Failure is always an option. 7.81/10 2018-02-21 43 daqiqa.HDDrone deliveries are on their way. But are those fast-spinning blades just an accident waiting to happen? And is the U-2 really the toughest aircraft in regular use to fly and land?Yil: 2018Studiya: Discovery, SBSMamlakat: Australia, United States of America, Ireland