Reliable Robotics has flown a small cargo airplane with no humans on board for the first time, marking a significant milestone for autonomous aviation. The uncrewed flight test, which Reliable Robotics announced on December 6, took place at Hollister Municipal Airport in California on the morning of November 21.
The company’s modified Cessna 208B Caravan safely executed a 12-minute test flight—including taxi, takeoff, and landing—without any human intervention, although the aircraft was monitored by a remote pilot at a control station about 50 miles (80 kilometers) from the airport in Mountain View. A 360-degree camera inside the cockpit recorded a video of the flight, which Reliable Robotics released on YouTube.
Company CEO Robert Rose told AIN that the FAA granted Reliable Robotics a special airworthiness certificate permitting it to fly the experimental uncrewed aerial system (UAS) for research and development purposes with some limitations. “We didn’t have to shut down the airspace, but we did have to notify the Northern California control center when we were operating,” he said. The company was required to file a notice to air missions (notam) and fly within a specified boundary that was within the visual line of sight (VLOS) of observers on the ground.
Reliable Robotics is developing its autonomous flight control system with the ultimate goal of enabling uncrewed cargo flights. The first iteration of this technology that the company plans to commercialize will be an advanced autopilot system for single-pilot operations in crewed aircraft, which is meant to supplement rather than replace onboard pilots. Continuous autopilot engagement reduces the pilot’s workload while making the aircraft safer and more efficient, according to the company.
In July, the FAA formally approved Reliable Robotics’ certification plans for the supplemental type certificate (STC) it will need to begin retrofitting Cessna 208B Caravans with the advanced autopilot system. According to Reliable Robotics, the certification plans leverage existing regulations and do not require any special conditions or exemptions. Rose said he expects to have the STC for single-pilot operations in hand in the 2024-2025 timeframe, and that certification for uncrewed operations will come a year or two later.
The uncrewed version will include additional detect-and-avoid capabilities as well as a communications system designed specifically for remote piloting. Reliable Robotics is developing its own air-to-air radar that the company says will be able to track all airspace users regardless of whether they have transponders. Rose told AIN that the radar system will enable the company to begin flight testing beyond visual line of sight (BVLOS) without a pilot on board “in the near future.”
Rose explained that flying the uncrewed aircraft with no pilot on board was an important milestone on the path to certifying the fully autonomous flight control system. “Integration of the aircraft into the airspace is an equal challenge to getting the equipment certified, and there are a lot of things procedurally that we need to work through internally and with the FAA before we can go field this technology in the real world,” he said.
Reliable Robotics has not done any subsequent uncrewed flights since November 21, but the company plans to continue uncrewed flight testing in 2024, Rose said. “There are a number of follow-on tests that we intend to do,” he said. “This first test is a very important step forward in verifying system performance and validating the requirements.”
As Reliable Robotics works to certify its autonomous flight control system, the company is already flying cargo commercially using a small fleet of unmodified Cessna airplanes. It holds a Part 135 operator’s certificate and regularly hauls FedEx packages around the Albuquerque, New Mexico area. These cargo flights provide Reliable Robotics with opportunities to collect the flight data it needs to develop and refine the autopilot system.
Rival start-ups Xwing and Merlin are also developing autonomous flight control systems for Cessna Caravans while operating small cargo airlines. Xwing’s Part 135 air carrier service transports cargo for UPS in a fleet of unmodified Cessnas, while Merlin is using the airplanes to deliver cargo to rural communities in northern New Zealand through a partnership with Freightways New Zealand. So far those companies have only flown their experimental autonomous airplanes with safety pilots on board.
Like Reliable Robotics, Merlin is taking an incremental approach to certification with single-pilot operations preceding uncrewed flights. Xwing, however, is taking a different approach and plans to launch with uncrewed operations directly rather than using single-pilot operations as a stepping stone. But large, remotely-piloted aircraft are considerably more complicated to certify than an autopilot, and it’s not yet clear how or when regulators will approve those uncrewed operations.