Why can’t we just make the whole plane out of black box material?

386 views

Why can’t we just make the whole plane out of black box material?

In: Engineering

The black box material isn’t really anything special, it’s just designed to be Hardy. If they made the whole plane like that it the plane might survive, but everyone on board would still die from fire or blunt trauma. Humans can’t survive sudden stops from high speeds.

In addition, the hardening of the plane would make it much heavier causing much more thrust to get off the ground.

Flying is still one of the safest ways to travel as is.

The interstate isn’t wide enough.

The black box isn’t made of some incredibly tough material that we don’t otherwise use in aircraft. It’s just stainless steel and titanium, solidly braced and heavily constructed. If we built aircraft the same way crash landing would be nearly impossible, largely because the plane would be too heavy to fly and crashing it would require driving over the edge of a cliff.

With airplanes, it’s almost always about weight. Building the plane right and putting in the air is simple enough (given proper engineering and piloting). *Keeping* it there as efficiently as possible is the bugaboo. Ultimately, it’s the cost of fuel (which you need more of for more weight) — not to mention the added effort for the pilot keeping a behemoth (weight-wise, in this case) in the sky.

If the hull of the plane was made of super sturdy material, the passengers inside are not. The sudden deceleration would have all the passengers flung towards the front at fast speeds.

It’s the same reason cars are built less sturdy than vintage cars. They are designed to crumble so the deceleration isn’t as fast.

Force=mass*acceleration

You can’t decrease the mass, but if you decrease the negative acceleration (deceleration), you can reduce the force of impact

[removed]

The black box isn’t actually made out of anything particularly special – making something stronger often isn’t a particularly hard or complicated job, as a lot of the time it just comes down to making it thicker and more solid.

In the case of a black box type of object, if you make the walls thicker, and do things like bracing weak points (like corners) in the structure, you can make it survive almost anything.

The downside to this is that it means more weight – something that isn’t an issue if you are talking about something like a safe or piece of construction machinery where weight doesn’t matter, but in an aeroplane weight is critical – the heavier a plane is the harder it is to get it off the ground, and the more fuel it will use.

So each different component on a plane is made to suit its job – the black box needs to be solid, so they make it suitably strong, but also as small as possible so it doesn’t weigh too much, while components like the wings or body need to be much larger, so they design them using a much lighter construction to save as much weight as possible.

So we do actually use the materials a black box is made from elsewhere in planes, only we use much lighter versions of them. If we made the whole plane black box strength, it would be too heavy to fly.

Incidentally, black boxes aren’t actually black, but a nice bright shade of emergency orange – after all if there is an accident, you want them to be obvious and easy to find in the wreckage.

And as another side note in favour of air travel – it is commonly noted that you are more likely to die driving to the airport in a car accident than you are in a plane, so while accidents tend to make the news, in reality planes are very safe, and absolutely designed for purpose – making an air liner black box strong wouldn’t actually make them that much safer – most accidents are caused by other factors like pilot error, malicious intent, or other component failure (that won’t be stopped by making the wings bomb proof).