"Gear-Up" for Human-Centered Design and Safety Differently

Updated: Nov 15, 2019

F-14 after a Gear-Up Landing at Fentress. Pilot earns a call-sign: GULF

In modern-day aviation, joining the dreaded “gear-up” club is rare thanks to advances in design and an understanding that humans are fallible.

But it happens.

However, during the Second World War, gear-up club membership was at an all-time high as “error-prone” pilots would mistakenly raise the gear lever vice the flaps on landing roll-out.

B-17, Dutchess' Daughter, after a belly landing. (July 6, 1944)

In the cockpits of B-17s and other WWII aircraft, nearly identical controls for the flaps and landing gear were positioned next to each other. So, what’s the problem, you ask? For those of you who have not been in a cockpit, think about a typical kitchen stove and the placement of the four identical dials that control its four burners. Hold that thought.

On landing rollout, the B-17 landing checklist called for “Flaps Up” and the co-pilot or pilot would reach over and lift one of the two nearly identical levers. Early during the war, highly trained pilots would confuse the gear lever for the flap lever and, as a result, the landing gear would retract causing the B-17 to collapse and skid down the runway.

Identical stove knobs positioned next to each other.

Now, think back to the time(s) you turned on the wrong burner on your stove.

Are you to blame? Do you need better training to use your stove?

Was pilot error the cause of these B-17 “gear-up” landings?


Pilot error was a symptom or outcome of poor design. Better pilot training did not fix the gear up landing problem. Better system design did.

Gear-Up Landings: The Birth of Human-Centered Design & Safety Differently?

Alphonse Chapanis, a PhD from Yale and commissioned by the U.S. Army Air Corps to investigate the high number of B-17 "gear-up" landings, moved beyond pilot error to see that these “gear-up” landings were a result of context and poor system design.

Considered the father of Human Factors (Ergonomics)—a “discipline concerned with the understanding of interactions among humans and other elements of a system”—Dr. Chapanis' solution to the large number of B-17 "gear-up" landings involved placing a rubber-tired wheel on the landing gear lever and a wedge-shape end to the flap lever. “Gear-up” landings nearly disappeared overnight as a result of this intuitive design.

Accident investigations that stop at “human error” are not just bad but dangerous. Human error should, instead, be the start of the investigation. - Accelerate: The science behind DevOps

As you can see from this B-17 story, solving for the limits and capabilities of human performance is not new. But as the world becomes more complex and tightly coupled, putting the human at the center of design and learning to move beyond "human error" are organizational imperatives.

Human-Centered Design and Safety Differently: Opposites Sides of The Same Coin

Human-Centered Design (HCD)

According to the International Organization for Standardization, "Human-centered design is an approach to interactive systems development that aims to make systems usable and useful by focusing on the users, their needs and requirements, and by applying human factors/ergonomics, and usability knowledge and techniques. This approach enhances effectiveness and efficiency, improves human well-being, user satisfaction, accessibility and sustainability; and counteracts possible adverse effects of use on human health, safety and performance."

Safety Differently

Just as HCD develops features shaped around human needs and ergonomics, Safety Differently views human error as a consequence of a feature, not a cause. Safety Differently, a term coined by Sidney Dekker, provides us a new way to think about safety through improving systems, processes, planning and operations around the worker—putting the human at the center of design.

Principles of Safety Differently:

  • Workers are not the problem—we ask them what they need to do their jobs productively, safely, and reliably.

  • Safety is not defined by the absence of of accidents but by the presence of capacity

  • Safety ensures good things happen while workers work in complex environments—we need to move away from linear cause-effect explanations

  • Safety is an ethical responsibility down, not an upward bureaucratic approach

Although the language and context may differ, Human-Centered Design and Safety Differently are opposite sides of the same coin stamped more than 70 years ago by a Yale PhD.

Brian “Ponch” Rivera is a recovering naval aviator, founder of AGLX, and the creator of the ZONEFIVE™ Team Performance Indicator. Contact Brian at brian@aglx.consulting.


Lavietes, S. (2002). Alphonse Chapanis Dies at 85; Was a Founder of Ergonomics. New York Times.

Forsgren, N., Humble, J., & Kim, G. (2018). Accelerate: The science behind DevOps: Building and scaling high performing technology organizations.

Safety differently: Human factors for a new era: 2nd ed. (2014). Boca Raton, FL: CRC Press.


B-17 from nationalmuseum.af.mil

Stove: My Stove, My iPhone

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