Bell Helicopter Textron Undifferentiated or Other Model
Flight Crew Instrument; Flight Crew Commercial
Flight Crew Last 90 Days 100; Flight Crew Total 3700; Flight Crew Type 1200
Confusion
Conflict NMAC
Flight Crew Became Reoriented
Human Factors; Airspace Structure
While in cruise flight on the return leg from Medical Center Hospital; I noticed the shadow of a fixed wing aircraft out the right side of the helicopter at approximately the 2 O'clock position. The shadow was defined and large enough to concern me that this airplane was very close. I let the crew know in a concerned tone of voice that I could see an airplane shadow and asked them to help me locate it. At this time I was approximately 1;000 FT AGL and held my heading and course due to the fact I did not know where the plane was. I watched the shadow out the right door continue to head in a west heading as we were southbound. The paramedic in the left seat announced that he spotted the plane at the 11 O'clock position above us but immediately lost it. At this time the shadow started a left turn and was tracking in the same direction of our heading before the nurse in the right seat announced it was at 3 O'clock low and was turning and flying below us. Both crew members were able to keep a visual on it as it flew directly under us then continued to the east. The medevac crew continued to track it until it was out of site. As we continued to home base we discussed the chain of events and the factors that contributed to this being a confusing situation. My initial thought was that the position of the sun made it hard to see the plane in the first place and the fact that I was using the center post as a sun block also created a blind spot. When I saw the planes shadow it appeared to be straight and level but none of us knew where it was except for the fact it was very close due to the size and definition of its shadow. The plane was spotted above us and then lost. The shadow then changed direction and the plane was spotted again flying below us; creating even more confusion and concern. We all agreed that the pilot of this small high wing plane most likely never saw us and was in the start of a descending left hand turn as it passed over the top of us at no more than 100 FT and the flew underneath of us at approximately 300 FT below us.
Helicopter pilot describes a NMAC with a high wing aircraft at 1;000 FT AGL as the helicopter pilot is returning to base. The aircraft is first detected by its shadow in close proximity to the helicopter shadow.