The skies are becoming ever more populated with aircraft flying to exotic destinations or taking business travelers to find new streams of revenue. Each passing year, new pilots are trained in safety standards and regulations to avoid mid-air collisions, and many still rely on their eyes to survey their immediate surroundings. They need to learn, however, to trust their instruments more in certain cases to avoid collisions as well.
There have been instances in the past when aircraft have collided because the opposing plane was in the blind spot of the other. Just like with cars, airplanes have blind spots in which an incoming aircraft might be located out of sight of the pilots. In this instance, many modern commercial aircraft have proximity sensors and collision avoidance systems that will alert the pilot of an impending collision. There are been some collisions in the past where the pilot either ignored the warnings or depended on their own eyes instead of relying on the aircraft's sensors.
It is also possible that a pilot might be distracted by operational reasons. It's possible that the pilot is speaking to their co-pilot, going over systems to ensure they are functioning properly, or even preparing for landing. These can be critical times when the pilot is distracted and not paying attention to the view outside their window. During these times, a pilot needs to be trained to listen to and trust the plane's sensors which will alert them of oncoming planes.
It doesn't happen often but there have been instances of commercial aircraft colliding due to human error. One of the most famous instances of this happening was a mid-air collision between a DHL aircraft and a commercial airliner colliding due to human error. The two planes were unknowingly on a collision course and even though each plane's collision avoidance system did alert the pilots, only one pilot listened to it, while the other listened to air-traffic control. If the pilots in both planes had heeded their plane's sensors, the collision would have been prevented.
Pilots with a broad scope of training in both visual detection and being aware of their surroundings at all times, and learn to trust their aircraft's collision avoidance systems when they are preparing for landing or performing other operational necessities, will be more likely to bring their aircraft home safely. This must start at the pilot training level and continue through the pilot's career. To learn more about potential flight dangers and how to avoid them, contact an aviation school.