Reliable Robotics has spent nearly ten years developing autonomous flying systems designed for installation on existing aircraft. The latest $115 million infusion gives the Mountain View, California startup additional resources to advance Federal Aviation Administration certification of its autonomous flight technology, a pivotal step that chief executive Robert Rose described as drawing nearer each day.

The round extends the Series D with $90 million in equity led by Nimble Partners plus $25 million in debt from Silicon Valley Bank. The expanded round now stands at $275 million and lifts the company valuation above $1 billion. Additional backers include Gideon Strategic Partners, RockCreek, Geek Ventures, Gold Hill Capital and Sparkwave Capital. Reliable has now raised $380 million overall.

Rose, previously director of flight software at SpaceX and with experience at Tesla and Google, noted steady advancement and daily evidence shared with regulators. Co-founder and chief technology officer Juerg Frefel also brings nearly a decade of engineering work from SpaceX.

In the tightly regulated aviation sector, any movement toward certification of novel technology counts as meaningful progress.

The company is pursuing FAA approval across four interconnected areas tied to autonomous operations.

Its initial offering, continuous autopilot engagement, manages engine start, taxi, takeoff and landing while the pilot stays aboard and interacts via touchscreen. Rose anticipates certification of this first system within 18 to 24 months.

The second milestone, expected in at least three years, shifts the pilot from the cockpit to a ground-control station.

Reliable is also developing its own collision-avoidance radar after legacy suppliers declined involvement. Unlike traditional systems with moving antennas, the solid-state design has no moving parts, offers longer range and higher resolution, and promises lower maintenance and cost.

Rose highlighted recent commercial aviation incidents as heightening operator interest, noting the radar also prevents ground collisions with aircraft or structures. Certification is targeted for the end of 2027.

The final step involves certification of Reliable Airlines, the first carrier approved to operate the autonomous technology. Based in Albuquerque, the airline flies six Cessna Caravans on cargo routes six days a week.

Nimble Partners founder John Burbank emphasized the broad impact, describing the effort as far larger than a single aircraft. He noted the system applies to any airframe and predicted that initial approval will establish the industry standard, much like autonomy in automobiles.