Helicopter
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 105.7; Flight Crew Total 565.6; Flight Crew Type 130
Communication Breakdown; Confusion; Physiological - Other; Situational Awareness
Aircraft Equipment Problem Critical; Conflict Airborne Conflict
Flight Crew Took Evasive Action; General Maintenance Action
Environment - Non Weather Related; Aircraft
I was doing flight instruction coming back from doing off-airport training. Winds were calm; visibility was unlimited; sky was clear; [and the] sun was starting to set. Throughout the day; I observed fixed wing traffic using both Runway 30 and 12 for takeoff and landing as the winds were calm. I was making radio calls to enter a 45 for extended left base for Runway 12 about 4 miles out. During my approach to left base; I did not hear any aircraft make any radio calls for takeoff; I did see one airplane depart Runway 30 about three miles ahead during my approach to left base. He was departing the area to the northwest; he was no factor. I was at 500 FT AGL; started on my left base and descent for parallel Taxiway 12; made my radio call (Airport Traffic; Helicopter; is on a left base for parallel Taxiway 12; airport traffic.) Before turning; I cleared the area to the right; forward; and when I looked to the left; the airplane was airborne and in a climb headed in my direction; I immediately banked left to avoid what might have been a collision and made right traffic for parallel 30 and landed upon arrival to the parking area. The fixed wing pilot parked also and said I was not talking on the radio; which I was the whole flight. Upon further inspection of my radio after the flight; I discovered that the coaxial cable that runs the radio antenna had disconnected from the radio during flight which is why I was not transmitting during my radio transmissions during various stages of the flight around the airport. The closest distance to the airplane at any given time during the incident was no more than 500 FT. Contributing factors included: Glare on the windscreen as the sun was at its lowest point on the horizon limiting visibility on left base; aircraft using both runways for take off and landing; and an unknowingly disconnected and non-transmitting radio. Corrective actions: upon aircraft sighting; turned to remain clear of fixed wing flow. Adjusted and secured radio coaxial cable to avoid any future in-flight radio disconnection.
A helicopter pilot took evasive action from an aircraft departing a CTAF airport and thought the other pilot was not making position reports in response to his but after landing discovered his radio not connected to its antenna.