S A F E T YA
ccording to the Federal
Aviation Authority between
5 to 10% of all general
aviation accidents can
be attributed to spatial
disorientation, and 90%
of these accidents are fatal.
Despite the FAA figures, attributing an accident to spatial
disorientation is difficult given that pilots are usually unaware
they are disoriented when it is happening and therefore
unable to report on their condition, believes Doug Carr, the
vice-president of regulatory and international affairs at the
US National Business Aviation Association (NBAA). Even so,
he says, “I believe it is not uncommon for accidents at the
lighter end of the general aviation spectrum to have spatial
disorientation as a contributing factor in some way.”
Understanding the biology
It is first important to understand the body’s systems
that enable us to stay oriented to understand why a pilot
gets disoriented, says Dr Braden McGrath, research
professor at the Department of Human Factors and
Behavioral Neurobiology at Florida’s Embry-Riddle
Aeronautical University.
“We have three concordant redundant systems that keep
us oriented in the world – our eyes, our inner ear and our
skin-muscle joint system,” says McGrath. “They work really
well together, but when you go flying two of the systems -
the inner ear and the skin-muscle joint system - no longer
work effectively.”
Without the help of these two systems, responsibility for
staying spatially oriented falls to our eyes. For pilots this
means scanning the horizon and their visual instruments
for data on the plane’s orientation, says McGrath.
“The problem comes when we don’t have a
view of the horizon or we get distracted from our
instruments,” he says. “Then the brain can get
information from the incorrect sources.”
These incorrect sources are the forces acting on
the body during flight. When a plane accelerates
or decelerates swiftly, enters a roll, pitch or yaw
movement or some other maneuver, the inner ear –
also known as the vestibular system – can confuse the
resultant forces for the pull of gravity. Simply put, says
McGrath, “the body misperceives down.”
Somewhat counter-intuitively spatial disorientation can
often pose more of a danger when the forces are less
severe says McGrath “When you’re pulling 3G you know
you’re pulling 3G, so you’re going to be more alert. But a
lot of spatial disorientation mishaps happen when the force
is closer to 1G, because in those circumstances it’s much
easier to assume that the force you’re feeling is normal
gravitational pull.”
Instrument flying
The main counter measure to the problem of spatial
disorientation is proficiency in instrument flying, says Carr.
An age-old problem
Spatial disorientation has a storied history in aviation and is implicated
in some of its most famous disasters.
In the 1959 crash that killed the singer Buddy Holly a combination
of inexperience and cloud cover probably led to the pilot of the light
aircraft suffering spatial disorientation, according to the official
accident report.
A similar conclusion was drawn about the 1999 death of John F
Kennedy Jr – the son of the former US president – who was killed along
with his wife and sister-in-law when the Piper Saratoga he was piloting
crashed in the Atlantic close to Martha’s Vineyard.
In the Kennedy incident investigators found that the crash had been
immediately preceded by a “graveyard spiral”, a phenomenon common
to spatial disorientation accidents when the pilot inadvertently enters
into a spiral dive while believing they are flying with wings level.
A number of on-board instruments – such as the
attitude indicator – provide vital data about the plane’s true
orientation. Thorough instrument training teaches pilots not
only proficiency in these instruments but also “to disregard
signals their body is giving them about the
orientation of the aircraft that are likely
incorrect,” says Carr.
“Spatial disorientation is
much more of an issue among
new pilots,” says Carr. The
business aviation industry
is therefore providing
information and outreach
“The problem comes
when we don’t have a
view of the horizon or
we get distracted from
our instruments”
Dr Braden McGrath, Embry-Riddle
Aeronautical University
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to pilots. “You’ll see it
everywhere in the training
curriculum,” he says. “It’s not
something that the industry just sits by and waits for
to happen.”
Even so, training doesn’t make a pilot immune to the
risk. For example, Japan recently confirmed that the sudden
crash of a Japanese F-35 stealth fighter in the Pacific Ocean
in April 2019 was likely the result of spatial disorientation.
Despite having 3,200 hours of flight experience, accident
investigators concluded that the jet’s pilot, Major Akinori
Hosomi, lost his bearings, downing the flight in the sea
Above: The belt has miniature
tactile actuators sewn inside
it that vibrate at different
locations and intensities along
a pilot’s torso
Above right: The vest interfaces
directly with the skin-muscle
joint system, accessing a part
of the cognitive system that
responds reflexively