Am I safer not flying Qantas?
November 4, 2010 2:36 PM Subscribe
I just heard that Qantas airlines never had a fatal accident. Statistically speaking, if I fly with them am I more or less subtle to suffering a fatal accident? Why?
I am not flying Qantas and not really concerned, since I know flying is a rather safe transportation.
My question is based solely in a curiosity I always had. Like for instance, if I win in the lottery, but at a smaller prize (like guessing 4 numbers right instead of the 6 that would get me the real prize), am I less likely to win the Lottery main prize in the future?
I am not flying Qantas and not really concerned, since I know flying is a rather safe transportation.
My question is based solely in a curiosity I always had. Like for instance, if I win in the lottery, but at a smaller prize (like guessing 4 numbers right instead of the 6 that would get me the real prize), am I less likely to win the Lottery main prize in the future?
Best answer: if I win in the lottery, but at a smaller prize (like guessing 4 numbers right instead of the 6 that would get me the real prize), am I less likely to win the Lottery main prize in the future?
No, you are just as likely to win in future. Every time you buy a ticket, you are 1 in [?] to win, regardless of previous wins.
I just heard that Qantas airlines never had a fatal accident. Statistically speaking, if I fly with them am I more or less subtle to suffering a fatal accident?
You are less likely to suffer a fatal accident with them than with certain other airlines, but simply because Qantas's record so far suggests that they are a relatively safe airline.
posted by Marquis at 2:40 PM on November 4, 2010
No, you are just as likely to win in future. Every time you buy a ticket, you are 1 in [?] to win, regardless of previous wins.
I just heard that Qantas airlines never had a fatal accident. Statistically speaking, if I fly with them am I more or less subtle to suffering a fatal accident?
You are less likely to suffer a fatal accident with them than with certain other airlines, but simply because Qantas's record so far suggests that they are a relatively safe airline.
posted by Marquis at 2:40 PM on November 4, 2010
The lottery example is slightly different - every draw you enter has the same odds. Winning one time, or a hundred times, or no times, has no effect at all on the next draw you enter. If you win the jackpot tomorrow then it's highly unlikely you'll win it the next day, but no more unlikely than it is for any other person to win it.
The difference with airlines, however, is that not every company is created equal. A company with a good safety record probably has that record because they hold their aircraft and their pilots to a higher standard than other companies. For this reason, flying Qantas is safer than El Cheapo Backyard Airlines in some impoverished country.
Statistically, the lack of an accident so far means a fatal accident on Qantas is less likely, not more, than other airlines.
posted by twirlypen at 2:44 PM on November 4, 2010 [1 favorite]
The difference with airlines, however, is that not every company is created equal. A company with a good safety record probably has that record because they hold their aircraft and their pilots to a higher standard than other companies. For this reason, flying Qantas is safer than El Cheapo Backyard Airlines in some impoverished country.
Statistically, the lack of an accident so far means a fatal accident on Qantas is less likely, not more, than other airlines.
posted by twirlypen at 2:44 PM on November 4, 2010 [1 favorite]
There's an easy demonstration of the principle foursentences mentions.
Say you flip a coin ten times. Each time it comes up heads. What's the probability of that occurring? Simple: 50%^10 = .1% or so, or one in a thousand. (Actually, 1/1024.)
Now that you've come up heads ten times in a row, what are the odds that the next flip is heads? Even simpler: 50%.
posted by supercres at 2:52 PM on November 4, 2010
Say you flip a coin ten times. Each time it comes up heads. What's the probability of that occurring? Simple: 50%^10 = .1% or so, or one in a thousand. (Actually, 1/1024.)
Now that you've come up heads ten times in a row, what are the odds that the next flip is heads? Even simpler: 50%.
posted by supercres at 2:52 PM on November 4, 2010
Also, the premise is incorrect. At least it is if you trust Wikipedia more than you trust Rain Man.
posted by .kobayashi. at 2:54 PM on November 4, 2010 [1 favorite]
posted by .kobayashi. at 2:54 PM on November 4, 2010 [1 favorite]
If you're talking about the gambler's fallacy: no, Qantas isn't somehow racking up points towards an accident. The line that there's no safer time to fly than on the day of another plane crash is nothing more than black humour.
Logistically speaking, Qantas doesn't fly anywhere near the number of routes as, say, a US carrier that has dozens of planes on domestic flights at any minute of the day. It has a relatively small and modern fleet, which generally makes maintenance work easier, though as the A380 engine failure suggests, that can also make an airline an advanced beta tester for new planes.
The statistical data places the highest risk on commercial airlines in the developing world (which often fly badly-maintained, hand-me-down planes), short-haul flights, light aircraft and helicopters. Once you get up to the big airlines in the developed world, you're generally dealing with tiny statistical differences.
posted by holgate at 2:55 PM on November 4, 2010
Logistically speaking, Qantas doesn't fly anywhere near the number of routes as, say, a US carrier that has dozens of planes on domestic flights at any minute of the day. It has a relatively small and modern fleet, which generally makes maintenance work easier, though as the A380 engine failure suggests, that can also make an airline an advanced beta tester for new planes.
