(Copyright Gary Larson, The Far Side)
This week’s article is sponsored by Aeroclass.org and Axial.aero:
You must have seen funky images on social media like Facebook or LinkedIn. Examples that playfully trick your mind. They are very common and there are many chirpy illustrations of optical illusion.
An innocent one is when you look off into the distance, objects seem closer together as they become further away. For example, the outside borders of a road or railroad appear to converge as they recede into the distance. We all know this. But for pilots, it’s not that straightforward. There are many types of illusions and causes of spatial disorientation, and combined with gravity, that can have grave consequences. Not all of these had been tackled in flight simulator-based training for lack of mechanical engineering and hyper-realism-based technology. This has now changed and companies like Axial Aero are leading the way.
Read on to find out more about spatial disorientation simulators for jet fighter, civil, and even eVTOL pilots.
There are three main types of optical illusions including literal illusions, physiological illusions and cognitive illusions. All 3 types of illusions have one common thread: The perception of the image or sensation given to the brain doesn't measure up.
But before we dive into that, what is spatial orientation really, and how does it work?
Spatial orientation is the ability to maintain body orientation and posture in relation to the surrounding environment (i.e., physical space) at rest and during motion. We, as humans, have evolved to maintain spatial orientation on the ground. There are three physiological systems that team up to allow humans to orient themselves in space:
Eyes (vision)
Inner ears (the vestibular system), and more precisely the liquid in the canals
Seat of the pants (the proprioceptive system), related to sensing gravity.
All 3 of them can fool the brain. Especially when they work against each other, which happens mostly when we’re carried in the air.
The literal illusions are the optical ones. They are related to eyes and thus visual cues. Most conventional flight simulators are based on visual cues because they provide 80% of the senses (sensory inputs) pilots need to maintain orientation. They look out their windows and onto their instruments.
The problem is when they can’t. Because the pilots can’t see outside, or what they see is distorted by other senses and the brain’s functions. It’s the 20% of the senses are overlooked by flight simulators tackling the 80%, while the remainder is disproportionally leading to risk in real flight carrying passengers and cargo.
So, let’s tackle the 20% behind the most risks.
First, let’s look at the 12 types of illusions using a few practical examples and then move on to what new solutions bring to the fore:
Autokinetic illusion: This gives you the impression that a stationary object is moving in front of the airplane’s path; it is caused by staring at a fixed single point of light (ground light or a star) in a totally dark and featureless background. This illusion can cause a misperception that such a light is on a collision course with your aircraft.
Blackhole illusion: Flying an overwater approach or an approach over darkened areas creates the illusion that the aircraft is at a higher altitude than it actually is, causing pilots to fly a lower-than-normal final approach.
Somatogyral illusion, such as a ‘Lean’: If the aircraft enters an unnoticed, prolonged turn gradually, then suddenly returns to level flight, the leans may result. The gradual turn sets the fluid in the ears (semi-circular canals) in motion, and rotational acceleration of two degrees per second (or less) cannot be detected. Once the aircraft suddenly returns to level flight, the continued fluid motion gives the sensation the aircraft is banking in the opposite direction of the turn that just ended; the aviator may attempt to correct the misperception of the vertical by banking into the original turn. The lean is considered the most common form of spatial disorientation.
Coriolis illusion: A powerful tumbling sensation (vertigo) can result if the pilot moves their head too much during instrument flight. This is called Coriolis illusion. Because the semi-circular canals are set in three different axes of rotation, if the aviator suddenly moves their head during a rotational acceleration, one canal may abruptly start to detect an angular acceleration while another ceases, resulting in a tumbling sensation.
(Source: Capt. Rameshkrishnan [“Krish”], Co-Founder of Axial Aero)
Causes of Illusions
Good spatial orientation on the ground relies on the use of visual, auditory, vestibular and proprioceptive sensory information. They are influenced differently by the three-dimensional environment of flight, and unfamiliar to the human body. Traditional flight simulators use 6 DOF (‘Degrees of Freedom’) to mimic flight. That’s Pitch, Roll, and Yaw in both directions.
(Source: PilotFriend.com)
But conventional flight simulators are ill-equipped to effectively simulate spatial disorientation as their effectiveness is based on visual cues being primary. The platforms they use have six jacks that can move the replica cockpit, mounted on the platform, in any of the six degrees of freedom. But the mechanics are part of its limitations. There are many movements in real life it cannot mimic:
The initial acceleration of the vehicle being simulated cannot move without reaching their ‘limit stops’ so an artificial stop is reached using a technique crew do not notice.
After the initial acceleration, the jack movement is gradually decreased, eventually to zero (“washout phase”), contradicting reality.
The motion platform is reset to a neutral position but at a rate below a threshold crew can sense, whereas in real flight it can be the opposite.
What is fundamentally limiting is that the simulators rely on visual cues.
Without vision, 75% of the remaining inputs regarding spatial orientation comes from the vestibular system, and 25% come from the proprioceptive receptors.
How do we simulate that?
(Source: Axial Aero)
Next-Gen Flight Simulators
In order to train jet fighter and commercial pilots better, the next-generation of flight simulators must provide more realism in (1) actual use of air space as well as (2) spatial disorientation.
The first can be achieved by network-connected platforms that communicate with aircraft operating in real time and other simulators, and enable AR and VR. The simulator would be flying in real traffic with dynamic use of air space. This will be crucial for eVTOL flight training, too.
Second, for spatial disorientation, mechanical limitations of the simulator platforms must be removed, so they can accommodate 360-degree movement and inverted flight. This will allow the unsimulation of the senses, such as those described above triggered by liquid in the inner ear canals (vestibular system) and gravity (proprioceptive system).
un- + simulated officially means “real”, “authentic” and “not simulated”. It is a word that is actually used in some industries
The Axial Aero full flight and full envelope simulator is an example of the latest achievement in mechanical and AI engineering and a perfect candidate for all possible applications. It fulfils sophisticated and modern needs, such as:
Ability to reproduce actual experienced forces (including negative ‘G’) due to 360° rotational freedom around all 3-axes.
Ability to simulate multiple aircraft models/variants using the same simulator (swap instruments, use software with different use case application), including jet fighters, civil aircraft, helicopters, and eVTOLs.
Meet ICAOs mandated UPRT (Upset Prevention & Recovery Training) to handle out-of-normal envelope aircraft behavior.
Ability to connect and network with other aircraft and simulators in real time.
Ability to generate all real and potential spatial disorientation sensations.
The recognition of the need for effective training to counteract spatial disorientation and recover from this is paramount to preventing disastrous accidents in the future. The flight simulators still in use today are incapable of providing this. And more practice flying (too routine) is not better than modern technology and is furthermore not conducive for positive climate action.
Facilitating better training at a reduced cost are clearly the way forward for companies like Axial Aero that go beyond the current Level-D Full Flight Simulator (FFS) providers. If you want to know more about this fascinating company, contact me or the company founders, Ramesh Krishnan, or Srikanth Tiyyagura.
Wishing you all a wonderful day from the Laurentian ski slopes, which are open up here!
Ricardo
Montreal, Tuesday, 13 December 2022
Feel free to contact me for questions, comments, or a chat: ricardo DOT pilon AT millavia DOT com or for startup and VC assistance, ricardo AT pomonaworld DOT com.
[*] Note: A thank you to Capt. “Krish” for providing insightful inputs that helped me learn and write this article.