Updated: Oct 2, 2018
by Hervey Allen
On the top-10 busiest air routes in the United States* there are approximately 1,400 commercial, cargo and charter flights each day. Rads on a Plane has been tracking these routes since October of 2017. You can view all this data, sort it and play with it on our Interactive Flight Data.
We also maintain a Hot Flights Table, which we update every day. The table reveals a pattern showing that charter flights, on average, fly higher than commercial flights and, again, on average, receive a higher dosage of cosmic rays over similar distances or times of flying. This makes sense as the higher you fly, the greater the dose rate of cosmic rays.
So, why do charter flights fly higher than regular commercial traffic?
For a number of reasons, including being able to avoid commercial traffic routes by flying above them, flying above weather for a smoother ride and the higher you fly, the faster you go.
So how high is high?
We did some digging in our data and came up with a few interesting numbers. For starters, since October of 2017 there have been over 370,000 commercial flights and 11,200 charter flights on the top-10 busiest air routes in the United States. Of all these flights, the average maximum altitude for commercial traffic has been 34,400 feet and for charter traffic it has been 35,700 feet.
Not much difference, but we have noticed a trend that you can see by going to our Daily Hot Flights table/ Almost always, the highest charter flights go significantly higher than the highest commercial flights. As a matter of fact the numbers are quite interesting:
You can draw quite a few conclusions from this, but the bottom line is that 1 in 8.5 charter flights go over 45,000 feet while less than 1 in a 100 commercial flights are likely to do this. And, almost half of all charter flights flew above 38,000 feet.
So, does flying higher mean a higher dosage on average? While the higher you fly the higher your rate of exposure. But, if you fly faster, then perhaps you are only exposed to these higher rates for a short period of time vs. commercial flights. There are many ways we could look at our data to figure this out. For this post we'll look at the overall trend.
Remember, these numbers are for over 370,000 commercial flights and 11,200 charter flights since October 2017 on the top-10 busiest air routes in the United States.
Dosage is in uGy or micrograys. Around 10 uGy is a typical dental x-ray
For flights less than 2 hours total radiation dosage is very similar for both commercial and charter flights. For longer flights (4+ hours), however, passengers are exposed, on average, to over 40% more radiation than on commercial flights.
So, yes, luxury can come at a price. Not only in the cost of the ticket, but in the amount of exposure you experience if flying for 2 hours, or longer. Of the 11,200+ charter flights we measured 40% were in the air for over 2 hours.
Stay tuned for more posts about how cosmic radiation is affecting airline travelers.
*Top-10 busiest air routes (United States)