [an ercoupe] had just passed underneath them. I immediately began a climbing right turn to attempt to avoid the traffic; which I could not see. About 15 seconds later; I sighted the ercoupe coming straight at me; about 100 feet below. I initiated an immediate climb to build space. They passed underneath me and continued through the final approach course. At the point of closest approach; I estimate the ercoupe passed within 100 feet horizontally and 200 below me. Following the miss; I reported the position of the ercoupe to jvl tower (they had asked the ercoupe where they were and the ercoupe had not responded) and rejoined final for a landing.I believe what caused the issue was the ercoupe incorrectly reporting their position throughout their attempt to land at jvl and the tower's lack of radar capability. The ercoupe reported numerously that he was in the left downwind for 22; when in reality it appears he was in a very wide left downwind for 36. Because tower only could rely on the position reports coming from the aircraft (which were incorrect); they had no idea where the ercoupe was until we reported his position heading directly up the final approach course. To rectify this issue; I believe that the tower at janesville needs increased surveillance capabilities and as always pilots need to remain proficient in their ability to navigate the airport environment. Of note is the fact another near midair collision occurred a couple minutes later at jvl involving two separate aircraft (described in another report from one of the pilots involved); which I believe can also be partially attributed to the tower not being able to keep up with the traffic due to lack of radar capability and the base turns being pushed 3+ miles from the airport; making it hard for tower to keep up with who was who.

Original NASA ASRS Text

Title: Cessna pilot reported an NMAC with an aircraft that did not know where it was at and had reported a different position in the traffic pattern of JVL.

Narrative: I was flying a C150 in the pattern for runway 22 at JVL. I was number two on 2-3 mile final at about 900 feet. The aircraft in front of me reported '[Callsign] going missed' and immediately made a hard right turn and climb. I immediately queried them as to the reason of their go-around due to the notable evasive action. They responded that traffic [an Ercoupe] had just passed underneath them. I immediately began a climbing right turn to attempt to avoid the traffic; which I could not see. About 15 seconds later; I sighted the Ercoupe coming straight at me; about 100 feet below. I initiated an immediate climb to build space. They passed underneath me and continued through the final approach course. At the point of closest approach; I estimate the Ercoupe passed within 100 feet horizontally and 200 below me. Following the miss; I reported the position of the Ercoupe to JVL tower (they had asked the Ercoupe where they were and the Ercoupe had not responded) and rejoined final for a landing.I believe what caused the issue was the Ercoupe incorrectly reporting their position throughout their attempt to land at JVL and the tower's lack of radar capability. The Ercoupe reported numerously that he was in the left downwind for 22; when in reality it appears he was in a very wide left downwind for 36. Because tower only could rely on the position reports coming from the aircraft (which were incorrect); they had no idea where the Ercoupe was until we reported his position heading directly up the final approach course. To rectify this issue; I believe that the tower at Janesville needs increased surveillance capabilities and as always pilots need to remain proficient in their ability to navigate the airport environment. Of note is the fact another NMAC occurred a couple minutes later at JVL involving two separate aircraft (described in another report from one of the pilots involved); which I believe can also be partially attributed to the tower not being able to keep up with the traffic due to lack of radar capability and the base turns being pushed 3+ miles from the airport; making it hard for tower to keep up with who was who.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1642801
Time
Date	201905
Local Time Of Day	0601-1200
Place
Locale Reference	JVL.Tower
State Reference	WI
Environment
Light	Daylight
Aircraft 1
Make Model Name	Cessna 150
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Visual Approach
Flight Plan	VFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Flight Plan	VFR
Person 1
Function	Single Pilot
Qualification	Flight Crew Commercial
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 530 Flight Crew Type 90
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 100 Vertical 200

Cessna pilot reported an near midair collision with an aircraft that did not know where it was at and had reported a different position in the traffic pattern of jvl.