What follows is a message that I had received some months ago which I had
subsequently posted to TIPS for a thread on visual illusions and flying. This
information may be of interest to you in light of the recent tragedy involving
JFK, Jr. If you are teaching a course in sensation and perception or some
other related matter, what follows may be of some use. Unfortunately, toward
the end of the message a couple of small sections seemed to have been cut out,
but still much of the material can be easily followed without difficulty.
---------------
Folks, I forwarded some of the messages (without identify ingindividuals who
posted them) on flying phenomena to a friend of mine who is an aviation buff
and he sent me the following. Please note that to most (some?; many?) of you
this may only be remotely related to teaching.
A wierd sort of perceptual distortion.
In aviation this is called "Spatial Disorientation" This happens when flying in
clouds without outside visual references to the horizon or when flying in a
dark moonless night. During pilot training instructors drill pilots to trust
the instruments and not to follow the feedback received from their bodies.
Pilots in training practice what is called "unusual attitudes" The student is
instructed to close their eyes and lower their head, the instructor then
proceeds to put the airplane in mildly extreme attitudes such as turning dives
or climbs, the student tries to follow what the airplane is doing, but after a
few seconds looses track of what the airplane is doing, they may think the
airplane is turning leftand climbing when in reality it may be diving and
turning in the opposite direction, after a few seconds of this the instructor
tells the student to look up and take control of the airplane, the has to react
quickly, assess what the airplane is doing by looking at the instruments and
exercise a quick recovery. During the "checkride" which is the final test with
an FAA Designated Examiner, the student needs to demonstrate that he/she can
recover from an unusual attitude within the limits set by the FAA.
The FAA has a training device called the Spatial Disorientation Chamber, this
is an enclosed cockpit which is mounted on a hydraulic system which allows the
instructor to move and shake the simulator in many different directions, the
student enters the simulator and tries to control the "airplane" to maintain
straight and level flight, it's extremely difficult and rarely is a student
successful in keeping the simulator within limits let alone keep their
breakfast in their stomach!
The following information was extracted from the "FARs"Federal Aviation
Regulations: 8-1-5 ILLUSIONS IN FLIGHT
a.Introduction 1.Many different illusions can be experienced in-flight. Some
can lead to spatial disorientation. Others can lead to landing errors.
Illusions rank among the most common factors cited as contributing to fatal
aircraft accidents.
b.Illusions Leading to Spatial Disorientation
1. Various complex motions and forces and certain visual scenes encountered
in-flight can create illusions of motion and position. Spatial disorientation
from these illusions can be prevented only by visual reference to reliable,
fixed points on the ground or to flight instruments.
2.The leans - An abrupt correction of a banked attitude, which has been entered
too slowly to stimulate the motion sensing system inthe inner ear, can create
the illusion of banking in the opposite direction. The disoriented pilot will
roll the aircraft back into its original dangerous attitude or, if level flight
is maintained, will feel compelled to lean in the perceived vertical plane
until this illusion subsides.
(a)Coriolis illusion - An abrupt head movement in a prolonged constant-rate
turn that has ceased stimulating the motion sensing system can create the
illusion of rotation or movement in an entirely different axis. The disoriented
pilot will maneuver the aircraft into a dangerous attitude in an attempt to
stop rotation. This most overwhelming of all illusions in flight may be
prevented by not making sudden, extreme head movements, particularly while
making prolonged constant-rate turns under IFR conditions.
(b)Graveyard spin - A proper recovery from a spin that has ceased stimulating
the motion sensing system can create the illusion of spinning in the opposite
direction. The disoriented pilot will return the aircraft to its original spin.
(c)Graveyard spiral - An observed loss of altitude during acoordinated
constant-rate turn that has ceased stimulating the motion sensing system can
create the illusion of being in a descent with the wingslevel. The disoriented
pilot will pull back on the controls, tightening the spiral and increasing the
loss of altitude.
(d)Somatogravic illusion - A rapid acceleration during takeoff can create the
illusion of being in a nose up attitude. The disoriented pilot will push the
aircraft into a nose low, or dive attitude. A rapid deceleration by a quick
reduction of the throttles can have the opposite effect, with the disoriented
pilot pulling the aircraft into a nose up, or stall attitude.
(e)Inversion illusion - An abrupt change from climb to straight and level
flight can create the illusion of tumbling backwards. The disoriented pilot
will push the aircraft abruptly into a nose low attitude, possibly intensifying
this illusion.
