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Plane Answers: A pilot's seatbelt sign philosophy and aircraft accident odds
Can someone tell me why the pilot sometimes turns on the seatbelt sign but it's seemingly for no reason? I recently flew Dubai to London and he (or she) kept putting it on however nothing happened. Especially annoying as I needed the bathroom at the time?
There are a couple of possible explanations for a seatbelt sign that turns on and off frequently.
Occasionally we'll get reports from airplanes in front of us warning of turbulence ahead. It's best to get the seatbelt sign on if we get a report like this to prevent any injuries to passengers standing in the aisle.
Deciding when to turn the sign on after experiencing some un-forecasted and unreported bumps can be a challenge. Some pilots don't mind turning the sign on and off as the conditions permit and some will turn it on, only to forget about the sign when the ride improves, thus making every passenger feel like a criminal for using the lavatory for the rest of the trip.
There are some pilots who are concerned enough about the liability involved when turning the sign off that they'll insist on keeping it lit for the duration of the flight. This actually creates a riskier situation since passengers will disregard the sign, even during periods of turbulence, completely eliminating the point in having a sign in the first place.
There's another explanation that might surprise you. Pilots have been known to get calls from flight attendants asking for the sign to be turned on so they don't have to deal with people becoming stuck in an aisle between their carts or otherwise getting in the way of the service.
And occasionally there can be a rather large group of people congregating around the galleys chatting it up. One of the ways to disperse this crowd had been to use the seatbelt sign. This isn't exactly what the sign was intended for, of course.
In light of the Air France crash, I am curious to know if it is indeed true that passengers pass out first, due to loss of cabin pressure, even before a plane hits the water (assuming it didn't explode in the air)?
What are the odds of this happening to me? Are the odds of this happening greater or less than winning the lottery?
P.S. This is my take: when I get on the plane, my odds are 50 / 50 : 50% chance that I live and 50% chance I don't. (haha, ok, joking...)
If the flight were to depressurize, and assuming the passengers couldn't get to their oxygen masks during the descent, then there is a limited amount of time until they will pass out. This time of useful consciousness varies depending on the altitude.
At FL350 (35,000 feet) that time is only 30 to 60 seconds. However if the airplane is descending rapidly, the lower altitude will likely wake people up.
It's a morbid thought, for sure, but since you brought up statistics, let's look at the odds of dying in an airline accident a moment.
According to the Insurance Information Institute, the odds of losing your life in any given year is 1 in 502,544 and over an entire lifetime, it drops down to 1 in 6,460.
That's much better than the 1 in 84 odds over a lifetime that a person could be killed in an automobile accident. It seems to me the most effective way to save lives on a large scale would be to improve auto safety.
The odds of winning the lottery are reported at between 1 in 18 million for a state lottery to as low as 1 in 120 million in a multi-state contest. So, in fact the odds of an airplane accident are greater than the average person's odds of winning the lottery.
But the automobile odds show that driving is really the risky activity – 77 times riskier than flying, yet it's unusual to hear of anyone afraid of driving.
Do you have a question about something related to the pointy end of an airplane? Ask Kent and maybe he'll use it for the next Plane Answers. Check out his other blog, Cockpit Chronicles to travel along with him at work.
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