There I was in a left echelon trailing position in a close formation of two KR-2’s with my hangar partner, Dick Osterhof. It was a typical Sunday morning flight from DeQuincy, Louisiana (5R8), with visual meteorological conditions and Gulf Coast haze. We were not going anywhere in particular, just staying close to our home base at about 3,000 feet. Dick was leading our flight path and navigating, while I spent 99 percent of my time looking at him, keeping about 20 feet of clear space between us.
While keeping an eagle eye on Dick’s KR-2, I noticed a tiny black speck show up about an inch or two above his half-bubble canopy. The speck eventually sprouted a fuselage, twin-engine nacelles and a T-tail. By the time the wing panels outboard of the engines became big enough to see, along with the turbine exhaust pipe exiting the near side nacelle, I was measuring four G’s on my panel accelerometer and depressing my control stick microphone switch, saying with urgency, “DICK, PULL UP”!
I estimated that only about five seconds passed from the first moment of the dot being visible over Dick’s canopy until flight path intersection. The dot blossomed into what could only be a Beechcraft Super King Air. Our 140 mph airspeed, plus the King Air’s capability of 350 mph added up to a potential 500 mph closing velocity. (A King Air pilot obeying Federal Aviation Regulation Part 91, Section 91.117a, would have been flying no more than 288 mph below 10,000 feet MSL—a trivial distinction.)
By pulling up so abruptly, Dick’s KR-2 disappeared below my instrument panel. His invisibility inspired my choice to go straight up, knowing that I had begun my evasion maneuver at least a couple of seconds before he could begin anything like my own pull up.
Having asked Dick to “pull up,” I anticipated that he was likely coming up where the floor of my KR-2 under my rudder pedals was blocking my view of his flight path. Therefore, pushing my stick forward to recover towards his assumed vertical trajectory seemed like a losing idea. Having just missed a King Air, I did not want to run into a KR-2.
Pulling the stick back to reverse course before my airspeed sagged below 50 mph was my guaranteed safe path away from Dick and back the way I’d come. By the time I was upside down heading away from him, I was sure I did not want to complete a loop headed back in Dick’s general direction. Rather than take a chance on a loop completing a path back towards running into him, I rolled halfway around to right-side-up, let the nose drop, and leveled out after my first ever Immelmann.
Once I was settled in level flight headed safety away from Dick, I radioed him to see where he was. There would be no sense in turning back together until we both knew exactly where to find the other. After being separated by almost a mile, we finally found each other for the return flight back to our hangar at DeQuincy.
Dick eventually explained later that at my call to “pull up,” he delayed taking action long enough to visually acquire the King Air for himself. Not knowing where I’d gone, he decided against following me up in the world’s loosest unplanned vertical formation. He chose to dive away from the King Air, thereby automatically accelerating away from me in a way I could never overtake even if I tried to hit him. Both being engineers, we’d each manipulated potential and kinetic energy in a way that was guaranteed to keep us apart, no matter what the other pilot might do, for at least several minutes after missing a three-aircraft midair collision.
Dick estimated later that the King Air passed about 15 feet directly over his canopy. The King Air was close enough to see its rivets, along with its pilot’s aviator sunglasses. The clearly visible pilot’s facial expression was one of stoically blissful ignorance, lacking any clue that he’d detected the grave danger he’d shared with the two of us. His lack of any facial recognition of his mortal peril, along with the total absence of any observable deviation from his straight-and-level flight path, convinced Dick that the King Air pilot never saw us.
Reflecting back on the flight geometry in Figure 1, we realized that if the King Air had been coming from the left, as shown with the red position in Figure 1, instead of from the right, as it actually was in the blue position, then my left echelon trailing position, with eyeballs 99% looking ahead to the right directly at Dick, would have made it nearly impossible for me to detect the King Air during the five seconds it might have been visible on the left side until too late. I would have been looking in the wrong direction, to the right. The “high definition” fovea of the average eyeball retina can only perceive fine detail in about a 10 degree angle. Alternatively, if I had been flying in a right echelon trailing position, my 99% visual duty cycle looking ahead to the left at Dick would have made it nearly impossible to detect the King Air coming from the front right until too late, as with the blue outlines in Figure 1.
Meanwhile, Dick, being the leader of our flight of two, was operationally expected to aviate, navigate, communicate, and look for traffic coming from the forward arc of our flight trajectory. After all, my Job One was to not run into him, requiring that I watch him almost all the time.
Imagine flight leader Dick looking outside for traffic scanning from one side to the other in 10-degree foveal arcs for about one to two seconds in each high definition arc as required for the eye-brain electro-chemical system to actually detect and perceive a collision threat. A 180-degree forward scan for collision threat traffic would then require 18 views of at least one second each. A hypothetical two-second scan at the flight instruments between every outside scan of 18 seconds would then add up to about 20 seconds for the scan cycle.
So what happens to the probability of a pilot detecting a collision threat if a threatening aircraft is only visible for five seconds of a 20-second visual scan cycle, as it was in our Figure 1 Louisiana scenario? To a first approximation, five seconds divided by 20 seconds gives a one-in-four probability of even looking in the correct direction to detect the threat before two aircraft colide. Then 15 seconds of the 20-second visual scan cycle has the threatened pilot looking in the wrong direction 75 percent of the time, with no chance of detecting and evading the collision threat. Never mind that detecting the threat in the tail end of five-seconds of perceivable, detectable visibility may still leave too little time to late to even begin an effective collision threat evasion maneuver.
I learned two unforgettable lessons about aviation safety probability physics from this encounter.
(1) Flying at cardinal altitudes (1000, 2000, 3000, 4000, …), where others are liable to also be flying at the same cardinal altitudes, maximizes the danger of a midair collision. Following the crowd into accurate flight at cardinal altitudes is a losing bet that wastes the far safer random altitudes in between cardinal altitudes.
(2) It is impossible for any pilot to visually scan outside the cockpit with enough diligence to guarantee a safe landing any time where closing path traffic is visible even one second shorter than the length of time between the beginnings of a first and second visual scanning pattern looking for collision threat aircraft. The limitations of the fovea and the eyeball-brain blindness outside the foveal high definition arc guarantee that the National Transportation Safety Board will forever be using accident analyses with copy-and-paste boilerplate about the “the inherent limitations of the see-and-avoid concept” for detecting and avoiding collision threats.
This near midair collision inspired my 1997 peer-reviewed, published analysis supporting the above two lessons learned at:
My 2018 Experimental Aircraft Association (EAA) webinar convincing a supermajority of 89 percent of voting pilots of the above two lessons is available for viewing by current EAA members at:
My 2023 Colorado Pilots Association webinar updating my 2018 EAA webinar is available at