Solar Flares - Stay on the Ground?

[LH419]

My first post here...

During times of high solar activity, solar flares frequently hit the Earth. During the time of the flare, depending on the intensity of the flare, the ionizing radiation can exceed 20mSv/h (annual dose of a long-range pilot is about 3-8mSv, while radiation workers in Germany receive about 1,5 to 2mSv per year). Although this intensity is seldom reached, a couple of mSv's per hour are a normal for solar flare strikes.

As far as I know, solar flares can be predicted or sufficient alerting time is available. (Is a solar flare a (faster) radiation phenomenon or a (slower) particle stream?)

Looking at the high radiation exposition that one faces when climbing into the stratosphere when a solar flare strikes, I would like to know if pilots are supposed to stay grounded for the time of the hit or if companies do not show leniency if a pilot refuses to fly when a solar flare is approaching.

Happy Landings always
LH419

[LH419]

Is there really nobody among the members of this boards who has anything to say about this issue?!

Well, I didn't think so.

So, please, enlighten me!
LH419

[Checkboard]

Hmmm .. suck on this for a while :):
Radiation & Aircrew (http://www.pprune.org/go.php?go=/pub/gen/radiation.htm)

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Tech Log forum moderator

[Evo7]

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Is there really nobody among the members of this boards who has anything to say about this issue?!

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Well, I guess I'm as qualified as any.

As I understand it, the main risk are things called coronal mass ejections (CME's) which are associated with, but not the same as, solar flares (which emit mainly in the X-ray band). CME's consist of high energy particles (mainly protons and electrons, with some heavier nucleii) which are ejected from the solar corona into the heliosphere (the region around the sun). They move slowly enough to be seen by satellites like SOHO and therefore forcast, at least to a degree.

When a CME 'hits' the earth, the particles are deflected by the Earth's magnetic field, and enter the atmosphere preferentially via the North and South magnetic poles. When they impact atoms in the atmosphere they emit visible light (Green light at 557.7nm for Oxygen)- this is what the Aurora Borialis (literally, the Northern Dawn) is.

The problem, for flight crew and more so for astonauts, is that it does not quite so simple in practice. Not all of the particles eneter the atmosphere via the poles, and for those that don't, the best protection is to be as far under the atmosphere as possible. The higher up you are, the more you get hit. The more you get hit, the higher your radiation exposure is.

Is it a real risk? Hard to know. The Sun is not the only thing to emit high-energy particles, and the earth is being hit constantly from particles from further afield - known as Cosmic rays. Your exposure to those is certainly higher than for someone who spends their life on the ground, but significantly higher? No real answer, although that 23% -&gt; 23.3% risk of cancer quoted in the previous post may represent a real increase and not statistics.

A CME makes NASA nervous - their astronauts have no atmosphere to hide under. However, it isn't clear to me how much a big CME boosts your exposure at 40,000 feet over and above the standard Cosmic Ray background. I'd doubt that you should start cancelling flights over it.

If there's interest, I can look further.

Cheers,

Evo.

[wonderbusdriver]

Check out VC on the subject.("Wozu in die Ferne schweifen, wenn das Gute liegt so nah!")
H.-J. Lebuser is an expert on the subject and has written numerous articles.(albeit in German)
He was quite involved in the new European legislation on the subject of radiation as well.

Airlines have not yet reacted to the possible (!!!) consequences of solar flares etc., since there isn´t enough data yet to confirm possible effects.
All possible "solutions" will cost quite a bit of money though, so they´re rather reluctant.

Also, dig in the pprune archives for more on the subject.

Abgesehen davon, ist der Job, mit oder ohne Strahlung, aufgrund anderer körperlicher Belastungen nicht unbedingt gesundheitsfördernd.

[Evo7]

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All possible "solutions" will cost quite a bit of money though, so they´re rather reluctant.
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Like flying a lead-lined aeroplane?

[wonderbusdriver]

- Not flying higher than FL 290 above a latitude of 50N is one.
The cosmic radiation levels go up in a almost vertical line above FL 290.
- More southerly routings on transatlantic flights.

