B737 captain reported an near midair collision with a flight of 3 helicopters on approach.

Attributes
ACN	1729427
Time
Date	202002
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Next Generation Undifferentiated
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Helicopter
Flight Phase	Cruise
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 218 Flight Crew Type 2292
Events
Anomaly	ATC Issue All Types Conflict NMAC

Narrative:

Established on ILS runway xxl at approximately 1600 ft. AGL a TCAS RA was received resulting in close proximity to several orange canyon tour helicopters. After clear of conflict a missed approach was executed. There were no traffic calls from ATC; we were on an instrument approach at the FAF and got three traffic contacts below our nose not in sight and slightly to the right; flying about 150 degrees opposite our flight path in approximately a one mile trail column formation. If not for TCAS we may have had a midair; on final approach; on an instrument approach! It took at least three calls to tower to establish that we were missed approach [and] responding to RA. Our perception was that he was busy directing [another] aircraft to clear the runway. Then tower stated that the RA was ok because the helicopters were on a published route. I told him I was was on a published instrument approach! And if it was ok why did I get an RA? He responded switch approach frequency. Unbelievably unsafe situation.

Original NASA ASRS Text

Title: B737 Captain reported an NMAC with a flight of 3 helicopters on approach.

Narrative: Established on ILS Runway XXL at approximately 1600 ft. AGL a TCAS RA was received resulting in close proximity to several orange canyon tour helicopters. After clear of conflict a missed approach was executed. There were no traffic calls from ATC; we were on an instrument approach at the FAF and got three traffic contacts below our nose not in sight and slightly to the right; flying about 150 degrees opposite our flight path in approximately a one mile trail column formation. If not for TCAS we may have had a midair; on final approach; on an instrument approach! It took at least three calls to Tower to establish that we were missed approach [and] responding to RA. Our perception was that he was busy directing [another] aircraft to clear the runway. Then Tower stated that the RA was ok because the helicopters were on a published route. I TOLD HIM I WAS WAS ON A PUBLISHED INSTRUMENT APPROACH! And if it was ok why did I get an RA? He responded switch approach frequency. Unbelievably unsafe situation.

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.