MBB-BK 117 All Series
Flight Crew Commercial; Flight Crew Rotorcraft
Communication Breakdown; Situational Awareness
ATC Issue All Types; Conflict NMAC; Deviation - Altitude Excursion From Assigned Altitude
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Airspace Structure; Human Factors; Procedure
During cruise flight at 3;000 ft. a traffic alert was issued by Approach Control. He stated 'Crossing traffic at 11 o'clock 1 mile; 200 ft. below you at 2;800 ft.'. He also stated unverified since he had no two way communication with the traffic he had pointed out to me. Again; he called 'traffic at 11 o'clock; 1/2 mile; 200 ft. below you at 2;800 MSL'. At this point the TCAS started alerting me to a potential collision and since we have no RA capabilities I took the evasive action of a cyclic climb until I was approx. 3;300 ft. I still did not have the crossing traffic in sight. Shortly thereafter; a small single engine Cherokee airplane flew directly underneath us. I am convinced he never saw us and since he was not talking to Approach Control he had no idea he had become a conflict for us. ATC had no way to verify if he had the correct altimeter setting and I am convinced had I not initiated a climb we would have had a potential collision at cruise speed. ATC did everything they could to warn us; and our equipment gave me another clue of a potential problem but until corrective action was taken; the conflicting traffic was not spotted until it would have been too late. Always use Approach Control and the radar service they provide even if you are not landing at their primary airport. If this crossing traffic had simply been on frequency and been radar identified; this event would never have happened. Trust your equipment and know how to interpret the data that is being presented. Since we do not have RA capability; you must determine altitude of the traffic by looking at the target displayed altitude and making a decision about a climb; turn or descent. The system will not present the solution on the VSI as a RA system will do.
Helicopter pilot reported a NMAC with a VFR aircraft after Approach issued traffic alert.