I believe the new frontier for light airplanes is fly-by-wire, or more likely, electronic enhancement of flying qualities and envelope protection. And homebuilders are the people in a perfect position to pioneer those advances.
Light airplane design and technology is very mature. People have been working to improve the speed, efficiency and safety of airplanes flying from 150 to 300 knots for more than 80 years. As an industry we know how to make good airplanes in that performance range and future improvements will be incremental, a few percentage points at a time, at best.
But electronic technology is still exploding. Nobody can predict what will be possible, and practical, using electronics in the coming years. And it is electronics applied to how airplanes fly that can advance the performance and safety of light airplanes more than any change in design or materials.
It’s already happening in large, fast airplanes where fly-by-wire is the norm for any new design. Fly-by-wire (FBW) uses computers to interpret the control inputs of pilots to then send a command to servos to actually move the flight controls. FBW can be more redundant than conventional mechanical and hydraulic control systems because multiple computers and wire paths can be installed, along with redundant servos to move the controls.
Control redundancy is not a significant concern in light airplanes, but electronic management of how the airplane flies could be an enormous benefit. The FBW computers can be programmed to make the airplane perfectly stable in all flight regimes. That means the airplane would constantly return to straight and level after being upset by turbulence, or maneuvered by the pilot.
An FBW system could also provide envelope protection. For example, let’s say the pilot commands an abrupt attitude change at high airspeed that would threaten to overload the structure of the airplane. The computers would temper the pilot’s input and command only enough control surface movement to take the airframe it its structural limits, but not beyond the limits and break it.
FBW could also prevent the pilot from exceeding both the high and low airspeed limits of the airplane. For example, if the pilot keeps commanding nose up when there is not enough energy available to prevent the airplane from entering a stall, the FBW computers would limit the up elevator travel to prevent a stall no matter how hard the pilot pulls back on the stick.
In its most comprehensive iteration FBW can automatically land the airplane if the pilot were to become disoriented in bad visibility, or if he were incapacitated. Unpiloted UAVs of all sizes make automated flights—including takeoffs and landings—thousands of times a day all over the world. Avionics experts from Rockwell Collins have already configured a Bonanza to land itself, and flown hands off landings. This is not pie in the sky, but technology that is available now and not all that expensive.
True FBW where there is no mechanical link between cockpit controls and the flight controls is unrealistic for a homebuilt at this point, but what is possible, and makes sense to me, is a supervisory electronic system. Computers could generate the commands to enhance stability of the airplane, and to move the controls to protect the flight envelope, while still allowing the human pilot to overpower the servo if the electronic system were to fail.
The FAA is being very cautious when it comes to approving electronically enhanced stability and envelope protection in production light airplanes. Even though loss of control is the single most common cause of serious light airplane accidents, and electronics could help prevent those, the FAA is slow to act. But homebuilders do not have those same FAA certifications restrictions. Builders could include electronic flight control enhancements now because their airplanes are experimental and the electronics can be experimental, too.
Homebuilders are creating a wide variety of attractive and good performing airplanes, and many of those have advanced flat glass avionics. The next step, I think, is to incorporate electronics to enhance the actual flying qualities of the airplane to provide stability not achievable through natural aerodynamic means, and add the safety of protecting the pilot from exceeding the design envelope. Electronic flight control enhancement would always be standing by to right an airplane if a pilot loses control in the clouds, and even automatically fly an approach to a runway. If builders show the way, maybe the FAA will see the light and help make electronic flying qualities enhancements, and safety, more available to all categories of airplane.