Rainmaker Know-how’s bid to deploy cloud-seeding flares on small drones is being met by resistance from the airline pilots union, which has urged the Federal Aviation Administration to contemplate denying the startup’s request until it meets stricter security pointers.

The FAA’s choice will sign how the regulator views climate modification by unmanned aerial techniques going ahead. Rainmaker’s wager on small drones hangs within the steadiness.

The Air Line Pilots Affiliation (ALPA) advised the FAA that Rainmaker’s petition “fails to reveal an equal degree of security” and poses “an excessive security threat.”

Nonetheless, Rainmaker CEO Augustus Doricko mentioned an e-mail that all the union’s objections are primarily based on solely the general public discover, slightly than personal paperwork submitted to the FAA that define all the firm’s security information and threat mitigations.

Rainmaker is looking for an exemption from guidelines that bar small drones from carrying hazardous supplies. The startup filed in July, and the FAA has but to rule. As a substitute, it issued a follow-up request for info, urgent for specifics on operations and security.

In its submitting, Rainmaker proposed utilizing two flare sorts, one “burn-in-place” and the opposite ejectable, on its Elijah quadcopter, to disperse particles that stimulate precipitation. Elijah has a most altitude of 15,000 toes MSL (measured from sea degree), which sits inside managed airspace the place industrial airliners routinely fly. Drones want permission from Air Visitors Management to fly inside this bubble.

Rainmaker’s petition says it would function in Class G (uncontrolled) airspace until in any other case licensed. ALPA notes the submitting doesn’t clearly state the place flights would happen or what altitudes could be used. Nonetheless, Doricko mentioned the paperwork submitted to the FAA disclosed that along with the flights being constrained to a max altitude of 15,000 toes MSL, they are going to be performed in airspace that’s predetermined to be secure by aviation authorities, “voiding any cheap concern about excessive altitude flight or airspace coordination.” ALPA didn’t reply to TechCrunch’s requests for remark. 

The union additionally objects to the flares themselves, citing issues about international object particles and hearth security. ALPA factors out that the petition doesn’t embody trajectory modeling of the ejectable casings or evaluation on the environmental impacts of chemical brokers.

“Relating to their objection to using flares, unbiased our bodies like this administration’s EPA and a number of state departments of pure sources have studied the dispersion and environmental security of supplies utilized in cloud seeding for over 70 years and by no means discovered any adversarial impact from cloud seeding,” Doricko mentioned.

Sam Kim, Rainmaker’s aviation regulatory supervisor, mentioned the corporate respects the pilot’s union and hopes to “proceed to strengthen our relationship with the group,” however claimed the objection “reveals a lack of knowledge of why Rainmaker has filed for this exemption.”

“Our use of flares in unmanned techniques is solely for analysis functions in a managed flying atmosphere and isn’t part of our bigger ongoing operations,” Kim added.

Doricko mentioned {that a} typical Rainmaker operation disperses 50-100 grams of silver iodide, and much lower than that in a flight with flares, whereas one hour of flight of a industrial airplane releases kilograms of uncombusted unstable organics, sulfur oxides, and soot – considerably extra materials than a Rainmaker op.

“Rainmaker is excited by doing the most effective, accountable atmospheric analysis and is thus evaluating flares to our proprietary aerosol dispersion system that can exchange flares and solely emit silver iodide. ALPA’s objection to this exemplifies their restricted understanding of our CONOP, all of which comprises in depth threat mitigations within the personal docs that the FAA is reviewing now,” Doricko mentioned.

“Relating to ALPA’s issues about coordination with aviation authorities and airspace, our flight operations include broadcasting indicators, intentional coordination with native ATC, licensed pilots, and a collision avoidance system that includes digital and bodily observers,” he mentioned.

Nonetheless, Rainmaker says the flights will happen over rural areas and over properties owned by non-public landlords “with whom Rainmaker has developed shut working relationships.”

Cloud-seeding already occurs in the present day, largely within the western U.S., with crewed airplanes flown in coordination with state companies. Ski resorts fee the operations to assist maintain their runs white, and irrigation and water districts fly them to construct snowpack within the winter to assist feed their reservoirs throughout the spring soften.

The overall observe of cloud seeding dates again to the Nineteen Fifties. By spraying small particles into sure clouds, scientists discovered they might induce precipitation. Sometimes, cloud-seeding operations use silver iodide for the particles, principally as a result of they mimic the form of ice crystals.

When a silver iodide particle bumps into droplets of water which might be super-cooled, they trigger the droplet to quickly freeze as a result of its water is already beneath the freezing level. As soon as the ice crystal kinds, it could develop rapidly if situations are proper, quicker than a liquid water droplet would in comparable circumstances. Plus, the fast progress helps the crystals stick round longer than a water droplet, which could evaporate earlier than it has an opportunity to fall as precipitation.

Rainmaker’s twist — doing this work with drones as a substitute of pilots — may show safer in the long run. The corporate factors out that the flight profiles are tightly bounded, overseen by a distant pilot and educated crews, over rural areas, with different security checks in place.

What occurs subsequent hinges on whether or not the FAA thinks these mitigations are enough. Nonetheless it’s determined, the company’s response will seemingly set the tone for novel cloud-seeding approaches.

9/13/2025: The story has been up to date to incorporate Rainmaker’s feedback from Augustus Doricko, founder and CEO, and Sam Kim, Rainmaker’s aviation regulatory supervisor.