Flying Near The Equator

Maldives radiation-resized

Whew, I just did 4 round trips between Saudi Arabia and the Maldives.  That was 40 hours of flying in one week!

Maldives route-resized

The Maldives are a group of islands (atolls actually) to the south of India.  The country of Maldives actually consists of over a hundred tiny islands.  It’s like no other place on Earth.  Every island has it’s own purpose.  When you land at the airport you’ll have to take a boat to your hotel on another island!  Yes, there is the airport island.  Next to it is the city island.  Between the two is the prison island. And, pretty much, all the rest are resort islands.  They get no hurricanes and the temperatures are decent throughout the year.  There are no dangerous animals.  There are nearly no bugs.  There’s always a warm breeze, but it’s rarely too strong.  The water is clear blue and there’s tons of exotic fish.  Parrot-type birds and giant bats live in the trees.  The place is a paradise of paradises.

Maldive islands-resized

Here’s me on the boat going to our resort hotel.Maldives boat-resized

Enjoying myself in the middle of January.  Sometimes I can’t believe I get paid for this!Maldive1-resized

We did a ton of flying.  A round trip in the G-IV was 10 hours.  Twice we flew all night with no sleep.  It’s been an intense and exhausting week.  But we finally had a full day off yesterday and I spent it snorkeling in the deep blue waters off of Paradise Island Resort.  Amongst all the tropical fish I saw 5 reef sharks.  It was spectacular!

Oh yes, what about the radiation?  I almost forgot.  I did have my meter on and recording during the flights.  So what did we learn?

Radiation levels in the air over the equator are relatively low!  Whereas the gamma radiation levels over the North Atlantic were over 4.0 micro-Seiverts per hour (uSv/hr) the levels near the equator were around 1.8 uSv/hr.  We consistently flew at 40,000′-43,000′ and there was little difference between altitudes.  These results were all between the latitudes of 4 and 22 degrees North.

Here are some graphs of the flights.  I have more, but they look about the same.

This one was southbound.

1 Riyadh to Maldives

This one was northbound.  It drops at the end because I forgot to turn the meter off after we landed.

2 Maldives to Riyadh

This one was southbound.

4 Riyadh to Maldives

It can clearly be seen that the radiation level at the southern end of the route (4 degrees north of the equator) was lower than at the northern end (22 degrees north).

I did discover something interesting, though.  The ground level radiation varied a lot more than it does on the ground at northern latitudes.  During the day, the gamma radiation was about .11 uSv/hr measured on the porch of my beach-front villa.  Every night, in the Maldives, it dropped down to about .06 uSv/hr.  As we are measuring with Gamma rays, primarily cosmic radiation, these results make sense.  At night the Earth is blocking the sun’s rays and the radiation level drops.  I have not seen this extreme variation at home (36 degrees north) or anywhere else.   The bulge of the Earth between the meter and the sun has a marked affect.

However, as you can see from the graphs above, the effect is not magnified in the upper atmosphere.  Day or night it’s about the same.  There’s a slight rise during the day, but only a little.  The affect is of little note compared to the giant rise in radiation levels from the change in altitude.

Tomorrow I’m flying to Berlin :-0


Radiation Drop


The north and south poles of the earth allow more cosmic radiation through because the earth’s magnetic field, at these points, is weaker.  The majority of electrified particles arriving at the earth, via the solar wind, are deflected around it by the magnetic field of the earth.  An electrified particle is called an ion and ions, obviously, have positive or negative charges.  Many of these ions are radioactive.  Some radioactive particles, such as free neutrons (technically called secondary neutrons), don’t have a charge.  These particles aren’t stopped by the earth’s magnetosphere, but are stopped by the earth’s atmosphere.  So we really have two things protecting us from cosmic radiation.  The magnetosphere and the atmosphere.  The poles are less protected by the magnetosphere and the upper altitudes are less protected from the atmosphere.  So then it follows that the closer you get to the equator, the less cosmic radiation there will be.  And we proved it with this flight.  As we flew south, the radiation dose rate looked like this:


At 41,000′ and 46 degrees north latitude, the dose rate was 3.2 uSv/hr

At 41,000′ and 22 degrees north latitude, the dose rate was 2.0 uSv/hr

It was nice to get to some warm air.  Eighty degree weather and a beachfront hotel awaited me in Jeddah, on the Red Sea.