- Crew rostering can be done accordingly, but you´ll need more crews...etc.

And what will the public think, should it actually be detrimental to their health, too?!

But - as I stated before:
Not enough data yet - Doubt there ever will be enough to show a definite correlation between chromosome abberationsand cosmic radiation.

[LH419]

Dear Checkboard!

Well, I tasted it and spat it right back out! The info from the page is out-dated, and it seems a little one-sided. From the German airline pilots union (VC) I have obtained some information which is much newer and which illuminates the quality of the risk assessments. Unfortunately, it's in German, so it won't be too useful to most of you guys. If there's some interest, I could translate it into English. Sources for the German versions of the 2 documents (in Acrobat Reader format!):
-http://www.vcockpit.de/pages/vcinfo/archiv/strahlen0008.pdf
-http://www.vcockpit.de/pages/vcinfo/archiv/strahlen0006.pdf
-
True, the ICRP 60 still seem to be the newest limits by the ICRP, but other sources than this 'closed shop' strongly disagree with the risk assessment of the ICRP. For example, the data used when creating the ICRP 60 limits is 20 years old. In 1996, the Radiation Effects Research Foundation (RERF, the official organisation for the revelation of the effects of Hiroshima and Nagasaki), on the other hand, has published a much more alarming risk assessment. The following risks are based upon an annual dose of 3-6 mSv. ICRP 60: Cancer deaths in Airline Operation: +0.42% to +0.84%. Business Aviation (higher altitudes): +1.3%. RERF 96: +2.1% to +4.2% for airliner altitudes, +6.5% for business aviation. For comparison: The risk to die from a fatal working accident in Germany is 0.1% for 35 years.
Even so, there are several factors that are not being accounted for in the ICRP 60 or RERF 96. One of them is the fact that the radiation in the lower stratosphere consists of especially hazardous types of radiation. High energy ionizing radiation and neutron radiation are supposed to be more damaging than equal doses of other ionizing radiation types. These high-LET-rays make up 50% of the total radiation in airliner altitudes, while they are only 2% of the ground radiation. These rays do not fall under the category where a risk-reduction factor can be justified.
Also, young people are more sensitive to radioactivity and young women are even more at risk to be harmed.

Because jet aviation has only been done commercially for some 40 years, cancer latency times can also affect the statistics. Also, there is very sparse follow-up research available. This means that very few pilots' medical data has been gathered after retiring age.

One final piece that I've read in the Pilots.de forum (also an Ultimate Bulletin Board forum, but with only a little under 3,300 members): Only 40% of all pilots live until the age of 65...

Well, Checkboard, the issue is not so easy after all...

Any Comments?

[wonderbusdriver]

Locker bleiben, der will Dir nix - hat Dir stattdessen wenigstens Links gegeben.

Musst Dich evtl. erst noch an den Ton und den angelsächsischen Humor hier gewöhnen.
Hier gehts NICHT so ab, wie auf der schon erwähnten Site.

[Diver]

I wrote this Solar Warning article some 3 years ago with a few ammendments during last year as the Solar Cycle 23 got well into play. If of any interest to anyone.

SOLAR WARNING!

The Sun has an awesome amount of power. Its electromagnetic spectrum has a level of radiation, that spans infrared, visible and ultraviolet light through the radio spectrum of x-rays, and beyond. It is constantly ejecting atomic and sub-atomic particles of electrons protons and helium nuclei, (Solar Wind).

Although the sun's location is an average of 93 million miles away from earth, light takes just 8 minutes and 40 seconds to reach us. The 'Solar Cosmic Wind' bombards the earth up to a velocity of, 2 million miles an hour. A solar flare has an explosive energy the equivalent of 2 million, million Hiroshima Atomic bombs, (1 atomic bomb had a mass of 10,000 tonnes of TNT) ejecting high-speed masses of hydrogen, helium gas and Solar Protons. Large eruptions on the Sun hurl solar energetic particles that have an energy exceeding 10MeV. Fortunately most of the sun's energy from flares is directed away from earth, but when one makes a direct hit on us, watch out! 'Solar Flares' potentially can have a devastating effect on earth.

