Helicopter Pilot reported a NMAC with another helicopter on approach while practicing auto-rotations.
Synopsis
Helicopter Pilot reported a NMAC with another helicopter on approach while practicing auto-rotations.
Narrative
I had been doing pattern work in Aircraft X helicopter to train a new pilot for part 135. We were doing left closed patterns to Runway 21. On every pattern we were either told to stay south of alpha taxiway or we remained south of alpha taxiway without being told. Not one time did we fly north of alpha taxiway. This happens so that we don't become an issue for aircraft coming into Runway 8. We were cleared for the option most times; if I remember correctly. Sometimes we were cleared to land. Not 100% sure. A lot of the times the clearance for the option or to land was given to us on the take-off roll. We had done a lot of normal patterns and then we requested 1;000 ft. or high patterns for 180 degree auto rotations. We had accomplished a few of these patterns. At one point; the Tower had extended our upwind for an incoming aircraft. At some point [Company] Helicopters was coming in for a northwest arrival after coming back from Honoli'i. Tower gave us a heads up and we had them insight. I was used to aircraft on the northwest arrival crossing over between the intersections of Runways 3 and 8. I had lost sight of [Company]. I remember being cleared for the option so we entered our 180 degree auto-rotation while abeam the same spot we had entered a few times before. As we turned into the wind during our 180 degree auto-rotation on short final for the 1;000 ft. markers of Runway 21 I saw [Company] in front and above us. I didn't have to make any corrections to my flight path to avoid the aircraft and it seemed a safe distance from where we were. I am not sure if I was cleared for the option or not. I believe to remedy this situation in the future Tower could have kept us south of alpha taxiway (which we were) and any helicopter going into the Cat (Commuter Air Terminal) on a northwest arrival to be routed north of Runway 8 until clear of the extended centerline of Runway 3-21. Other than that I don't believe an aircraft should be cleared across a runway that pattern work is being done at unless ATC has us extend our upwind until the aircraft in across the runway; have us land; or have us do left or right 360s.
Second reporter narrative
During a training flight we were practicing 180 auto-rotation's to Runway 3 at the Hilo international airport. During our second or third auto-rotation; upon turning 180 degrees we saw a [Company] helicopters high and to our right and then across the runway high and in front of us. We were following ATC instruction to the best of our knowledge. The traffic separation seemed too close but did not ever seem like we were on a collision course.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.