TOKYO – A drone helicopter has made an emergency rooftop landing after developing engine trouble while measuring radiation over Japan's tsunami-hit nuclear power plant.
Plant operator Tokyo Electric Power Co. said no major damage occurred Friday to the aircraft or the reactor building roof. It was still being assessed further.
The U.S.-made drone has been used regularly to inspect hard-to-access areas of the Fukushima Dai-ichi plant crippled by the March 11 earthquake and tsunami.
A Japanese robot also failed to complete its debut mission because of mechanical problems.