The magnetic field of the earth prevents the plasma of the solar wind from directly impinging on the earth's upper atmosphere and ionosphere. The tenuous plasma within the solar wind are subject to large perturbations, known as magnetospheric storms, that are triggered by fluctuations within the solar wind. These storms generate intense auroral displays; magnetic field fluctuations at ground level and often-major disturbances of the upper atmosphere and ionosphere, which disrupts radio communications.

It is now thought that CME's, (Coronal Mass Ejection's) associated with solar flares, may be the main source of most of the potentially damaging energetic particles arriving at the Earth.

Several times every solar cycle, a solar eruption of extraordinary energy creates a brief violent gust in the solar wind, which sets the entire magnetosphere reverberating. When this high-velocity shock wave arrives at the Earth, followed by the magnetic fields, it compresses the daylight side of the magnetosphere to half its normal size. The disturbed magnetic field induces large electric currents in the Earth's surface. The Polar Regions being the most vulnerable where the magnetic defence is at its weakest. This was proven when on the 13 March 1989, a massive plasma storm caused wide spread damage to Quebec's Hydro Electricity generating company, as high currents were induced into the power lines that overloaded the grid.

During Solar maximum up until mid 2002, peaking mid 2000) gigantic magnetic bubbles of Plasma from CME's, expand outward from the Sun. If the Plasma bubble is directed towards the Earth and the CME's magnetic orientation is such that it combines with our magnetic field, this is the time to be concerned. There are more solar flares during solar maximum, also more CME’s adding to subatomic particles that are accelerated to high energies from solar flares to the solar wind. Solar protons associated with this Plasma bubble are so energetic that there is little protection provided by our terrestrial magnetic field. However, the Earth's magnetic field, the Magnetosphere is still our only primary natural defence from both cosmic and solar rays.

The magnetic orientation of the incoming Plasma that originates from the sun is now known to be an important factor. With this knowledge, solar forecasters are able to predict the effect that it may have on Earth more accurately from data provided by the satellite ACE (Advanced Composition Explorer). Depending upon the Plasma's magnetic orientation, it can combine with and penetrate the Earth's magnetic defence right down to the Earth's surface, particularly during the two equinox periods March and September, when the coupling is at its strongest. This can result in, a severe magnetic storm to our geomagnetic flux,which usually lasts for two to four days after a major occurrence. A Geomagnetic disturbance that reaches 'Severe Storm' level, has the potential to cause overloading in power lines, high currents being induced into pipelines which causes corrosion, disruption of mineral surveys, damage to radio navigation beacons, VOR, ADF, ILS, as well as VHF and HF equipment. Disruption to radio, television and satellite transmissions, the degradation or destruction of satellite circuitry, including GPS. All of this in addition to the Cosmic, X-ray, Proton and Electron radiation effects to our human biology and physiology.

Most of you are aware, that the 'Sun's Solar Cycle' peaks approximately every 11 years. The overlap period i.e. the ending of cycle 22 and the beginning of cycle 23 started June 1996. This was the ending of the quiet period (apart from CME's Coronal Mass Ejection’s that occurred during this time) when the rotational twisting of the sun's magnetic field changes its direction.
We are at present four and a half years into Solar Cycle 23 and is expected to be one of the highest on record. It is forecast to peak the mid part of the year 2000. Solar cycle 23 has already produced some significant flares at the time of writing. There will be numerous, potentially damaging flares, to sustain this cycle.

At a workshop held at the Space Environment Laboratory in Boulder Colorado in September 1996, the world's leading solar cycle forecasters met to discuss cycle 23. Dr Richard Thompson of IPS Radio and Space Services predicted that in the year 2000 the average sunspot number would reach the low 160’s.

