Safety Spotlight: No easy answers
Why did an experienced pilot err so greatly?
Meanwhile, Thunderbird 5, the lead solo pilot, performed his aileron roll on takeoff and Thunderbird 6, the opposing solo, began a maximum-performance afterburner takeoff, to be followed by a split-S maneuver down the showline—which runs parallel to and 1,500 feet in front of the crowd line. Floating the sweeping left turn back inbound, gathering speed, and with about 45 degrees remaining to face show center, I heard Thunderbird 5’s frantic voice call “knock it off,” the universal aviation call to cease all maneuvering because of a dangerous situation. I echoed the knock-it-off call, continued the turn perpendicular to the show line, and faced a horrifying sight. Along the show line, parallel to and directly in front of the crowd, was a line of fire a couple of thousand feet long.
A linear crash line is a more fearsome sight to low-altitude pilots than a single, smoking-hole impact. A linear crash line usually means the pilot stayed with the airplane and didn’t get out. My heart sank. The fear turned quickly to sorrow and deep grief at what was certainly the loss of a beloved pilot. I knew his beautiful family well, and his two young children immediately crossed my mind. What grief they soon would know.
I led the diamond formation over show center, crossed the line of fire, and began a turn to orbit the crash site, when one of the Thunderbirds made a call that remains the most emotional radio call I’m likely to ever hear. “Thunderbird 6 is standing, and waving at the crowd.”
Ejecting less than a second before impact, well outside the ejection window and without time for a full parachute deployment, Thunderbird 6 hit the soft Idaho “moon dust” on a linear vector, directly in front of the crowd, and tumbled to a stop with barely a scratch.
An Air Force investigation team found that Thunderbird 6 miscalculated his altitude above the ground and began the split-S maneuver some 800 feet below his target apex altitude. The more difficult question, which vexed the accident board, was: Why did an experienced and disciplined pilot commit such a large miscalculation?
The investigators combed through hours of tape from previous airshows and maneuvers. They found remarkable discipline and consistency in Thunderbird 6. He never hedged his parameters and performed the split-S maneuver with consistency in his apex altitudes and speeds. The investigators settled on three factors that led to the critical error, the most intriguing of which was what they called a “preconscious level of awareness.”
In essence, the investigators noted several indirect influences that may have established a predisposition toward subconscious error:
- High density altitude, which reduced aircraft performance and lengthened the time it took to climb to the minimum altitude required to begin the split-S. In Thunderbird 6’s internal clock, it likely felt about the right time to roll inverted and pull, and when he checked his altimeter, he saw what he expected, not what was displayed.
- Comments I had made as leader in the preflight briefing about this show at 3,000 feet msl feeling more like our home field—Nellis Air Force Base in Las Vegas, Nevada, at 2,000 feet msl—than our previous day’s show in Reno, at 5,000 feet msl, may have influenced the altitude numbers in 6’s subconscious.
- The egregious requirement for Thunderbird pilots to perform mental calculations on exact agl altitudes. While inverted in a split-S maneuver, Thunderbird 6’s focus on the math likely distracted from his focus and contributed to him misreading the conspicuous altimeter read-out.
- Fatigue, mentioned as likely, since the team was on the home stretch of a long show season that began in March.
The investigators struggled to explain why a talented and disciplined pilot made such an error on a maneuver he’d performed hundreds of times with an impressive degree of consistency. There was no smoking gun. Somehow, it seems, a lot of little things added up and in the flash of a moment, a near-fatal mistake was made.
One of the many lessons from that September day is how quickly aviation can turn from routine to disastrous. Our subconscious is constantly working: assessing, calculating, making decisions, usually in our favor. But it is imperfect, and when the stakes are high, we need redundant methods to confirm decisions with critical implications. Such decisions are made every time we fly.
Go fly. Keep an eye on the influences to your subconscious, and the resulting actions, which could drastically change the outcome of your flight.
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