Date: 201402
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Night
Aircraft: Helicopter
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Cruise
Airspace: Class E ZZZ
ATC / advisory: Tower ZZZ
Second aircraft: Helicopter
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Situational Awareness; Workload
Anomaly: Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Ambiguous

Narrative: Nine miles north of ZZZ airport [we were] at around 1;000 FT MSL while flying a helicopter. Two other helicopters were also covering the event; all pilots in communications with each other to keep separation. A Police Helicopter; a Medevac Helicopter and a Guard Helicopter were also operating in the area; but all communicating on the helicopter to helicopter air to air frequency. An unidentified helicopter approached the 3 helicopters from the north at what appeared to be same altitude as myself and the other 2 helicopters. Several attempts were made from all of us to reach said aircraft on the helicopter air to air frequency with no such luck. The videographer I fly with pointed the aircraft mounted FLIR camera and identified the aircraft to be a UH-60 Blackhawk helicopter. We ended up having to take evasive action for what now was a head on collision at the same altitude with mentioned UH-60. We moved to the right to avoid the UH-60. All 3 helicopters already on scene took action to avoid the UH-60. It appeared the UH-60 did not see any of us at all even though we all flashed our aircraft landing lights. It appeared to us all the UH-60 forced its way in as to say 'outta my way' or 'was preoccupied' inside cockpit with other tasks; however I find it hard to understand an aircraft flying within city limits the size of X city not paying attention to an area known for its high volume of aircraft especially helicopters both day and night. The only aircraft taking any form of action was the 3 news helicopters. None appeared to be taken from the UH-60. Weather was reported clear with 10 SM miles visibility. No injuries nor damage to any aircraft; but too close of a call.If only one helicopter was at this location hovering with its heading pointed opposite of the 'incoming UH-60' it could have led to loss of several lives. A call was made to ZZZ to see if mentioned unidentified aircraft was in communication with ZZZ ATC; but the Tower Controller's response was 'no; but I see several targets in your area.' After said UH-60 did a flight around the city it flew back north bound and disappeared to the north without ever making a radio call.A call was made by me to an airport UH-60 pilot who said no such aircraft was scheduled at night time on that day. The departure of the UH-60 to the north leads me to believe the aircraft could have been out of a military base.




Synopsis: A helicopter pilot orbiting at 1;000 FT north of ZZZ with two other helicopters; reported a near miss with an apparently military UH-60 which transited north out the area without communicating.