If you are approaching a runway for landing that is narrower than you are
accustomed to seeing, you will experience the illusion of being too high.
The smaller looking runway is interpreted by your mind to be farther away than
it is in reality. The pilot has the tendency to fly a lower than normal
approach, in an attempt to make the runway look normal. This could place
the aircraft in an unsafe proximity to terrain and obstructions.
On landing, the pilot may have a desire not to level the airplane for landing at
all, being surprised when the wheels suddenly strike the ground.
The opposite is true on a wider than normal runway, which creates the appearance
of being very close with its large size. Pilots have the tendency to fly
high and try to level the airplane for landing when still at a considerable
If the runway is sloping upwards, it creates the appearance that you are
descending to the runway at a steep angle. This creates the desire to fly
a low, shallow approach in an attempt to make the runway look like one that
isn't sloped. A low, shallow approach is dangerous, since it could place
the airplane in unsafe proximity to terrain or obstructions. Additionally,
flying a shallow approach places you in a position where you would be unable to
make the runway if your engine should suddenly fail.
If the runway slopes downward, it will appear as if you are coming in at a
shallow angle. This creates the tendency to fly high.
Featureless terrain is a very hazardous and visual illusion. Pilots are
used to seeing the ground move below them, giving visual altitude cues. At
higher altitude, these cues go away. Pilots unconsciously associate the
lack of these visual cues to mean they are at altitude. There are a lot of
atmospheric and terrain conditions that can create a featureless visual field.
For example, descending to land at an airport near a shoreline. A lot of
accidents have happened when visibility is somewhat restricted at night in rural
areas. The common picture is the pilot seeing nothing but the approaching
Not receiving these visual warning clues that the airplane is getting too close
to the ground, the pilot will simply descend into the ground. The pilot is
completely surprised upon impact with terrain or obstructions. The lucky
ones come away with some dings on the airplane and a few branches stuck in the
Make sure you follow airport lighting systems that provide you with vertical
guidance to the runway. Follow instrument indications. Situational
awareness includes awareness of your altitude, the airport elevation, and the
elevations of surrounding terrain and obstructions as you make your approach.
Be very careful when descending into an airport surrounded by featureless
terrain. Controlled flight into terrain is the number one cause of
Haze creates the illusion of being at a greater distance from objects on the
ground and in the air.
Rain can create the illusion of greater than actual height above the ground. The pilot who does not recognize this illusion will fly a low approach.
A false horizon can be perceived by the pilot as a result of patterns of ground lights, stars, or sloping cloud formations. The pilot desires to align the aircraft with the false horizon, which is perceived as the actual horizon.
Inexperienced pilots often have a tendency to make approaches and landings at
night with excessive airspeed. Pilots must be aware of this tendency and
concentrate on making night approach and landing in the same manner as during