failsafe

3 Articles

Radio Apocalypse: The BBC Radio Program That Could(n’t) Have Started WWIII

September 21, 2023 by 28 Comments

Here’s a question for you: if you’re the commander of a submarine full of nuclear missiles, how can you be sure what not receiving a launch order really means? If could — and probably does — mean that everything is hunky dory on land, and there’s no need to pull the trigger. Or, could radio silence mean that the party already kicked off, and there’s nobody left to give the order to retaliate? What do you do then?

One popular rumor — or “rumour,” given the context — in the UK holds that BBC Radio 4, or the lack thereof, is sort of a “deadman’s switch” for the Royal Navy’s ballistic missile subs. [Lewis (M3HHY)], aka Ringway Manchester on YouTube, addresses this in the video below, and spoiler alert: it’s probably not true.

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Safety Systems For Stopping An Uncontrolled Drone Crash

August 15, 2019 by 33 Comments

We spend a lot of time here at Hackaday talking about drone incidents and today we’re looking into the hazard of operating in areas where people are present. Accidents happen, and a whether it’s a catastrophic failure or just a dead battery pack, the chance of a multi-rotor aircraft crashing down onto people below is a real and persistent hazard. For amateur fliers, operating over crowds of people is simply banned, but there are cases where professionally-piloted dones are flying near crowds of people and other safety measures need to be considered.

We saw a skier narrowly missed by a falling camera drone in 2015, and a couple weeks back there was news of a postal drone trial in Switzerland being halted after a parachute system failed. When a multirotor somehow fails while in flight it represents a multi-kilogram flying weapon widow-maker equipped with spinning blades, how does it make it to the ground in as safe a manner as possible? Does it fall in uncontrolled flight, or does it activate a failsafe technology and retain some form of control as it descends?

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AirAsia Crash Analysis: Who Or What Failed?

December 4, 2015 by 108 Comments

Just a few days after Christmas last year AirAsia Flight 8051 traveling to Singapore tragically plummeted into the sea. Indonesia completed its investigation of the crash and just released the final report. Media coverage, especially in Asia is big. The stories are headlined by pilot error but,as technologists, there are lessons to be learned deeper in the report.

The Airbus A320 is a fly-by-wire system meaning there are no mechanical linkages between the pilots and the control surfaces. Everything is electronic and most of a flight is under automatic control. Unfortunately, this also means pilots don’t spend much time actually flying a plane, possibly less than a minute, according to one report.

Here’s the scenario laid out by the Indonesian report: A rudder travel limit computer system alarmed four times. The pilots cleared the alarms following normal procedures. After the fifth alarm, the plane rolled beyond 45 degrees, climbed rapidly, stalled, and fell.

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