6 Small Math Errors That Caused Huge Disasters

If there are any children reading this, there's really only one thing we want to tell you about adulthood: If you make one tiny mistake, people will die.

Don't believe us? Let us share these tales of completely forgivable design mistakes that cost lives.

#6. An Airliner Crashes Due to Square Windows


In the 1950s, companies were making the first foray into jetliners, and leading the pack was the de Havilland Comet. It was a state-of-the-art jet with many never-before-seen features, such as a pressurized cabin that allowed it to fly higher and faster than other aircraft.

Unfortunately, in 1954, two Comets disintegrated midflight for no apparent reason, killing 56 people total. In retrospect, the name "Comet" was a bad choice.

Although it was superior to de Havilland's first choice, the "Murder Bird."

The Laughably Simple Flaw:

It had square windows.

This is one of those things that is easy to miss (the designers missed it, for instance) but easy to understand once it's explained.

Here's a Kit Kat style candy bar. Where would you say this thing is most likely to break when pressure is applied?

Along the willpower line, probably.

Right there at those sharp notches, obviously. That's why they're there, and it's why no one builds important structures out of Kit Kats.

Well, a square window is made up of four 90-degree notches cut out of your wall, creating four of these weak points. You don't need a diagram -- if you have brick or stucco on your house, go outside and look. You'll find cracks there, protruding right from one of those sharp corners:

To fix, place head in bucket of sand and hum loudly.

In engineering, that sharp corner (or groove in the Kit Kat) is called a "stress concentration," a spot where the shape of the object makes it more likely to break under stress.

You don't want the red bit.

So if you're an airplane maker, how the hell do you fix that?

Well, have you ever noticed how on every plane you've ever been on, the windows you look out of have rounded corners? Those curves are pretty much the only thing keeping the plane from tearing itself apart in midair like in that scene from Fight Club. It distributes the stress to all of the various points along the rounded curve, rather than on that one sharp corner, which otherwise would (as they found out) tend to pull apart and form a crack over time.

Trust us, this was not easy to figure out. Experts had no idea why the planes weren't holding together until they tested the structure by simulating the repeated pressurization of the cabin. Sure enough, the fuselage eventually burst like a bootleg condom, and the break started with cracks right at those window corners.

Getty / plane-crazy
Top: Safe and enjoyable ride. Bottom: Explosive Caesarean section.

Representatives from competing companies Boeing and Douglas both said that their engineers hadn't thought of it either, and that if the Comet hadn't been first, it would have been one of theirs that crashed. Planes have had windows with rounded corners ever since.

#5. Fighter Jets Crashed Because of the Angle of the Runway


You don't have to be a pilot to guess that landing on an aircraft carrier is really fucking hard. It's a tiny little landing strip crowded with other planes, bobbing up and down in the waves. Keep in mind, this is with a whole host of instruments, computers and signals to help guide planes in. The early planes didn't even have that.

But there was another problem ...

The Laughably Simple Flaw:

Here's what the earlier carriers looked like. Couldn't be simpler, right?


It's a floating runway. How else would you design it?

Well, that design was kind of a suicide factory. As you can see, planes waiting to take off sit at the other end of the runway you're trying to land on. If you don't get stopped in time, you're going to create one hell of a fireball. And getting stopped in time was no small thing -- catching the arresting wire (the thing that stopped the plane) was a tricky business. Eventually carriers went with the cartoon-logic solution and installed barrier nets to stop planes if they missed all the wires. However, it wasn't all that uncommon for aircraft to bounce over the barrier.

Like skipping stones over a pond, if the pond had sharks and you had no arms.

So what was the brilliant innovation that allowed them to make landings that much safer?

They angled the landing strip about nine degrees.

And as the Navy learned from trailer parks, double-wide is always better.

Don't laugh -- it took years to come up with it. While some of the greatest technological advances in history, including space flight and splitting the goddamn atom, came from developments during World War II, we didn't think of angling the flight deck until 1952. Prior to that, every landing was a potential rear-end collision.

By angling the deck, a plane that missed the wires could go to full throttle, take off again and come around for another pass. Planes waiting to take off are near the bow, out of harm's way.

See? Absolutely no planes in the way.

Angling the deck also allowed for the tactical advantage of being able to launch and recover aircraft simultaneously, whereas in WWII, launching had to be postponed while landings were occurring, and vice versa. Who knows how many lives could have been saved if someone had thought of doing this about 10 years sooner.

#4. A Huge Walkway Collapses Due to a (Seemingly) Inconsequential Design Change


When designing their newest hotel to be built in downtown Kansas City, the fine people at Hyatt Regency wanted all the bells and whistles in it. The architectural firm in charge of the building design came up with a series of aerial walkways suspended from the ceiling so that guests could people-watch from a heightened vantage point. All in all, it was a pretty nifty feature. Until it suddenly collapsed and killed more than a hundred people.

"We can claim these were either terrible walkways or aggressively efficient elevators."

The Laughably Simple Flaw:

One long rod was replaced with two short ones.

If there's one principle consistent across all human nature, it's that we will always prefer the path of least resistance (i.e., "if you can get away with a half-assed job, do it"). The original plan was for two walkways that were directly on top of one another to both be supported by one very long rod that would anchor into the ceiling. Like so:

This is a highly technical diagram.

Looks pretty simple, right? It all hangs off one long rod, which makes it strong, but also makes it a pain in the ass to assemble -- the rod has to extend through both walkways and then alllll the way up into the ceiling. Just in general, big pieces are hard to work with -- what's easier, to carry a whole assembled desk into your house, or a series of small pieces? The rod also has to be threaded all the way along its length so you could screw that nut up to that top platform spot.

Got to be an easier way, right? So, the steel company in charge of making the rods made a design change by replacing the single rod with two shorter ones, shown below.

The guy with the hat is Rodney, a multimillion-dollar investor. The other is Nutter.

Easier to work with, easier to install, works exactly the same. Right?

That little change killed 114 people, injured 216 more and cost $140 million in lawsuits.

Look at the first image again.

Nutter has an idea for an FTL drive, but also a tool that injects bacon with peanut butter.

One rod, two nuts. Each nut only has to carry the weight of its own platform. Which is good, because each nut (and the welded beam it's screwed to) is only rated to carry the weight of one platform.

Now look at the second image. See the nut we've labeled "OH SHIT"?

The twain shall never meet, and civilization is hollower for it.

That one single nut now has to carry the weight of BOTH platforms, and all the doomed tourists standing on them. Look obvious? Congratulations, because none of the professionals at either company caught it.

And so, one night during a dance competition, the stressed "OH SHIT" nut cleaved clean through the beam and the walkways collapsed.

Considering this was 1981 and something called a tea dance, we're willing to rule it a suicide on the part of the building.

During the ensuing lawsuits, it came out that neither the steel company nor the engineering firm in charge of construction had even bothered to do a back-of-the-envelope calculation that would have shown them this glaring flaw.

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