The statistical data places the highest risk on commercial airlines in the developing world (which often fly badly-maintained, hand-me-down planes), short-haul flights, light aircraft and helicopters. Once you get up to the big airlines in the developed world, you're generally dealing with tiny statistical differences.
posted by holgate at 2:55 PM on November 4, 2010
Don't miss the other side of the math, which is that Qantas is a significantly smaller airline than, say, American Airlines, flying fewer planes and fewer routes to fewer locations. The commonly tossed around "safest airline" anecdotes likely don't control for size.
Qantas -- 136 airplanes, 150 destinations
American -- 634 airplanes, 260 destinations
posted by Cool Papa Bell at 2:59 PM on November 4, 2010 [1 favorite]
Qantas -- 136 airplanes, 150 destinations
American -- 634 airplanes, 260 destinations
posted by Cool Papa Bell at 2:59 PM on November 4, 2010 [1 favorite]
Like for instance, if I win in the lottery, but at a smaller prize (like guessing 4 numbers right instead of the 6 that would get me the real prize), am I less likely to win the Lottery main prize in the future?
No. The lottery is what statisticians refer to as a series of "independent events" -- this means that the previous winners don't change the probability of winning this time. Every time you play the lottery, you have the exact same chance to win. It's worth noting that it is much less likely to win twice than it is to win once (because the probability of two independent events occurring in sequence is Prob A * Prob B, and these are fractions, so they get smaller when multiplied)... but once you have already won once, you are just as likely to win again as you were to win the very first time you played.
As others have mentioned, Qantas' history of safety probably does make it (very slightly) less likely that you'll experience a fatal accident.
posted by vorfeed at 3:00 PM on November 4, 2010
No. The lottery is what statisticians refer to as a series of "independent events" -- this means that the previous winners don't change the probability of winning this time. Every time you play the lottery, you have the exact same chance to win. It's worth noting that it is much less likely to win twice than it is to win once (because the probability of two independent events occurring in sequence is Prob A * Prob B, and these are fractions, so they get smaller when multiplied)... but once you have already won once, you are just as likely to win again as you were to win the very first time you played.
As others have mentioned, Qantas' history of safety probably does make it (very slightly) less likely that you'll experience a fatal accident.
posted by vorfeed at 3:00 PM on November 4, 2010
I think you're falling for the Gambler's Fallacy.
posted by Chocolate Pickle at 3:06 PM on November 4, 2010
posted by Chocolate Pickle at 3:06 PM on November 4, 2010
I have a friend who likes to say, "If you're worried about someone planting a bomb on your airplane, then bring your own. Because what are the odds that there would be two?"
posted by Buffaload at 3:08 PM on November 4, 2010 [6 favorites]
posted by Buffaload at 3:08 PM on November 4, 2010 [6 favorites]
I'm not sure if you only used the Qantas example as a handy illustration of your probability question, but if you're interested in digging deeper there, I suggest this Ask the Pilot column by Patrick Smith:
Depending how the data is parsed, arguments can be made that various other carriers are statistically safer, even with one or more crashes marring their records. For all its merits, Qantas is a relatively small carrier (126 ships as of 2006, according to Air Transport World), and a high percentage of its flying is medium or long haul. Accidents, infrequent as they are, tend to happen during arrival and departure phases of flight. Per plane, Qantas makes considerably fewer takeoffs and landings than most of its competitors. Others in this category include Singapore Airlines, Cathay Pacific and Emirates, all of whom, coincidentally or otherwise, boast similarly stellar, if not quite perfect safety records.posted by cirripede at 3:10 PM on November 4, 2010
Statistically speaking, if I fly with them am I more or less [likely] to suffering a fatal accident? Why?
Regardless of the lack of accuracy of the Qantas stats, you are to some extent less likely to have an accident in a plane run by an airline with a good safety record because it makes it more likely that that airline has higher maintenance standards than most airlines. They could also have a higher fleet turnover (ie have newer planes in their fleet), which may mean they are less likely to have a failure.
So, as alluded to above, airlines with good safety records generally have a better maintenance record (and corresponding lower component failure rates) and so are less likely to have an accident and/or they're just lucky. However, with two airlines that have identical safety procedures and maintenance procedures, luck and miles flown will also be a factor - the more miles you fly, the more planes you have, the more chance of a failure as something is going to break eventually. The longer you retain each aircraft, the more chance of a failure. So when choosing an airline on safety, you should consider other elements such as these.
Also, being as some accidents are weather or external event related (bird strike, etc) then the maintenance record of the airline becomes entirely irrelevant. It doesn't matter how many incident free miles an airline has if a flock of Canada Geese dive into its flight path.
posted by Brockles at 3:13 PM on November 4, 2010
Regardless of the lack of accuracy of the Qantas stats, you are to some extent less likely to have an accident in a plane run by an airline with a good safety record because it makes it more likely that that airline has higher maintenance standards than most airlines. They could also have a higher fleet turnover (ie have newer planes in their fleet), which may mean they are less likely to have a failure.
