Rainmaker Technology’s plan to use small drones for cloud-seeding flares is facing opposition from the airline pilots’ union, which is urging the Federal Aviation Administration to reject the startup’s proposal unless it adheres to more rigorous safety standards.
The FAA’s ruling will reveal the agency’s stance on weather manipulation using unmanned aerial vehicles in the future. The outcome will determine whether Rainmaker’s reliance on small drones can move forward.
The Air Line Pilots Association (ALPA) informed the FAA that Rainmaker’s application “does not provide evidence of an equivalent safety level” and represents “a significant safety hazard.”
Rainmaker is asking for a waiver from current prohibitions on small drones transporting dangerous substances. The company submitted its request in July, but the FAA has not yet made a decision. Instead, the agency has requested more detailed information regarding operational and safety protocols.
In its submission, Rainmaker outlined plans to utilize two types of flares on its Elijah quadcopter — one that burns in place and another that can be ejected — to spread particles that encourage rainfall. The Elijah drone can reach up to 15,000 feet above sea level, placing it within regulated airspace used by commercial flights. Drones must secure clearance from Air Traffic Control to operate in this regulated zone.
Rainmaker’s application states that operations will take place in Class G (unregulated) airspace unless otherwise permitted. ALPA points out that the filing lacks clarity about the specific locations and altitudes where these flights would be conducted. Neither Rainmaker nor ALPA responded to TechCrunch’s inquiries for comments.
The union also raises issues with the flares themselves, expressing worries about debris and fire risks. ALPA highlights that the request omits trajectory analysis for the ejected flare casings, as well as assessments of environmental effects from the chemicals involved.
Rainmaker, however, indicates that drone flights will be limited to rural regions and land owned by private parties “with whom Rainmaker has established strong working partnerships.”
Currently, cloud-seeding is already performed, especially in the western U.S., by human-piloted aircraft working with state authorities. These operations are often commissioned by ski resorts to maintain snow coverage, and by water management districts to increase snowpack for reservoirs ahead of spring runoff.
The concept of cloud seeding dates back to the 1950s. Scientists discovered that releasing fine particles into certain types of clouds could trigger rainfall. Typically, silver iodide is used because its crystal structure closely resembles that of ice.
When a silver iodide particle encounters supercooled water droplets, it prompts them to freeze quickly as the water is already below freezing. The resulting ice crystals can then expand rapidly under the right conditions, growing more swiftly than liquid droplets would. This quick expansion also means the crystals last longer than water droplets, which could evaporate before falling as rain or snow.
Rainmaker’s approach — using drones to perform this task rather than piloted planes — could ultimately enhance safety. The company notes that its flight patterns are strictly controlled, monitored by remote pilots and trained teams, confined to rural airspace, and supplemented by additional safety measures.
The next steps depend on whether the FAA believes these safety precautions are adequate. Whatever the outcome, the agency’s response will likely influence how innovative cloud-seeding strategies are handled in the future.