The sun only has to hiccup during this period for the effect to be magnified many times in the magnetic field and the ionosphere. Those of you who have seen the 'Aurora Borealis' have witnessed one of the visual effects this 'Solar Particle Impulse' has on our atmosphere. This enormous amount of energy, causes excitation of the hydrogen and oxygen molecules. They glow (green for the hydrogen molecules and blue for the oxygen molecules) only a few Km above our cruising levels when flying at high latitudes. Fortunately, our Atmosphere incorporating the Ionosphere and Magnetosphere does protect us from all but the most powerful solar storms.

Much watching, measuring and forecasting is being done by several observatories around the world, notably by NOAAs Space Environment Services Centre, SESC in Boulder Colorado by NASSAs Solar Heliospheric Observatory, SOHO. Also by the Advanced Composition Explorer, ACE, (the most recent satellite observatory launched from Cape Canaveral Air Station in Florida on 24 August 1997) and from IPS Radio and Space Services in Australia among others.

The ACE observatory satellite is situated about 1 million miles from earth and some 92 million miles from the sun. It is constantly observing the sun and its disturbances. ACE is able to provide scientists one hour's notice of a potential problem. This should give satellite operators time to shut down their satellites in order to prevent any damage. The Defence Evaluation and Research Centre, DERA at Farnborough received its Cosmic Radiation Effects and Activation Monitor, CREAM, back on earth when the Shuttle Atlantis landed in October 1997. They hoped that data recorded will help clarify what effect radiation and magnetic storms can have to electronics, after being onboard MIR for 5 days.

You can find out for yourself the effect the sun is having on our geomagnetic flux, by accessing any of the Web pages below or, using the HF radio (conditions permitting)or by telephone. If you monitor the following frequencies 2.5, 5, 10, 15 or 20MHz at Hr + 18min, subject to your location and propagation conditions, or by telephoning 001-303-497-3235 (the recording lasts for 40 seconds). You will hear the following, for example: -..... "Solar-terrestrial indices for(UTC+Date) as follows; Solar flux (number) and Boulder A index (number). Repeat, solar flux (number) and Boulder A index (number). The boulder K index at (UTC) on (date) was (number) repeat (number). Solar-terrestrial conditions for the last 24 hours follows: Solar activity was (Very Low or Low or Moderate or High or Very High), the geomagnetic field was (Quiet or Unsettled or Active or Minor Storm or Major Storm or Severe Storm). The forecast for the next 24 hours follows: Solar activity will be (Very Low or Low or Moderate or High or Very High). The geomagnetic field will be (Quiet or Unsettled or Active or Minor Storm or Major Storm or Severe Storm)"

What does this all mean? Solar Flux is a measurement of the solar radio emission intensity at a frequency of 2800 MHz, (known also as the 10.7cm flux). The solar radio emission has been shown to be proportional to sunspot activity. The Solar Flux number referred to in the message, (as a 'Solar Flux Unit' s.f.u), is recorded daily using a radio telescope at Ottawa at 17:00 UTC and is forwarded to SESC at Boulder. The minimum s.f.u. Number is 67 and goes up to 400 s.f.u. The Boulder A Index is an average measure of the geomagnetic activity. The A indices range from 0-400. The Ap index is averaged out to give a global figure taking into account variations at local recording sites derived from the K index, which is a 3 hourly magnetometer measurement comparing the current geomagnetic field orientation and intensity to what it would have been under geomagnetic quiet conditions. K index measurements are taken at sites throughout the globe each carefully adjusted for the characteristics of their location, the K indices range from 0-9. Solar Activity is a measure of energy releases in the solar atmosphere, observed by X-ray detectors on earth orbiting satellites.

The categories of x-ray class flares are based on their x-ray output, measured on earth in the 0.1 to 0.8 nm (Nanometre) wavelength band. M class and X class flares being the most powerful. Geomagnetic Field, is the earth's magnetic field lines between the two poles being disturbed at surface level by up to 5%. The largest effects are at high latitudes, in the auroral ovals in the ionosphere and between the ionosphere and the magnetosphere.

