As humans, we constantly perceive things: sounds, sights, smells and movement. Some of these perceptions are accurate while some others are erroneous. A frequent perception mistake occurs at night when we mistakenly identify a planet as approaching aircraft. Likewise, as pilots we sometimes encounter the "black hole illusion" or glideslope miscalculations over sloping terrain.

What do you think are some effective countermeasures pilots can use to counteract illusions like these?