I had reason to ask this question when travelling recently with my wife, as we all do at one time or another when traveling by air. I was on an Indian flight to New Delhi from Lucknow, and as we approached New Delhi airport in the dark of early evening, we entered a heavy thunderstorm and probably were caught in the worst turbulence I have ever encountered. Suddenly I could see lights on the ground below us, and they were alarmingly close. Just then the pilot gunned the engine and announced that he would try one more pass in an attempt to land. “If it didn’t work, what then?” I asked myself. My thoughts were centred on how experienced the pilot was? And I wondered how much human error can still play into air travel today. Don’t planes land irrespective of bad or good weather? Aren’t last-minute pilot decisions a thing of the past? Perhaps no is the answer one gets when one thinks about the tragic loss of 228 passengers aboard the Air France flight 447 to Paris…

How risky is flying? In numbers, the annual risk of being killed in a plane crash for the average American is about 1 in 11 million. Yes, the risk is pretty small when we compare this risk to the annual risk of being killed in a motor vehicle crash for the average American, which is about 1 in 5,000. But there are problems in this method and main one is not about comparing apples to oranges, but that no one is an average American — we all have different needs when it comes to air travel some do it more frequently and others probably never. Simply put, the risk one gets by dividing the number killed in plane crashes by the total population of a country like the US may be a good general guide to whether the risk is big or small, but it’s not specific to one’s personal risk.

Considering the impersonal nature of this risk, the other problem is what to use in the denominator? Using the total population in the denominator results in risk for the average person, using flights all passengers take, gives the risk per flight, while using the total number of miles all of them flew, gives the risk per mile. So which one to use? — depends on our flying habits. Some people take short flights more often, while some take longer ones more often when we know that an overwhelming number of plane crashes occur only during take-off and landing. Thus, the risk might be independent of the distance you fly, but instead depend on how frequently you fly. For frequent flyers collecting those precious miles, risk per flight is a better measure, while for those travelling on one of those non-stop long range flights between New Delhi and New-York, the risk per miles is, perhaps, a better indicator. But for a frequent flyer travelling long distances both risks measured per flight and per mile become vital.

That’s not all, there is another problem: do we calculate the risk of flying based on one year, or an average of 5, or 10, or 20 years? Taking a one year period might be misleading as that year many crashes might have occurred inflating the actual risk or none might have occurred deflating the actual risk. Whereas, considering average of 5, 10 or 20 years might prove difficult to start with as during this period FAA has issued new rules for safety, September 11, 2001 has happened and many new safety factors, courtesy a number of crashes in the interim, have been imposed — thus changing the conditions in which any such long term averaged risk is measured.

Numbers are a good way to put any risk in perspective and this proves flying to be less risky way to travel than most other means. Yet why did many people applaud after a difficult landing, while many held their nerve when a recent flight on which I was travelling was caught in turbulence — probably there is more to the risk than mere numbers.

Risk perception, as it is popularly called, is shaped by our knowledge of the things we know like possibility of problem with Pitot tubes measuring air speed on A330-200, our recent experiences like the one really scary, turbulent flight once I took to New Delhi, and our life circumstances where my wife might be more afraid of flying when my new born kid is small.

Researchers in psychology like Paul Slovic and Baruch Fischhoff at Carnegie Mellon have found that when we have control (like when we are driving) we are less afraid, and when we don’t have control (like when we are flying) we are more afraid. That probably explains why, in the first few months after the 9/11 attacks, fewer people flew and more people chose to drive. Another “feelings factor” that informs our perception of risk is awareness. The more aware we are of a risk, the more concerned we are. Which explains why, when there is a plane crash in the news like Air France 447, flying seems scarier, even though that one crash hasn’t changed the overall statistical risk much. People are also more sensitive about risks that are catastrophic, which kill people all at once in one place, than we are about risks that are more chronic, where the victims are spread out over space and/or time. Plane crashes, therefore, get more media attention than, say, heart disease that kills 2,200 people in the US each day.

Then there’s the factor the researchers like Lowenstein call dread — a measure of suffering. The nastier a way to die, the more afraid we are likely to be. Dying in a plane crash sounds a lot worse than dying of heart disease, even though the likelihood of dying from heart disease is much higher (1 in 400 per year, for an average US citizen).

Thus, for the Indian who is deciding to air travel and still wants to live longer it is a sane advice to strike a balance between the risk numbers, the life circumstances and the feelings factors associated with air travel risks. Yes, like everyone else, caught by my own affect, I also took a breath of relief when the Indian flight to New Delhi saw lights on ground again and somehow managed to touch ground coming to a final halt!