Radiation Over the North Atlantic

I did my first Atlantic crossing in the Gulfstream IV, a couple days ago.  I can’t tell you how cool it is to be in a jet with such great endurance.  I’ve flown a lot of smaller jets that couldn’t even make it across the US without stopping for go go juice.  So it’s really nice to be in a jet with some LEGS!  The flight was non-stop from Savannah, GA to London.  Flight time was seven and a half hours.



Most airliners fly between 30,000′ and 39,000′.  We were up at 41,000′ getting our silly heads cooked like microwave lasagnas!  That’s good news for my blog, but bad news for my hairline!

NAT3-resized  NAT2-resized

According to the data, above, my accumulated dose of Gamma rays went up from my year’s total of 51.12uSv to 75.39.  My calculator’s telling me that’s an accumulation of 24.27uSv in one day!  And, that’s why aircrew need to have dosimeters.

The average radiation at 41,000′ was 4.0 uSv/hr over the North Atlantic ocean.

The track, above, has a strange gap around New York.  That’s what happens when the detector comes unplugged from the iPad.  It keeps recording the radiation data, faithfully, but it normally gets its GPS coordinates from the iPad.  Without the iPad it defaults to 00 oo’oo” North, 00 00’00″West, which is by Africa, as you can see.  When I realized the detector was not all the way plugged in, I fixed it and made sure it stayed in for the rest of the trip across the pond.

Now, here’s something you need know!  I have just found out that there is more radiation up there than just Gamma rays.  Gamma should be the majority fraction, but I need to get more data about the contributing quantities of the other types of radiation.  The following is a list of the types of ionizing radiation that I’m aware of:

  • Gamma ray
  • X-Ray
  • Alpha (a kind of particle)
  • Beta (another kind of particle)
  • Neutron (the unattached, high-energy kind)
  • Electron (These are, supposedly, a different kind than electrical electrons.  A physicist told me it was too complicated to explain!)
  • Proton (the unattached, high-energy kind)

My next project is to find out what levels of radiation these different types contribute to the whole.  When I figure it out, I’ll let you know!

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Personal Dosimeter

I’ve started using my Polismart II as my own, personal, radiation dosimeter.  The device doesn’t need to be plugged into the iPhone to run.  In fact, there’s no ON/OFF switch at all.  It’s always recording.  The battery lasts for weeks, so it actually works great as a dosimeter.

I reset it a few days before the new year and it’s been continuously monitoring radiation ever since.  Normally, a person will only get 1000 uSv per year.  Compare that to the allowed level of a radiation worker (20,000uSv) and you can see there’s a wide variation in the doses people might receive.  As a pilot I know I’ll get much more than 1000uSv per year.  After lots of research on the net, I’m finding an acceptable level of uSv accumulation per year is around 4000.  So that’s what I’m shooting for.

I’ve set the orange level of my Polismart to 4000 and the red level to 20,000.  Here’s the screenshot of my iPhone as it stands right now, January 10th 2014.


Above, you can see that I’ve received 45 uSv of gamma radiation this year so far.  In smaller numbers it shows that I’m in a radiation environment of .10uSv/hr and at this rate I’ll get to my first threshold of 4000 in a little under 4 years.  Pretty slick!

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New Years Day – 2014

Howdy folks!  It’s been a long time since I posted any results.  I spent a bunch of weeks training in the simulator.  The flight simulation may be accurate, but the simulation of radiation at flight altitude was way off!  Then I went to work for two weeks but forgot to bring my detector!  Then vacation, etc. and the end result is two months with very little data.

Anyway, I do have some results from Christmas vacation flights.  Again, like before, these were relatively low altitude flights, and the results were, predictably, low.  But, as promised, I’m posting everything, low and high.

The location for these flights was in the Northeast, US.

New Year 2014

December 24th 2013

Raleigh-Durham, NC to Philadelphia, PA:

Max radiation at 25,000′ – .96 uSv/Hr

Min radiation at 25,000′ – .92 uSv/Hr

Average radiation at 25,000 – .93uSv/Hr

Philadelphia, PA to Burlington, VT

Max radiation at 25,000’ – 1.35 uSv/Hr

Min radiation at 25,000’ – 1.14 uSv/Hr

Average radiation at 25,000’ – 1.27 uSv/Hr

December 30th 2013

Boston to Raleigh-Durham

Note:  Due to turbulence, the flight crew changed altitude a lot in search of smoother air.  So I got some data for a few different altitudes, as shown below:

Average radiation at 26,000’ – 1.26 uSv/hr

Average radiation at 24,000’ – 1.26 uSv/hr

Average radiation at 22,000’ – .74 uSv/hr

Average radiation at 20,000’ – .76 uSv/hr

Dallas to Raleigh at 35,000 Feet

The night of November 26 I flew from Dallas, TX to Raleigh-Durham, NC.  Maximum altitude was 35,000 feet.  However, it was really turbulent so the crew elected to descend to 29,000 feet after 15 minutes and stay there till descent an hour later.

