Why do they say “brace for impact” when a plane crashes, if bracing is what kills you in car accidents?

Question

I have heard that if you tense or brace your body before a car accident you are more likely to be injured. Hence why drunk drivers often walk away unharmed because they just sort of flop around instead. So why is it that we are supposed to brace for impact?

In: 3739

Answer 1

I took an aerospace standards and certifications course for engineers, where we covered this sort of thing.

The top comment is pretty spot on but is missing the most important thing.

Basically a lot of deaths or permanent injury from a hard landing come from secondary trauma. Either from hitting your head twice due to whiplash or getting hit in the head from unsecured items. Two concussions, one after another are really really bad.

On top of that bracing secures your head and upper body so you don’t have whiplash which can be debilitating in the long term and can prevent you from leaving the aircraft under your own power in the short term.

Lastly, in a car accident you do not have time to brace. Second if you are in the front seat then bracing in the front seat will kill you because placing your head against the steering wheel or dash will cause your head to move into a position that is incompatible with life once the airbag deploys.

Imo for rear passengers bracing is probably effective but because car crashes happen suddenly, it is basically impossible.

Also i am pretty sure this idea that drunk drivers survive car accidents because they are unable to brace is false (i seem to recall reading some expert analysis that confirms this). It does not make sense from an engineering perspective. If it did we would design car safety systems around the idea of having the body be flexible during a crash. But in fact we do the opposite. We have seat belts and head rests to prevent as much movement as possible.

Imo it is most likely that drunk drivers by virtue of being the one to cause an accident have a larger opportunity to maneuver the vehicle so that they are less likely to be killed. To quote Dwight Shrute “In the event of a crash the driver always protects his side first”.