General Atomics President Explains Autopilot Fault In YFQ-42 Mishap

BERLIN—A glitch that caused a YFQ-42 Dark Merlin aircraft to crash in April came from a newly designed, high-performance autopilot developed for the Collaborative Combat Aircraft (CCA) prototype, General Atomics Aeronautical Systems Inc. President David Alexander tells Aviation Week.

The April 6 incident prompted the U.S. Air Force to pause flight tests with the Dark Merlin prototype until May 21 for a safety review. General Atomics Aeronautical Systems Inc. (GA-ASI) previously confirmed that review found that an “autopilot miscalculation for the weight and center of gravity of the aircraft” was at fault. In an interview here at the ILA Berlin Air Show, Alexander elaborated on the context for the autopilot error.

“We have close to 700,000 sorties and 9.3 million flight hours on our standard autopilot, and that's a highly tuned autopilot for what I would call our [medium-altitude] long-endurance platforms that don't do heavy maneuvers,” Alexander said. “This new autopilot is more of a fighter autopilot, where people are pulling G’s and snap-turns and not over-G-ing the platform.”

“We've only got like 43 flights on that autopilot,” Alexander continued. “There was an issue with it. We found it, we fixed it. The customer says move quick, and we're moving quick.”

The YFQ-42 comes with a fly-by-wire control system with layers of envelope protections, which must be programmed into the non-linear inversion autopilot.

“To protect the aircraft, you put all the limits on the commands,” Alexander said. “And then those commands have to be scaled with speed, and that part gets really complicated, so this new autopilot takes care of all that for you automatically.”

The GA-ASI candidate for the Air Force’s CCA Increment 1 production program is now back in flight test.

“It's unfortunate, but you’ve got to get right back up and get in the saddle and get moving,” Alexander said.