C150 pilot reported a near midair collision with a helicopter in the pattern at ZZZ.

Attributes
ACN	1657912
Time
Date	201906
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
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	None
Aircraft 2
Make Model Name	Helicopter
Flight Phase	Cruise
Flight Plan	None
Person 1
Function	Instructor Single Pilot
Qualification	Flight Crew Flight Instructor
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 100

Narrative:

On left base runway xx at ZZZ. Helicopter appeared to be patrolling nearby pipeline not on common frequency flew approximately 100 feet below aircraft turning final.

Original NASA ASRS Text

Title: C150 pilot reported a NMAC with a helicopter in the pattern at ZZZ.

Narrative: On left base Runway XX at ZZZ. Helicopter appeared to be patrolling nearby pipeline not on common frequency flew approximately 100 feet below aircraft turning final.

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.