On the ground in Dallas, the radiation level was .06 uSv/hr (micro-Seiverts per hour).

At 29,000 feet the average radiation level was 1.5 uSV/Hr

At 35,000 feet the average radiation level was 2.4 uSv/Hr

The flight departed at midnight, Eastern Standard time.  Flight duration from wheels up to wheels down was 2 hours and 5 minutes.

Total radiation dose and the max radiation received can be seen in the screen shots below.

DFW-RDUTotal-resized    DFW-RDUMax-resized

If I’d stayed on the ground in Dallas I would have received .126 micro-Seiverts of radiation.  Instead, I received the above quantity of 2.74 micro-Seiverts.

The objective, here, is not to convince you to stay on the ground and never fly.  No way.  The radiation received on short flights like this, flown once in a while, ads very little to ones total, yearly count.  For example, between this flight and my last flight three weeks previous (see previous post) I received 37.3 uSv while hanging out in Dallas.

We want to keep our annual radiation dose under 4,000 micro-Seiverts per year.  Living in Dallas, one would get about 500 uSv per year from background radiation.  If one flew every 3 weeks on a flight like this, one would only get another 50 uSv.  That totals 550 uSv per year.  Far, far below the accepted “safe dose” for the public.

In a few weeks, I’m supposed to do a flight to Saudi Arabia.  It will be interesting to see what 16 hours at varying altitudes and latitudes will total up to.

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First Flight

I flew on American Airlines from Raleigh-Durham, NC (KRDU) to Dallas, TX (KDFW) on November 3rd.  It was my first trial of my gamma ray detector.

Being in the back of the plane, I was able to watch the detector as we took off and climbed up to 28,000 feet.  It was a low altitude flight, presumably to defeat headwinds from the west.  But the point is, I wasn’t in the pilot seat so I had a lot of time to watch the detector.  As we climbed in altitude the digits rapidly climbed from .09 uSv/hr to 1.5 uSv/hr in the air.  Later, the numbers climbed some more, and over Little Rock, Arkansas, the numbers peaked at 1.79 uSv/hr.  Then, as we descended into Dallas, the gamma rays quickly died down to ground level which has ended up being a constant of about .05-.07 uSv/hr here in Dallas.

Here I am (looking dumb because I’ve been in the Gulfstream class all day) at Flightsafety with my iPad.  The Polismart II detector is sticking out the bottom.


And now I know that Dallas is a very, very low radiation place!  In terms of radioactivity, it’s a good place to live.  Raleigh was usually nearly twice as high (.11 or so).  But I’m splitting hairs.  Both places are so near zero compared to flight altitudes that it doesn’t even matter.

1.79 uSv/hr, the peak on this flight, is quite a bit lower than what I’d been predicting.  The reason is that we were:

  1. At low(ish) altitude (30,000’)
  2. At low latitude (35 degrees North)

So, yes, there’s much, much more radiation in the upper atmosphere than on the ground!  It’s not that I had a doubt.  But it was just really interesting to see the numbers clicking up with the altitude, in real time, on my iPhone!

In the future, I’ll be creating a neat way to view data, but, for now, here’s the raw screen shots of the flight.

Here is the flight path, as recorded on my phone during the flight.  You can see the highest reading in the upper-left corner.  There is a gap in the route because my phone lost GPS coverage for a little while.  The image on the right is the total dose received for the entire flight.

RDU-DFW Route            IMG_0127

If I’d stayed at home, I would have received about .23 uSv during the two and a half hours I was actually in the air.  Instead, I got 3.01.

It was a good trial run.  Over the next year I’ll be gathering data around the world.  Keep checking back to see the numbers I get.  And as I educate myself on this subject, I’ll post the basic information that flyers need without all the geek engineering terms that are so prevalent in radiation related websites.