In September, BeCA and the Federal Agency for Nuclear Control (FANC, https://fanc.fgov.be) designed a survey aimed at all pilots and crew members flying in Belgium. The survey aimed to get an overview of how well crews are informed by their airline on their annually received dose of cosmic radiation. The survey collected over 300 responses, giving a pretty good idea of the problem.

The good news is: 96% of the respondents are aware that they are exposed to cosmic radiation. Unfortunately, it seems that most flight crews are not or insufficiently informed by their airline on the doses they receive each year. Sometimes, the information is available, but difficult to find or available only on request, sometimes crews don’t even know if it’s available. Only 10% of the respondents think cosmic radiation levels are taken into account in their rosters, while 53% doesn’t know and the rest believes they are not considered at all. Looking at the free text comments, it is clear that pilots not only want to be more informed about the dosage they receive, but also about the potential consequences; they feel that airlines do not take this issue seriously; and several respondents even suggest that pilots should have a radiation level meter on them when flying.

BeCA wishes to thank all of you who took the time to respond to this survey and will meet with FANC to perform a more detailed analysis and consider what should be done at national and/or airline level. We will of course keep you posted once we have more information! Meanwhile, have a look at our FAQs about Cosmic Radiation and its effects on YOUR health.

Why do we speak of radiation in commercial aviation?

Flight crews are considered as radiation occupational workers. Unlike workers in nuclear power plants or hospitals we are not dealing with radioactive materials but we are exposed to natural radiation sources (e.g. Radon).
What is the origin of radiation source for flight crews?

Cosmic radiation comes from high energy particles (protons, neutrons, electrons and others) traveling through space at very high speeds (close to the speed of light).

Sources of radiation

• Galactic radiation
  It’s produced by galactic events like Super Novae (dying stars), black holes (Hawking radiation) and so on. This source provides an almost constant level of radiation to the earth all year round, day and night.
• The Sun
  The second source comes from the biggest natural nuclear power plant in our solar system: our Sun.
  As the sun is relatively close to earth, we are very dependent on its activity (solar weather) with regards to the radiation doses it produces.
  The doses generated by the sun can reach very high levels, very quickly during a solar event (e.g. solar storm).
• On the ground
  Even at ground level we receive doses of cosmic radiation and other natural radioactive sources (e.g. Radon).

What is the problem with cosmic radiation?

Cosmic radiation would threaten life on earth if nature wouldn’t have provided us with two shields: the Earth’s atmosphere and the Earth’s magnetic field.

So the higher we fly, the less atmosphere we have above us as a protection; and the closer to the poles, the lesser the protection from the magnetic field (plus, the layer of atmosphere is thinner there).

When an atomic particle collides with a human cell here is what might happen:

• Level 1: the particle passes through without causing any damage.
• Level 2: the particle damages the cell and causes it to die, a new cell will grow and  replace it, without lasting damage.
• Level 3: the particle hits the strands of DNA located in the nucleus of the cell and breaks them, which might change the DNA sequence and cause a mutation (potential cancerous growth, damaged DNA transmitted to newborn childs, etc.).

The human body is designed to cope with some exposure to cosmic radiation like we receive on the surface but overexposure can lead to potential cancers (like blood cancer, brain cancer, breast cancer, prostate cancer, etc.).

What about the equipment?

While we’ve discussed the consequences on the human body, it needs to be highlighted as well that those kinds of radiation can damage aircraft equipment resulting in an increase of technical problems. Since we are using more and more sophisticated and sensitive equipment this is a real hazard in today’s and future operations.

To address that issue the European Space Agency (ESA) is developing a tool that would provide space weather information to the pilots and flight operation of the airlines (similar to what we have for volcanic ash), another project where BeCA in collaboration with the Royal Belgian Institute for Space Aeronomy (www.aeronomie.be) is involved in.

How is information on the radiation dose provided to the crews?

Relatively cheap and basic computation software can be used and is available on the web (like the FAA’s CARI program). However, those tools assume that the radiation levels remain constant over a period of a full month (an average value is computed).
However from time to time, bursts of particles generated by solar flares can increase radiation values up to 50 or even 100 times above their normal levels.

That’s why more elaborated software needs to be used additionally taking into account the actual flight profile flown. These could be corrected even further using either on board or ground-based measurement equipment resulting in very accurate values which could be made available to crews in 1 to 3 months (time needed for measurements and computation).

What does the law say?

The European council Directive 96/29/Euratom  (http://bit.ly/2pWsXno) sets the basic safety standards for the protection of workers from cosmic radiation.
This was implemented in Belgium through a Royal Decree in 2001 under the governance of FANC (Federal Agency for Nuclear Control).

When a worker is likely to reach 1 millisievert (1 mSV) per year, the law requires to:

• assess the exposure of the crew concerned.
• take into account this assessment to organise work schedules (eventually reducing the dose of highly exposed crews)
• inform the worker and company occupational doctor of the health risks involved by the work.
• limit the doses in case of pregnancy as low as reasonably achievable, never exceeding 1mSv/year.

In the latest version of the law, FANC added the following requirement:

• The introduction of a radiation protection officer, approved by FANC who has at least basic knowledge of cosmic radiation.

BeCA also calls for the addition of quality criteria for dose calculation codes.

What are the radiation limits?

• Up to 1mSv/year all of the above requirements apply i.e. monitoring.
• Between 1mSv and 6mSv per year, monitoring should be complemented by mitigation measures to avoid reaching the 6mSv limit.
• Above 6mSv per year, a medical follow-up is mandatory and the worker’s doses and medical records needs to be stored until the worker attains the age of 75 and not less than 30 years after the termination of the work.
• The maximum legal dose for radiation workers is 20mSv per year, but you are unlikely to reach this limit unless you are victim of a nuclear disaster like Fukushima.