So, as alluded to above, airlines with good safety records generally have a better maintenance record (and corresponding lower component failure rates) and so are less likely to have an accident and/or they're just lucky. However, with two airlines that have identical safety procedures and maintenance procedures, luck and miles flown will also be a factor - the more miles you fly, the more planes you have, the more chance of a failure as something is going to break eventually. The longer you retain each aircraft, the more chance of a failure. So when choosing an airline on safety, you should consider other elements such as these.
Also, being as some accidents are weather or external event related (bird strike, etc) then the maintenance record of the airline becomes entirely irrelevant. It doesn't matter how many incident free miles an airline has if a flock of Canada Geese dive into its flight path.
posted by Brockles at 3:13 PM on November 4, 2010
Rainman. In the film Rainman, Dustin Hoffman's character said that Quantas never had an accident.
Equally unreliable Wikipedia says otherwise.
But the fact that Quantas has grounded its aircraft whilst other airlines flying the same configuration (Rolls Royce engines) have not (Lufthansa for example) suggests that safety has something of a greater priority at Quantas.
posted by three blind mice at 3:15 PM on November 4, 2010
Equally unreliable Wikipedia says otherwise.
But the fact that Quantas has grounded its aircraft whilst other airlines flying the same configuration (Rolls Royce engines) have not (Lufthansa for example) suggests that safety has something of a greater priority at Quantas.
posted by three blind mice at 3:15 PM on November 4, 2010
Odd timing, even though it doesn't really answer your question:
Qantas Halts A380 Flights After Engine Explosion.
posted by colfax at 3:15 PM on November 4, 2010 [1 favorite]
Qantas Halts A380 Flights After Engine Explosion.
posted by colfax at 3:15 PM on November 4, 2010 [1 favorite]
Statistically, the lack of an accident so far means a fatal accident on Qantas is less likely, not more, than other airlines.
I take issue with that. The true measure of risk is "deaths per passenger mile". Other airlines might have had fatal incidents but after 1,000,000,000 passenger miles, yet Qantas may have no fatalities after 200,000,000 passenger miles. This does not at all mean that Qantas are "safer".
posted by Biru at 3:23 PM on November 4, 2010
I take issue with that. The true measure of risk is "deaths per passenger mile". Other airlines might have had fatal incidents but after 1,000,000,000 passenger miles, yet Qantas may have no fatalities after 200,000,000 passenger miles. This does not at all mean that Qantas are "safer".
posted by Biru at 3:23 PM on November 4, 2010
Keep in mind that Qantas, being based in AUSTRALIA, is geographically isolated from the rest of the world, thus their average flight time is longer. Most airline fatalities happen at takeoff and landing. Qantas performs fewer takeoffs and landing than other airlines of similar size.
posted by dawdle at 3:34 PM on November 4, 2010 [1 favorite]
posted by dawdle at 3:34 PM on November 4, 2010 [1 favorite]
There is a great scene in Nothing in Common where Tom Hanks' character addresses this very issue with a fictional airline that is his client for an ad campaign. It doesn't really answer your question so much as illustrate that people are bad at making these sorts of risk calculations. It's worth watching. It isn't on YouTube but is available to stream from Netflix. The scene starts at the 50 minute mark.
posted by jeffamaphone at 4:04 PM on November 4, 2010
posted by jeffamaphone at 4:04 PM on November 4, 2010
Response by poster: Wow, you guys blew my mind with your answers! Thank you!
posted by fcoury at 5:43 PM on November 4, 2010
posted by fcoury at 5:43 PM on November 4, 2010
The thing cirripede and dawdle mention is significant.
Almost all QANTAS sectors are long or very long, hence the number of takeoffs and landings per day within the the QANTAS fleet is lower than you would find in many other fleets with same number of passenger-miles. As Patrick Smith says takesoffs and landings are where most of the risk is.
posted by southof40 at 7:59 PM on November 4, 2010
Almost all QANTAS sectors are long or very long, hence the number of takeoffs and landings per day within the the QANTAS fleet is lower than you would find in many other fleets with same number of passenger-miles. As Patrick Smith says takesoffs and landings are where most of the risk is.
posted by southof40 at 7:59 PM on November 4, 2010
Google "qantas maintenance record" or just "qantas maintenance".
posted by Ahab at 8:16 PM on November 4, 2010
posted by Ahab at 8:16 PM on November 4, 2010
Thanks fcoury: Qantas 747 jet lands after engine trouble
posted by Razzle Bathbone at 7:50 AM on November 5, 2010
posted by Razzle Bathbone at 7:50 AM on November 5, 2010
« Older Heated Clothing? I'm Warming Up To The Idea :0) | What should my teeny-bopper pop song be about? Newer »
This thread is closed to new comments.
If this is a math puzzle about a random event -- as it appears to be -- the answer is that you are neither more likely nor less likely to crash. "Probability has no memory" of what happened last time, they like to say.
If this is a real-life puzzle, consider: the fact that Qantas has never crashed, may tell us something about their safety precautions.
posted by foursentences at 2:40 PM on November 4, 2010