Despite all that, the climb continued — Page 326, Lesson 533

I want to walk you through a real accident sequence that illustrates how human performance limitations—things like stress, distraction, incapacitation, and poor decision-making—can cascade into a catastrophic outcome. This is the story of a Trident aircraft, and I'll take it step by step so you understand exactly what happened and why it matters for you as a professional pilot. We begin with two crew members: one described as having a "specific demeanour as a result of this outburst" and the other, Keighly, who had a "quiet, retiring nature" and a "general lack of confidence." Because of that personality dynamic, Keighly was "disinclined to mention" something—he didn't speak up. Meanwhile, the other pilot, Key, may have been "distracted by his chest pains." Already we have two human factors at play: a power gradient in the cockpit that suppressed communication, and a possible medical distraction. Despite all that, the climb continued. Now, for reasons that will never be fully established, around this time the "droop lever was operated, retracting them." The droops are high-lift devices on the leading edge of the wing—they increase lift at low speeds, especially during takeoff and climb. Retracting them reduces lift. It was likely Keighley who did this because the droop lever was on his side of the cockpit. Two theories exist for why this happened. One: the "stick push warning light" illuminated, and the crew mistook it for the "droop out of position" light—a classic confusion between two different warnings. Two: Key was so distracted by his chest pains that he associated the low airspeed with flap drag, and either retracted what he thought were the flaps himself, or asked Keighley to do it. Either way, the droops were retracted while the aircraft was flying at only about "162 kt"—knots. That's a low speed for a clean-wing configuration on a Trident. The aircraft then "entered the stall regime." Let me define what that means: a stall occurs when the wing exceeds its critical angle of attack, causing a rapid loss of lift. At 162 knots with the droops retracted, the wing could no longer produce enough lift to support the aircraft. Shortly after the droops retracted, the "stall warning" went off, and the "stick push system" operated. The stick push system is an automatic safety device that pushes the control column forward—nose down—to reduce the angle of attack and regain flying speed. This action would have automatically "disconnected the autopilot" and triggered a whole series of warnings in the cockpit: the stall warning, autopilot disconnect, master warning, and the stick push operating. So the cockpit became a cacophony of alerts. Around this point, Key had another, larger heart attack—his "heart muscle actually separated due to the blood pressure in a ruptured arteriole." He may not have been fully incapacitated, but he would certainly have been in great pain. So now we have a pilot with a serious medical event in the middle of an emergency. As the nose dropped due to the stick push, one of the pilots "pulled back on the column in an attempt to hold the aircraft level." That's a critical error: the stick push was trying to recover from the stall by lowering the nose, but the pilot fought it. The aircraft stabilized at around "177 kt" in a slight descent. No attempt was made to redeploy either the flaps or the droops—the high-lift devices that could have helped recover lift. Instead, the climb was reinitiated by pulling back on the column. The stall warning and stick push operated for a second time. Again, the crew attempted to hold the aircraft level instead of diving the aircraft, applying power, and deploying the high-lift devices. They repeated the same incorrect response. The third time the stick push system operated, it was "overridden by dumping the pressure in the system." The crew may have thought the stick push was faulty because of the previous warnings. It's likely Key did this, as the override was on his side of the centre pedestal. So now the automatic stall recovery system was disabled. By now, airspeed had increased to around "193 kt" as a result of being in a shallow dive, but for some reason the aircraft was reestablished back into the climb once again. Airspeed decayed to about "175 kt," and it entered the stall. Shortly after, the aircraft adopted a "60° nose-up attitude"—the Trident was prone to doing this in these circumstances. That extreme nose-up pitch led to the aircraft entering a "deep stall." Let me define a deep stall: it's a stall condition from which recovery is impossible using normal aerodynamic controls, because the airflow over the tail surfaces is disrupted and the elevators become ineffective. The aircraft's altitude at this point was "1275 feet (AGL)"—that's Above Ground Level, meaning height above the terrain. It was travelling at no more than "54" knots. From a deep stall at that low altitude, there was no recovery. So what does this teach us? Multiple human factors combined: a medical incapacitation, a cockpit authority gradient that prevented challenge, distraction, misidentification of warnings, incorrect manual override of a safety system, and repeated failure to apply the correct stall recovery procedure—dive, apply power, deploy high-lift devices. Every one of those is a limitation you must learn to recognise and avoid in your own flying.