Hacker News Reader

Comment by Cyberdog | Hacker News Reader

Reading articles and seeing videos about airline disasters tends to increase my faith in flying rather than making me more afraid of it. Terrorism or sabotage aside, so many failures have to compound to put a modern airliner in a truly irrecoverable state that it's effectively impossible to happen and not worth my time to even worry about. What times we live in that we can hurtle ourselves across oceans at hundreds of miles per hour and be in substantially no more danger than we would be walking down a sidewalk in our home town (in before HN commenters reply with information about all the dangers associated with sidewalks).

View on HN

That assumes the environment the aircraft flies in, behaves predictable. Sometimes it does not.

Turbulence is an obvious one. Downdrafts another. You can have a perfectly functional aircraft, but if the whole air column it's in goes down faster than the aircraft can climb, the aircraft will go down with the air column no matter what.

Reminds me of an Air Crash Investigation episode: some volcano had erupted, ash was high up in the air, air traffic control wasn't aware of this, and iirc it didn't show up on weather radar or similar systems (or on the planes' systems).

So it looked all clear. Meanwhile the whole plane was getting ash-blasted. To the point that paint was stripped, cockpit windows went from clear to matte, and ash attached itself to engine fan blades. Obviously trouble followed...

Bottom line: the environment a vehicle moves through, is always a factor. Sometimes an unpredictable, uncontrollable and/or hazardous one.

I'm not familiar with the volcano incident you referred to, but a bit of searching seems to indicate it was British Airways Flight 009 in 1982, where a 747-200 had all four engines fail due to volcanic ash… then glided safely out of the ash cloud and was able to restart three of the engines and land safely at a major airport. From a complete loss of power to all engines to on the ground with zero deaths, zero injuries. That's exactly the kind of story I'm talking about that gives me such faith in flying!

Sounds like the one! Engine after engine going out. Without (at first) any obvious cause.

> From a complete loss of power to all engines to on the ground with zero deaths, zero injuries. That's exactly the kind of story I'm talking about that gives me such faith in flying!

Understood (and agreed). But you missed my point: fate of that flight didn't result from safety engineering. It depended entirely upon the ash-laden air it flew into, and its effect on the aircraft & its engines. No amount of systems redundancy could have made it a safe flight.

So yes: flying is very safe these days. But there are limits to what safety engineering can provide.

> No amount of systems redundancy could have made it a safe flight.

But it did! One obvious example being the redundancy that allowed the plane to fly safely despite one of the engines not restarting.

The plane encountered an entirely unpredicted situation that caused damage, but thanks to its design was still able to land safely.

They got lucky because when they descended after the engines died, the engine cooling caused small physical size changes and the caked/burned ash just fell off the rotor bits allowing the engine to work again.

To RetroTechie’s point, they got lucky. No design decision saved them. Without that they’d have been a glider until they hit 0ft and it likely would have been far worse.

We’ve clearly gotten very good at flying, managing most weather conditions we’re likely to fly through, the mechanics/maintenance of the planes, and pilot training.

I’ve gained a ton of appreciation for how detailed our preparations are from watching Air Disasters. But we just can’t control everything, some danger is inherent.

Today we have VA monitoring satellites and aircraft aren't routed through VA.

That flight is why, IIRC.

I was a nervous flyer until I worked on the Boeing 757 design and found out how all the redundancy, etc., worked.

I was a nervous flyer until I piloted a 737 completely from power off to takeoff. I did the exact moves that I HATED as a passenger. Turns out you can’t control the wind and ATC transmissions eat into your mental capacity sometimes leaving you “behind the ball”. The result was a take off flying above speed causing the auto throttle to reduce engine speed greatly (the feeling as though the pilot turned off the engine in mid climb), turning to match ATC requested heading and banking a little bit more than expected passenger comfort, and finally reducing flaps without banking or otherwise reducing AoA giving that weightlessness rollercoaster feeling during the climb. All of this in a span of 5 minutes.

Once I got into our regular flight profile and following our flight plan, I just sat back in my seat and let out a hysterical laughter. I am the calmest person when I fly now :)

And that's how software should be written too..

Reply on news.ycombinator.com