BY ORDER OF THE SECRETARY OF THE AIR FORCE AIR FORCE ...

AFMAN 11-217V1 3 JANUARY 2005 371
dispelled. When they gripped the controls in the usual manner, the apparent
control anomaly returned. Clearly, the pilot must be sufficiently knowledgeable
about the giant hand illusion to suspect it when the possibility of spatial
disorientation exists.
17.4. Types of Spatial Disorientation. There are three distinct types of spatial
disorientation. Type I is unrecognized spatial disorientation; the pilot is unaware that
anything is wrong and controls the aircraft in response to the false sensations of attitude and
motion. Type II is recognized disorientation; the pilot is aware that something is wrong, but
may not realize that the source of the problem is spatial disorientation. The pilot usually
suspects an instrument malfunction, and in a few cases it has been reported that the pilot will
“tap” on the display glass to see if it is stuck (even with Cathode Ray Tubes (CRTs)). Type
III is incapacitating spatial disorientation; the pilot knows something is wrong, but the
physiological or emotional responses to the disorientation are so great that the pilot is unable
to recover the aircraft. This may result from the pilot’s inability to obtain visual information
due to blurring of vision (nystagmus), however, there have been several reports of this
occurring during air refueling or flying fingertip. An example of each type of disorientation
follows:
17.4.1. Example of Type I SD. The last of four aircraft took off on a daytime sortie in
the weather, intending to follow the other three in a radar in-trail departure. Because of a
navigational error shortly after takeoff, the pilot was unable to acquire the other aircraft
on radar. Frustrated, the pilot elected to intercept the other aircraft knowing they would
be on the arc of the Standard Instrument Departure. The pilot proceeded directly to that
point, scanning the radar diligently for the blips that should be appearing at any time.
Meanwhile, after climbing to 4,000 feet above ground level, the pilot entered a 2,000-
3,000 foot per minute descent as the result of an unrecognized, 3-degree nose-low
attitude. After receiving requested position information from another member of the
flight, the mishap pilot suddenly made a steeply banked turn, either to avoid a perceived
threat of collision or to join up with the rest of the flight. Unfortunately, the pilot had
already descended far below the other aircraft and was going too fast to avoid the ground.
This mishap resulted from unrecognized, or Type I, disorientation. The specific illusion
responsible was the somatogravic illusion created by the forward acceleration of the
aircraft during takeoff and climbout. Preoccupation with the radar scanning
compromised the pilot’s instrument crosscheck to the point where the false vestibular
cues were able to dominate orientation information processing. Having accepted this
inaccurate spatial orientation “feeling,” the pilot controlled the aircraft accordingly until
it was too late to recover.
17.4.2. Example of Type II SD. On a clear day with unlimited visibility and a distinct
horizon, the pilot was flying a two-on-two air combat training mission over water. After
a series of roll reversals during the engagement, the pilot thought the aircraft was straight
and level when the pilot acquired the bandits slightly low and to the right. In reality, the
pilot was in a 90-degree left bank looking up at the other aircraft. To ensure a successful
separation, the pilot rolled to the left and pulled to raise the nose slightly. Actually, the
pilot had rolled almost inverted and pulled down. What alerted the pilot to being
disoriented was that the aircraft sounded as if it was going very fast (this is the beginning
of Type II—the pilot suspects something to be wrong, in this case it was an aural cue).