Methods, systems, and apparatus, including computer programs encoded on computer storage media, for a distributed system architecture for unmanned air vehicles. One of the methods includes obtaining information identifying flight information of a UAV, with the flight information including flight phase information or a contingency condition associated with a flight critical module included in the UAV. The obtained information is analyzed, and one or more first payload modules are determined to enter a modified power state. Requests to enter the modified power state are caused to be transmitted to each determined payload module in the one or more first payload modules.