One fine Sunday morning last October, my wife and I were winging our way westward across southern Illinois at 3500 feet. We were returning home from a visit to see her mother who was recovering from a fall. The relatively low altitude was to avoid stronger headwinds higher up. The local terrain elevations put us on the edge of the “hemispherical cruising rule.” As always, I was getting flight following from ATC.
The problem was that radar contact had temporarily been lost. That meant I needed to be looking out the window every now and then. This thought occurred to me while staring at the GPS moving map display. I looked up just in time to see a high-wing Cessna at the same altitude approaching head-on at about a half–mile away. It did not take long to realize the situation required some corrective action. I punched off the autopilot, swung to the right, and watched as the other airplane passed to our left without altering course in the slightest.
Thinking we had now had our close call for the day, I started to relax when Center told me that we were back in radar contact. Not 15 minutes later, I was given a traffic advisory at the two o’clock position, same altitude, and southwest bound. I imagined this might be a converging situation, so I kept looking for the traffic. Sure enough, shortly thereafter a dot appeared in the windshield at the two o’clock position and slowly grew larger. It became increasingly apparent that once again something would have to be done. Off came the autopilot, a descent was initiated, and we watched as another high-wing Cessna passed directly overhead without altering course in the slightest.
I have been flying small airplanes on and off for several decades. I have had close calls before. They tend to happen quickly. I had never had two close calls inside of 20 minutes before that particular Sunday. The FAA says that most midair collisions occur in VFR weather during weekend daylight hours. That is exactly what we had going. It is very easy to get complacent in those conditions, and that is why midairs happen.
One could say that I should have been at 4500 feet MSL because I was VFR westbound. That would have theoretically eliminated the first threat, but not necessarily the second. Even if the moral of the story is to cruise higher than 3000 feet above the ground regardless of the wind, it is not always practical to do so.
There is another contributing factor besides complacency. An airplane on a collision course will appear to have no relative motion. This makes it very difficult to detect with the human eye. A moving target is much easier to spot, but a moving target is actually less of a collision threat. This link graphically illustrates how easy it is for your eyes to play tricks on you in this regard. Keep them moving when you are scanning for traffic!