That Didn't Suck
The top of a Southwest Airlines passenger jet popped open at 36,000 feet, but no one was blown out through the hole. Why not?
A Southwest airplaneA five-square-foot hole opened in the roof of a Southwest Airlines jet as it was cruising at 36,000 feet on Friday afternoon. Passengers reported hearing an explosive noise and feeling "air being sucked out" of the cabin, but the pilot was able to land the plane safely and there were no major injuries. Why wasn't anyone blown through the hole?
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How risky might the latest incident have been for passengers? The pressure differential between the cabin and the outside was approximately 7.5 pounds per square inch, and the hole measured 720 square inches. That means the maximum force applied would have been around 5,400 pounds—more than enough to blow an unrestrained person out of the plane. But a passenger would only feel that much force if he were literally plugging the hole
Keep in mind that the hole was not right next to any passengers or beneath their legs. It was in the ceiling of the cabin, which would have been at least two to three feet away from the heads of anyone sitting inside. At that distance, the force of an explosive decompression would be greatly dissipated. Air-flow patterns are complicated, and it's impossible to quantify this effect for any given passenger. But as a simple way to visualize the effect of distance, we might imagine the force spreading itself out across the surface of an expanding hemisphere centered on the hole. Using the formula for spherical surface area, we see that at a distance of three feet, the 5,400 pounds of force would be spread across an area of 8,143 square inches. Four feet from the hole, it would cover 14,476 square inches, and so on. As the force gets more and more stretched out, the proportion of it that would be working to push a body out of the plane diminishes. On top of that, the air would be free to flow around the passengers in their seats, which would make its impact still weaker. Since the hole was in the ceiling of the plane, any decompressive force would have had to act against the full body weight of any passengers, lifting them up and out of their seats before it could eject them in a gust of air.
http://www.slate.com/id/2290316/?GT1=38001