Hi! My name is Eric, and like a number of the bloggers in the new Huffington Post Science section, I'm a scientist. An astrophysicist, to be exact. Unlike many of them, I've never won a Nobel prize. Even if I find ET, someone else will get the prize. It doesn't bother me much. Not having a Nobel means I don't have to talk about big picture stuff or seem particularly wise. It also means I can put an equation in my post. Like all scientists, I like beer, football, and explosions. So we can talk about media stereotypes of scientists in a later blog. We can also explore issues from the Big Bang Theory to The Big Bang Theory. And we'll talk about life on other planets and life on the only planet where we know it exists. We'll talk about climate change, and how to tread water while waiting for the rescue boats.
Last week, I was in a hotel lobby reading the USA Today. Like 95% of Americans, I only read the USA Today when I'm staying in a hotel. That factoid was on the cover. When I got to the letters section, I found a heated discussion was about Alec Baldwin being put off an airliner for using his cell phone and the arguments were about whether a cell phone could down an airliner. Opinions ranged from "a cell phone can't effect an airplanes instruments" to "there have been cases of navigation errors due to cell phones."
One fun part of being a scientist is you don't have to know the answers to questions. Even if you can't get an exact answer, you can make an estimate based upon facts you do know. In my business, one of the most famous examples of such an estimate is the "Drake Equation" which an astronomer named Frank Drake came up with in 1961 to estimate the number of civilizations in the Galaxy with which we could potentially communicate. It looks like this:
It's got stuff we don't know on the left side (number of communicating civilizations) and on the right side things we might possibly know some day like the Galactic star formation rate and the average number of earth like planets per star. I won't go into more detail because we've been talking about that equation for 50 years. Maybe later. But scientists use similar equations all the time. So with no further ado I introduce you to the "Baldwin Equation." (First rule of science: when your equation is talking about hundreds of potential deaths, name it after someone else. Alec can always claim its about Billy.) Here's the Baldwin Equation.
Nc = Rf np fph fon pc
It's pretty simillar to the Drake Equation. Nc is the number of crashes per year caused by cell phones. Rf is the rate of airline flights (flights per year, about 10.4 million), np is the number of passengers per plane (an average of 264), fph is the fraction that have cell phones (somewhere around 90% in U.S.). fon is, the fraction of cell phones that are left on during a flight a different story. I don't know of any studies that say what that fraction is, so we'll have to go on my mostly subjective impression. I've noticed that smart phones are very likely to be left on, probably because they take a long time to start up. I only remember one time that I saw someone actually turn an iPhone off on a flight. This includes flights where the flight attendants explained the process for turning off an iPhone. I've also never seen anyone turn off an iPad.
On the last flight I took, among the 12 people in my row and the row ahead I counted 10 cell phones and four got left on. The guy sitting next to me turned up his ringer and put in the seat pocket. I guess he was expecting an important call. Apparently nobody told him that his chances of successfully receiving a call at 38,000 feet are very small. Anyway, that's 40% of the phones being on.
The product of those terms, 1 billion, is an approximation of the number of cell phones that fly in the U.S. annually in a powered on state. pc which we haven't defined, is the probability that a single cell phone will cause a crash. We don't know what pc is, other than that is isn't a big number or planes would be falling out of the sky, and that it probably isn't zero. If we assume that nothing has changed in the number of phones flying in the last 5 years, we can say that it's likely that pc is less than one in 5 billion. If you put that number in for pc you get a crash every 5 years, which we haven't had.
So what has this exercise told us? Your cell phone is very unlikely to cause a crash. But lets look at it from the FAA's perspective. They don't know what pc is either, and they have to worry about the effects of billions of phones. One of those billions of phones may have been dropped or gotten hit with a cosmic ray in a way that makes it broadcast on the wrong frequency. But you say "The chances of that are a billion to one!" With two billion phones flying annually, that would be two crashes a year. The probability of a crash increases with the number of powered on phones, and for the FAA the only acceptable number of crashes is zero. That means no powered on phones, and hence the rule. If they drop the rule, the risk of a crash triples, and if pc is high enough, that could mean a crash a year.
What does that mean for Alec Baldwin? Well, I lied to you. Alec Baldwin didn't get kicked off a plane because his cell phone was on. Alec Baldwin got kicked off a plane for not following the instructions of a flight attendant. Imagine if everyone on a flight decided that they didn't need to follow flight attendant instructions. We've all felt singled out on occasion, if we've flown enough. My prescription is to apologize, do what I'm told, order a drink when I can, and complain to friends later. There's a time and place to fight, and fighting a flight attendant on an airliner is never the time and place.
What does it mean for you? It means that there is a very, very, very small chance that the seven seconds it takes to turn off your phone and the 30 seconds it takes to turn it back on could save 300 lives. Is 37 seconds too inconvenient? The cost to passengers is 37 seconds when they are trapped on an airplane, anyway. And please don't turn it back on until the wheels are on the ground and you've left the runway. In order to keep certified for automatics landing, the crew might be letting the plane land itself. In other words computer might be landing the plane by following radio signals. The last thing you want is a bunch of frequency hopping transmitters splattering signals all over the spectrum when you're a few hundred feet up. If a cell phone can crash a plane, that would be when.
Follow Eric Korpela on Twitter: www.twitter.com/SETIEric