I mostly fly AS and AA - but when I do fly BA and CX, I notice the safety video talks about the brace position. (The CX video seems a little more dramatic on this.)

Now, it makes sense that on AS/AA flights we don't need to know about the brace position, because of __<insert your own humorous reason here>___... but it gets me thinking... what's the correct/proper brace position.

Using Google Image Search, I see a lot of different brace positions. Arms under your legs. Arms crossed resting on the seatback. Hands over your head and against the seatback. (But I know not to interlace - or you end up with broken fingers. Oh, and take off the ol' glasses.)

Which one is the best/most proper?

I think that the important thing about the brace position in a survivable crash landing is two-fold: to get your body down below the seat backs to protect your head and body from debris flying through the cabin during the deceleration and break-up following ground or water impact; and, to the maximum extent possible, keep the arms and legs from whiplashing around.

I would think that you are physically closer to the floor and could follow the emergency lighting easier if there was fire and smoke.

I remember an accident investigator telling me that the most frequent cause of death in most

survivable crashes is internal bleeding caused by the aorta ripping from the heart as a result of large G-forces resulting from the rapid deceleration. My hunch is that the aorta can withstand higher G's in the axial direction than in the radial direction. You would place those organs in the axial direction in the brace position.

About ten years ago I was on an AA Super 80 and shortly into the flight we were told that we would be making an emergency landing at RDU. The cabin crew was great. I was escorted from my bulkhead row economy seat toward the back. The FA explained that they were placing people close to the over the wing exits. She said I should take the brace position for landing and not raise my head to look out the window until told it was safe to do so. Fortunately there were not many pax on this flight.
I inquired about the brace position. I was told basically to place my head between my knees. I thought this would be easy. However, this was the first time I had placed my head between my own knees.
We made a normal landing at RDU and taxied to the gate. I still marvel at how calm and professional the crew performed. I saw no fear in the crew or any of the passengers.

The most common cause of death in aircraft accidents is smoke inhalation. After that it's blunt force trauma. Certain types of crashes will also produce high loading on the femur that can cause fractures and may interfere with exiting the aircraft.

In normal seating the best position is the "kiss your but good bye" aka head between your knees. If there is not enough space bend forward as far as possible and brace yourself against the seat ahead of you and cover the back of your neck. Always read your aircraft flight safety card for further instructions.

My friend was an Air Force accident investigator who strictly investigated USAF accidents and foreign accidents involving fighter aircraft we had sold to somebody. In these particular brand of accidents, fire was rarely the cause of death. Fighter aircraft, of course, have much smaller cabins and fresh air is a canopy jettison away. In a lot of his crashes, the primary cause was either a bad batch of fuel or they simply ran out of gas. Also, if you consider that a lot of pilots can simply punch out of military aircraft, especially ones on fire, this reduces the number of military aircrews who survive a crash where the airplane was on fire at impact. In a lot of his crashes, the airplane bounced first, which can cause a fire, and became airborne again for about a half mile or so. In this case, it's debatable whether or not the pilot was killed by the first, second, or third impact. They would often arrive at the crash site and walk in the direction of flight to find the first indication of impact -- usually broken tree tops or a scuff in the ground.

I definitely agree, for survivable commercial and general aviation crashes, that smoke inhalation is a more likely cause of death.

Huh, so those FTers who talk about carrying their own smoke hoods even on commercial flights weren't just bragging/joking....

There is of course anther brace position for use during a TSA search but perhaps that is a little off topic

The whole concept of a brace position is a total joke, given the seat pitch that most of us endure in Y. Heck, I can't even lean forward to tie my shoe laces, let alone place my head between my legs. It's a concept with no practical application to 80% of travelers (i.e. those not in C/F who have enough space to attempt this piece of gymnastics).