Landing Errors due to Optical Illusions

Landing Illusions

Illusions created in flying an airplane can kill. This post provides pilots with information to recognize conditions that lead to optical illusions and how to cope while flying.

• You can anticipate the possibility of visual illusions when you fly into a new airport destination.  Especially at night and/or when adverse weather conditions exist. Make sure you consult Jepp Charts on runway slope, terrain and lighting.
• Increase your scan of the altimeter during all approaches in day or night conditions.
• If possible, consult with a pilot that actually landed at the new airport destination. He may provide important information. If not, try and inspect the the airport yourself before flying there.
• Use Visual Approach Slope Indicators (VASI) or Precision Approach Path Indicators (PAPI).These systems help visual reference in adverse conditions where the horizon is obscured or visually missing. Another source is an electronic glideslope, if available.
• Use a visual descent point (VDP) found on many non-precision instrument approach procedure charts. These help protect you from beginning your approach too soon or too late.
• If emergency or other activity distracts you from your usual approach procedures the chance of an accident  increases.
• Maintain, by practice, proficiency in landing procedures.

In addition to the sensory illusions due to misleading inputs to the inner ear vestibular system, a pilot may also encounter various visual illusions during flight.

Illusions rank among the most common factors cited as contributing to fatal aviation accidents. That is one of the safety factors stressed in my posts.

Sloping cloud formations, an obscured horizon, a dark scene spread with ground lights and stars and certain geometric patterns of ground light can create illusions of not being aligned correctly with the actual horizon. these may cause you to approach too high or too low. Serious matters depending on obstructions before the runway or running out of runway if too high.

Various surface features and atmospheric conditions encountered in landing can create illusions of being on the wrong approach path. Landing errors due to these illusions can be prevented by anticipating them during approaches, inspecting unfamiliar airports before landing, using electronic glideslope or VASI systems when available, and maintaining proficiency in landing procedures.