Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Communication Breakdown
Conflict NMAC
Flight Crew Took Evasive Action
Aircraft; Human Factors
I was flying a direct route from our base in ZZZ to pick-up a patient at the hospital in ZZZ1.  I was at 1;000 feet MSL with autopilot engaged.  I had noticed that there was another aircraft on TCAS about 10 NM from me but did not have a visual.  Their direction indicated that they were east of us and flying west (we were headed in a generally southern heading).  At 5 NM I alerted my crew that there was an aircraft out around the 10-11 o'clock position and that I did not have them in sight yet.  There was no response on frequency (a general helicopter frequency for avoidance and awareness).  We did finally get a visual confirmation at approximately 1 mile or so of separation (with them at our 10 o'clock position) and it appeared that we had converging vectors.  Still; nothing on the radio and they did appear to be maneuvering to avoid us. Turning would not have been sufficient to separate the aircraft so I began a rapid climb (over 500 FPM) and the aircraft passed directly underneath us with about 300 feet or so of vertical separation (we were rapidly climbing past 1;300 feet MSL).  Afterwards we still got no communication or acknowledgment from the other aircraft.
Pilot reported a NAMC with another aircraft.