Abstract: A turbine head assembly is provided for use with an aerial tow reel assembly. The turbine head includes permanently open aft exhaust ports and a turbine assembly upstream of the exhaust port. The turbine head assembly features a housing with an open inlet. A split balanced butterfly valve assembly is provided at the open inlet of the housing. An actuation assembly drives a pair of baffle doors about a vertical axis with the baffle doors being arranged so as to automatically rotate inward into a closed position whenever there is a power outage in flight. This fail-safe feature avoids turbine overspeeding. The actuation assembly is positioned closer to the inlet and the butterfly valve assembly than to the turbine assembly.