How Advanced Autopilots Make Airplanes Safer When Humans go AWOL
It’s a cliché in movies that whenever an airplane’s pilots are incapacitated, some distraught crew member queries the self-loading freight if any of them know how to fly a plane. For small airplanes we picture a hapless passenger taking over the controls so that a heroic traffic controller can talk them through the landing procedure and save the day.
Back in reality, there have been zero cases of large airliners being controlled by passengers in this fashion, while it has happened a few times in small craft, but with variable results. And in each of these cases, another person in the two- to six-seater aircraft was present to take over from the pilot, which may not always be the case.
To provide a more reliable backup, a range of automated systems have been proposed and implemented. Recently, the Garmin Emergency Autoland system got its first real use: the Beechcraft B200 Super King Air landed safely with two conscious pilots on board, but they let the Autoland do it’s thing due to the “complexity” of the situation.
Human In The Loop
Throughout the history of aviation, a human pilot has been a crucial component for the longest time for fairly obvious reasons, such as not flying past the destination airport or casually into terrain or rough weather. This changed a few decades ago with the advent of more advanced sensors, fast computing systems and landing assistance systems such as the ILS radio navigation system. It’s now become easier than ever to automate things like take-off and landing, which are generally considered to be the hardest part of any flight.
Meanwhile, the use of an autopilot of some description has become indispensable since the first long-distance flights became a thing by around the 1930s. This was followed by a surge in long-distance aviation and precise bombing runs during World War II, which in turn resulted in a massive boost in R&D on airplane automation.
While the the early gyroscopic autopilots provided basic controls that kept the airplane level and roughly on course, the push remained to increase the level of automation. This resulted in the first fully automatic take-off, flight and landing being performed on September 22, 1947 involving a USAF C-54 Skymaster. As the military version of the venerable DC-4 commercial airplane its main adaptations included extended fuel capacity, which allowed it to safely perform this autonomous flight from Newfoundland to the UK.
In the absence of GNSS satellites, two ships were located along the flight path to relay bearings to the airplane’s board computer via radio communication. As the C-54 approached the airfield at Brise Norton, a radio beacon provided the glide slope and other information necessary for a safe landing. The fact that this feat was performed just over twenty-eight years after the non-stop Atlantic crossing of Alcock and Brown in their Vickers Vimy airplane shows just how fast technology progressed at the time.
Nearly eighty years later, it bears asking the question why we still need human pilots, especially in this age of GNSS navigation, machine vision, and ILS beacons at any decently sized airfield. The other question that comes to mind is why we accept that airplanes effectively fall out of the sky the moment that they run out of functioning human pilots to push buttons, twist dials, and fiddle with sticks.
State of the Art
In the world of aviation, increased automation has become the norm, with Airbus in particular taking the lead. This means that Airbus has also taken the lead in spectacular automation-related mishaps: Flight 296Q in 1988 and Air France Flight 447 in 2009. While some have blamed the 296Q accident on the automation interfering with the pilot’s attempt to increase thrust for a go-around, the official explanation is that the pilots simply failed to notice that they were flying too low and thus tried to blame the automation.
For the AF447 crash the cause was less ambiguous, even if took a few years to recover the flight recorders from the seafloor. Based on the available evidence it was clear by then that the automation had functioned as designed, with the autopilot disengaging at some point due to the unheated pitot tubes freezing up, resulting in inconsistent airspeed readings. Suddenly handed the reins, the pilots took over and reacted incorrectly to the airspeed information, stalled the plane, and crashed into the ocean.
One could perhaps say that AF447 shows that there ought to be either more automation, or better pilot training so that the human element can fly an airplane unassisted by an autopilot. When we then consider the tragic case of Helios Airways Flight 522, the ‘ghost flight’ that flew on autopilot with no conscious souls on board due to hypoxia, we can imagine a dead-man switch that auto-lands the airplane instead of leaving onlookers powerless to do anything but watch the airplane run out of fuel and crash.
Be Reasonable
Although there are still a significant number of people who would not dare to step a foot on an airliner that doesn’t have at least two full-blooded, breathing human pilots on board, there is definitely a solid case to be made for emergency landing systems to become a feature on airplanes, starting small. Much like the Cirrus Airframe Parachute System (CAPS) – a whole-airplane parachute system that has saved many lives as well as airframes – the Garmin Autoland feature targets smaller airplanes.
After a recent successful test with a HondaJet, this recent unscheduled event with the Beechcraft B200 Super King Air twin-prop airplane turned out to be effectively another test. As the two pilots in this airplane were flying between airports for a repositioning flight, the cabin suddenly lost pressurization. Although both pilots were able to don their oxygen masks, the Autoland system engaged due to the dangerous cabin conditions. They then did not disengage the system as they didn’t know the full extent of the situation.
This effectively kept both pilots ready to take full control of the airplane should the need have arisen to interfere, but with the automated system making a textbook descent, approach and landing, it’s clear that even if their airplane had turned into another ghost flight, they would have woken up groggy but whole on the airstrip, surrounded by emergency personnel.
Considering how many small airplanes fly each year in the US alone, systems like CAPS and Autoland stand to save many lives both in the air and on the ground the coming years. Combine this with increased ATC automation at towers and elsewhere such as the FAA’s STARS and Saab’s I-ATS, and a picture begins to form of increased automation that takes the human element out of the loop as much as possible.
Although we’re still a long way off from the world imagined in 1947 where ‘electronic brains’ would unerringly fly all airplanes and more for us, it’s clear that we are moving in that direction, with such technology even within the reach of the average owner of an airplane of some description.