(f)Elevator illusion - An abrupt upward vertical acceleration,usually by an
updraft, can create the illusion of being in a climb. The disoriented pilot
will push the aircraft into a nose low attitude. An abrupt downward vertical
acceleration, usually by a down-draft, has the opposite effect, with the
disoriented pilot pulling the aircraft into a noseup attitude.
(g)False horizon - Sloping cloud formations, an obscured horizon, a dark scene
spread with ground lights and stars, and certaingeometric patterns of ground
light can create illusions of not being aligned correctly with the actual
horizon. The disoriented pilot will place the aircraft in a dangerous attitude.
(h)Autokinesis - In the dark, a static light will appear to move about when
stared at for many seconds. The disoriented pilot will lose control of the
aircraft in attempting to align it with the light. Airplane begins to drop
(because the wings are no longer lifting directly parallel to the Earth's
surface). This is slightly incorrect. A plane does not necessarily have to fly
parallel to the earth to be flying "straight and level" The reason the plane
starts descending in a turn if no action is taken to correct this tendency is
because the vertical component of lift is reduced as the horizontal component
of lift is increased. The vertical component of lift is produced when power is
applied to the engine and incombination with the design of the airplane it
overcomes gravity, the horizontalcomponent of lift is produced when the
ailerons are moved to initiate a turn, the horizontal component of lift
overcomes the tendency of the airplane to fly straight by overcoming
centripetal force. In other words when the space shuttle is flying straight up
and not turning it is considered to be flying straight and level!
Then get the hell out of the clouds, by doing a slow 180 degree turn back the
way you came. Then hope the FAA doesn't find out. Why? If the pilot is
instrument rated, current and in an IFR flight plan there is nothing wrong with
flying in the clouds. If this is the case the thing to do is fly by the
instruments and continue on.
When a pilot starts training the first certificate that he/she received allows
him/her to fly under VFR rules (Visual Flight Rules) this means that the pilot
can only fly when certain weather conditions exist. It is true that alot of
accidents happen when a VFR rated pilot continues to fly into deteriorating
weather and eventually ends up in the clouds, in this situation the above
statement is 100% true. The second rating that a pilot works for is the IFR
rating (Instrument Flight Rules). Once a pilot passes the IFR checkride he/she
is qualified to fly in IMC (instrument meteorological conditions) this includes
flying in the clouds which is perfectly safe and legal. Pilots have
occasionally been known (or so I've been told) to actually fly upside down
without realizing it. And even if it's not true, it makes an interesting story
Ever try to close your eyes and hang upside down? Do you think you would know
that you are upside down because of the effect of gravity? I suspect the above
statement to be an exaggeration.
Aviation accidents. The article noted that almost ALL crashes involve serious
pilot error - usually a series of bad judgements - but that many are attributed
to mechanical problems by the time they reach the media
The NTSB investigates every single aviation accident, 90+percent of the times
the accident is attributed to pilot error, the media usually gets their
information from the NTSB reports and they usually report it as is. Most of
the accidents are reported as "pilot error, contributing factor a totally
destroyed control system"
The recent Swiss Air accident is a perfect example, the cockpit was burning and
filled with smoke, the last six minutes of the flight even the cockpit voice
and data recorders were inoperative, there are people in aviation already
blaming the pilot for not being able to land the airplane safely, could you
drive your car on fire with all controls inoperative safely to the nearest gas
station? Pilots take exception to the common trend in the NTSB to blame every
accident on pilot error.
>>>> some mechanical problem ("the rudder broke") than to some series of bad
judgements ("first, he set the wrong way-point into the GPS, and didn't
recognize his mistake until his fuel was low. At that point he chose an
unfamiliar airport to stop for fuel and misread the tower frequency. While
trying to read the correct frequency, he allowed his airspeed to drop and had a
classic stall-and-spin into the ground...")
This is an interesting subject which is commonly studied inaviation, most
accidents are not as a result of one big mistake, but rather a series of small
mistakes leading to an accident. The above is a perfect description of what
usually happens before an accident occurs. The FAA places strong emphasis on
CRM (cockpit resource management) which encourages cooperation with pilots and
co-pilots to share the load of flying an airplane and double check everything
that the pilot/co-pilot does by the other party.
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Miguel Roig, Ph.D. Voice: (718) 390-4513
Assoc. Prof. of Psychology Fax: (718) 442-3612
Dept. of Psychology [EMAIL PROTECTED]
St. John's University [EMAIL PROTECTED]
300 Howard Avenue http://rdz.stjohns.edu/~roig or
Staten Island, NY 10301����������http://area51.stjohns.edu/~roig����
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