The most advanced bomber anyone had ever built lasted about thirty seconds in the air.
October 30, 1935, Wright Field, just outside Dayton, Ohio. Boeing had brought its Model 299 to the Army Air Corps bomber competition and everybody more or less knew how the morning was going to go, because the thing was enormous, it flew farther than anything else in the running, it carried more, and it had four engines at a time when the competition had two. A Seattle Times reporter walked around it, counted the gun positions bristling off the fuselage, called it a "flying fortress," and Boeing liked that enough to go copyright it.
Then it took off, climbed too steeply, stalled, and came down in a wreck bad enough to end the demonstration and very nearly end the program.
The cause was two small pieces of metal.
Big aircraft have gust locks — clamps that hold the control surfaces still while the plane is parked so the wind doesn't bang them around. You put them on when you park. You take them off before you fly. That morning nobody took them off, and the crew found out at roughly two hundred feet, which is not a great altitude for finding things out.
Everyone reached the obvious conclusion
Too complicated. Four engines, retractable landing gear, wing flaps, electric trim, constant-speed propellers, every one of them a thing you had to set correctly, in the right order, while also flying an airplane almost nobody on earth had meaningful time in.
The Army cut its order to thirteen and handed the real contract — 133 of them — to the Douglas B-18. Smaller, twin-engined, worse at very nearly everything, and apparently the amount of airplane a human being could be trusted with.
Boeing's engineers landed somewhere else
They didn't think it was too hard to fly. They thought it was too much to hold in your head.
Which is a far cheaper problem to have, since you fix "too hard to fly" with better pilots or a simpler airplane and you fix "too much to hold in your head" with a piece of paper.
So they made a list. Not a manual, not a training program — a short list of what had to happen before takeoff, on takeoff, before landing, and after landing, small enough to fit on an index card and boring enough that a cockpit full of people who already knew every item cold would read it out loud anyway, every single time, forever.
The pilot that morning was not some rookie who wandered in off the flight line. He ran flight testing at Wright Field. Whatever was missing, it wasn't skill, and no additional amount of skill was going to supply it.
The thirteen airplanes nobody wanted
Became the Y1B-17, which became the B-17, which became one of the most consequential aircraft of the Second World War, built by the thousands and flown by crews who ran a checklist before every flight because by then that was simply how you flew an airplane.
The habit spread out of those test pilots into all of military aviation, then commercial aviation, and eventually into operating rooms and construction sites and nuclear plants — anywhere the price of forgetting step four gets unreasonable.
October 30 is now National Checklist Day. We did not make that up, and we were probably more delighted to learn it than is normal.
Anyway
We're a to-do list app. We've spent more time with this story than most people would.
The tasks people drop are almost never the hard ones. They're the ones that quietly slid out of your head while you were busy doing something else — the renewal, the reply, the step you've done a hundred times and skipped exactly once, on the day it counted. Nobody has ever fixed that by trying harder.
What 1935 didn't solve, and what ninety years of checklists since haven't solved either, is that the index card has edges. Every list app built since has handed you an infinite sheet of paper and called that a feature, which is how you end up with a list growing faster than you can work it and a low hum of being behind in a race nobody told you you'd entered.
Your day is the paper. It's a specific size. It always was.
That's what we built — the first checklist that measures the sheet it's written on, sorts for what actually fits in the hours you've got, and then tells you when you're finished. Not finished for now. Finished.
A list is supposed to end. That's the entire idea of a list.
Sources: National Museum of the U.S. Air Force, This Day in Aviation, The Aviation Geek Club.