Close at Hand

Active control sidesticks—traditional control yoke feel with a space-age twist
technology, aviation, g500, g600, avionics
Written By J. Mac McClellan

Piloting a jet airplane demands an extremely high level of knowledge acquired through specific training resulting from a type rating and years of experience. But, particularly during periods of high workload or stress, experienced pilots also instinctively rely on the kinesthetic sense honed by thousands of hours in the air to guide flight control inputs and receive the control feedback that the airplane is responding as expected.

That is the challenge for any company designing a modern jet cockpit: how to take advantage of new technology to reduce pilot workload and improve aircraft performance without also eliminating the human side and immeasurable value of thousands of hours of real-world flying.

A fully automated cockpit (one that overrides pilot input), which some jet airplane makers have opted for, does a great job of handling a routine flight. But the automation largely eliminates the active participation of the pilot. And that has the potential to become a problem if the unexpected eventually happens—a scenario the flight computer hasn’t been programmed to handle because the circumstance had never been conceived.

That’s why Gulfstream rejected the automated cockpit concept that eliminated pilot feedback years ago when the fundamental design of the Symmetry Flight Deck was taking shape for the G500 and G600 jets. In Gulfstream’s view, the new jets must benefit equally from new technology while maximizing the irreplaceable skill and experience of the pilots who fly them.

Before Gulfstream began designing the Symmetry Flight Deck the only available sidesticks—the ones used in other jets—were essentially high-quality video game controllers. A passive control stick robs pilots of all feedback from the airplane that tells us the aircraft is changing speed, attitude or flight path. Those “limp” sticks deprive a pilot of the most fundamental and unmistakable critical flight information: what is felt through the controls. The passive control stick to the nonflying pilot is completely limp, and both control sticks are useless when the autopilot is flying.

The active control sidesticks in the Gulfstream G500 and G600 are a technological quantum leap forward in flight control design—and pilots at FlightSafety International in Savannah, Georgia, already flying the Symmetry Flight Deck in G500 full-motion simulators absolutely love it. The sticks provide artificial feel, which changes based on flight condition and flap configuration, similar to conventional flight controls. And the active control sidesticks are electronically linked so that they both move in unison and in response to autopilot inputs. The tactile and visual input is exactly like traditional flight controls—only better.

OK. That is the design philosophy. But how do the sidesticks feel in actual use? Does an experienced pilot need to learn something new to be familiar and comfortable with the sidesticks in general? I got a chance to find out in Gulfstream’s high-fidelity simulator developed to tailor cockpit controls and refine them for the G500 jets already in flight test.

The answer is the active control sidesticks feel totally natural and behave as expected on the very first try. As I eased my wrist back to raise the nose on my first takeoff roll, the force I felt through the stick was what my experience told me to expect. As the G500 accelerated, I used the trim button under my thumb to adjust the elevator trim to remove the force. Again, exactly as expected.

In Gulfstream’s view, the new jets must benefit equally from new technology while maximizing the irreplaceable skill and experience of the pilots who fly them.

These are the control responses any pilot has experienced since solo. There is nothing new to learn, and thus all of the thousands of hours a new G500 and G600 pilot will have amassed before the new type rating will be applied the first time and every time when flying the new jet.

Gulfstream experimental test pilot Scott Martin, who leads the G500 and G600 cockpit design team, was in the right seat as I flew. When Scott moved his sidestick I could feel the motion in my stick, exactly as I would in any other conventional airplane. I knew what Scott was doing with the controls—he could feel my control inputs—and we could both monitor autopilot control movements when that system was engaged. But in other sidestick jets, we wouldn’t have known who was moving the controls because the sticks are not linked and don’t move together. If one pilot is distracted or even panicked, the other pilot can be powerless to help because his sidestick is limp. But not in the G500 and G600.

The active technology used in the Gulfstream sidesticks is similar to that used for robotic surgery. In the operating room, a surgeon’s hands and fingers move the robotic controls as though the surgeon was actually manipulating the surgical instruments. In reality, the movements (control inputs) are translated by sensors that are more precise and have no tremor to perform the most critical surgical procedures.

The G500 and G600 sidesticks have complete backups within each stick for any component failure. And, of course, the active control sidesticks on each side of the cockpit are independent, so there are multiple backups.

Yes, pilots will earn a new type rating to fly the G500 and G600 because it is different from other Gulfstreams in many ways. But I believe the transition into the new cockpit will be the most natural yet for experienced pilots.

It appears as though Gulfstream has mastered one of the greatest challenges of our lifetime—how to merge the best of human skill and experience with the astonishing capabilities of computers. And when the task is to safely operate the highest performing jet airplanes, there is no more critical issue.

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