C172 pilot reported an near midair collision with a helicopter in the vicinity of hwo airport.

Narrative:

I was giving a tour along the shoreline. I reported my position on the published beach frequency. I alerted the frequency that I would be crossing over to the shoreline and descending to 800 feet and would be proceeding southbound along the shore. I listened to the frequency and heard no traffic in my vicinity. I looked carefully for traffic; but saw none. Before I had reached the shoreline; a helicopter (larger and faster than me) cut across my path. I could not divert to the right. He was passing left to right and towards me. I slowed down; pushed the nose down and tipped the plane to the left. If the helicopter had not have seen me I would have hit it. I could not have maneuvered out of the way in time to avoid it. He was way too close; within 20 feet. He pulled to the right and descended. That area is extremely high traffic. I had all of my lights on. The helicopter had no lights on. Sometimes the lights are helpful for spotting traffic. The helicopter was not using the published beach frequency. The airspace is uncontrolled. Sometimes hwo will give you advisories until you reach the shoreline; but not always. Today they were unable. If the other aircraft had been on the frequency they might have heard my call and been more vigilant. I will have my passengers help me to look for traffic next time.

Original NASA ASRS Text

Title: C172 pilot reported an NMAC with a helicopter in the vicinity of HWO airport.

Narrative: I was giving a tour along the shoreline. I reported my position on the published beach frequency. I alerted the frequency that I would be crossing over to the shoreline and descending to 800 feet and would be proceeding southbound along the shore. I listened to the frequency and heard no traffic in my vicinity. I looked carefully for traffic; but saw none. Before I had reached the shoreline; a helicopter (larger and faster than me) cut across my path. I could not divert to the right. He was passing left to right and towards me. I slowed down; pushed the nose down and tipped the plane to the left. If the helicopter had not have seen me I would have hit it. I could not have maneuvered out of the way in time to avoid it. He was way too close; within 20 feet. He pulled to the right and descended. That area is extremely high traffic. I had all of my lights on. The helicopter had no lights on. Sometimes the lights are helpful for spotting traffic. The helicopter was not using the published beach frequency. The airspace is uncontrolled. Sometimes HWO will give you advisories until you reach the shoreline; but not always. Today they were unable. If the other aircraft had been on the frequency they might have heard my call and been more vigilant. I will have my passengers help me to look for traffic next time.

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	1328314
Time
Date	201601
Local Time Of Day	1201-1800
Place
Locale Reference	OPF.Airport
State Reference	FL
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Aircraft 2
Make Model Name	Helicopter
Flight Phase	Cruise
Person 1
Function	Instructor Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 200 Flight Crew Total 1200 Flight Crew Type 1100
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 20 Vertical 0