Developer's default setting created turbulence in the flight simulator

What is it? It's an instrument used to train pilots, but that's not important right now

who, me? Welcome once again, gentle reader, to another instalment of Who, Me? – the Monday missive in which Reg readers share stories of occasions on which their prowess didn't quite meet tech repair challenges.

This week, meet a reader we'll Regomize as "Shirley" whose very first job as a software developer was for a firm that built professional flight simulators for pilot training. You know the sort of thing: essentially the cockpit of an airplane, connected to computers to recreate conditions pilots might encounter during flight, surrounded by a screen outside the window so it looks real, and all mounted on an electro-pneumatic motion platform so that it feels real too.

These things are not cheap. The experience must be as much like flying a real aircraft as possible, so the parts they're made of are the real deal – from switches and levers down to the delicate electronics underneath it all. This is not an Xbox.

Or, as Shirley put it, "even the paperwork would set you back thousands."

The sim that Shirley worked on had been promised to a client for $16 million. And Shirley was one of 30 developers working on it, so it was in use pretty much around the clock, with limited time to test things out.

(Shirley recounted a separate incident in which a dev was working on a simulator and accidentally shut the power down when he was alone in the lab at 3:00 AM, so he had to climb out the emergency escape hatch and down a rope ladder in the dark. Guess that guy picked the wrong week to give up … whatever.)

Anyway, deadlines and testing schedules led to a fairly chaotic atmosphere on Shirley's project.

The bit he was working on had to do with the vibration system (remember that electro-pneumatic platform?) to make it feel like the trainee pilots were really up in the air, experiencing real things that happen in flight – you know, like, say, extreme turbulence. Sitting in the cockpit with his laptop, Shirley implemented a "nifty little slider control" that would adjust how much the cockpit shook – from zero to 100 percent. That last setting probably not something you want to encounter on a real flight.

Having finished his coding, Shirley went to test his changes. And when he switched it on, he realized to his horror that he had neglected to consider what the default setting should be.

The simulator – or whatever gods of mischief were in charge at that moment – therefore decided the default should be set to 100 percent, a condition that felt more like a plane hitting a mountain than a plane in flight.

At that level, the $16 million worth of delicate machinery began trying to destroy itself, not to mention the young software developer inside – who was learning how it feels inside a cocktail shaker.

Somehow, despite his skeleton and his brains being jangled violently in opposite directions, Shirley found sufficient coordination to adjust the slider on his laptop down to a more survivable level.

Thankfully there was no damage to either the machine or Shirley – but he didn't mention the incident to the boss.

If you've ever made a small error that nearly led to the destruction of millions of dollars worth of equipment, you're not alone. Tell us about it in an email to Who, Me? and we'll share it with other readers.

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