Despite the general decline in high-altitude reconnaissance RPV use, new mission roles would emerge. In April 1969 a Lockheed EC-121 Super Constellation SIGINT aircraft was shot down in international airspace by North Korean fighters, killing all 31 crew members on the aircraft. This incident led to consideration of using an unmanned drone to do the SIGINT job, resulting in the Model 147TE or Combat Dawn RPV. The Model 147TE's first operational flight was in February 1970, although this flight and those that followed over two months were really just evaluation tests. The tests proved successful and an order for fifteen production Model 147TE drones followed, with the first operational flight of a production 147TE in October 1970.