Geomagnetic Activity Ap Index (Ap = Planetary A Index)

0-7 = Quiet
8-15 = Unsettled
16-29 = Active
30-49 = Minor Storm
50-99 = Major Storm
100-400 = Severe Storm

For further reading I would recommend any of the books available on the subject one for example, Sun Earth And Sky by Kenneth R..Lang ISBN 3-540-58778-0.

With the increasing number of civil transport aircraft having had computer systems incorporated, some pilots are concerned with their reliability, especially if one or more of the computers are rendered inoperative with little manual backup.

What effect can this have on computers onboard aircraft?
Protons and electrons could possibly be induced into the fuselage skin, penetrating the fuselage and its gaps, through cockpit and other windows onto the inter-computer feeder and signalling cables, causing 'Deep Dielectric Charging' within the computers' circuitry (electrostatic flashover) destroying the very sensitive micro-processors. This has already occurred to satellites, during the Sunspot peak of cycle 22. In March 1989, the GOES7 satellite received a dose of high-speed protons from an X-12 category flare, which degraded its solar panels in one day as much as would normally have been expected in one year. On the 10 January 1997, the AT&T 'Telstar 401' satellite was knocked out.

So, could it occur to the computers on board our aircraft?
Although Concorde our longest flying fly-by-wire civil aircraft flies at altitudes up to 60,000 ft, in the most inhospitable and potentially dangerous environment, where radiation levels are many times greater than that below 30,000 ft has, so far, withstood 2 Solar cycles. But Concorde was designed during the 1960's before microprocessors were thought of, using I suspect a combination of the then relatively new invention, the Transistor along with Valves. The use of valves over solid state devices is important here, because valves are able to withstand far better the effects of damaging Cosmic and Solar Rays.

One possible way of reducing the chance of an aircraft being affected by one of these solar storms, is to have a Solar and Geophysical forecasting service available in briefing rooms at major airports in the world. This could provide a service to operators and aircrew, as with weather forecasting, information on when and how to avoid (if it is at all possible) areas of the most intense radiation. This could perhaps advise the closure of Polar Routes, not to fly at latitudes north of 60 deg North (or south of 60 deg South) or not to fly above 30,000 ft, when the 'Solar Activity' is at 'Very High' levels and the 'Geomagnetic Field' is at 'Severe Storm' levels. There is, I believe sufficient Solar data being gathered today to provide this kind of service. Our own government scientists at the Defence Evaluation and Research Agency, DERA, at Farnborough, are aware of the radiation effects on aircraft computer systems. Are pilots being provided with all the information?

The use of computers has of course changed our whole approach to aviation in many cases for the better; we are constantly being told this is the way of the future, which there is little doubt. However, are we the guinea pigs of today, testing out the hardware of computer controlled flight controls and systems in everyday operational use? Can one take for granted the integrity the manufacturer place on their computerised flight control systems? Was the Electromagnetic functionality testing of computerised systems, by manmade RF energy of only a few hundred megawatts, good enough? Is the computer 'Faraday Screening' sufficient to protect the computer circuitry from external electromagnetic interference? Some of the many questions I am curious to know the answers to. Are you ?

Arguments and criticism over the technology has only been scratching at the surface. Any known studies that have been carried out, as far as I am aware, have only looked at the Pilot interface problems associated with the FMS, (Flight Management System). Perhaps a more in depth study should be conducted, questioning the basic integrity of the technology.

Data from the FDR (Flight Data Recorder), would most likely be, inconclusive after an incident. Unlike conventional hydraulic-mechanical aircraft, would the AAIB be able to find evidence of that microprocessor which had been zapped? The words of Pierre Ziegler still ring in my ears today as a warning to us, after earlier incidents to computer controlled aircraft, with his crude analogy he stated: ........'We know there was not an atmospheric event. We know it was not the aircraft, so it must be the pilot'.........

Web references
http://www.sec.noaa.gov
http://www.nasa.gov
http://www.dera.gov.uk
http://sohowww.nascom.nasa.gov
http://www.ips.gov.au
http://www.spaceweather.com
http://www.sunspotcycle.com

Diver