Radiological Protection from Cosmic Radiation in Aviation

Draft document: Radiological Protection from Cosmic Radiation in Aviation
Submitted by David Begin, IFALPA
Commenting on behalf of the organisation

General remark

In the draft the same topic is repeated in different places. Our position will be given only once to minimize doubling.

1. „Existing exposure situation“ is the wrong approach (lines 186/187)

The basic defect of the draft is defining the exposure to cosmic radiation as an existing exposure situation.
This definition stands in contradiction to ICRP 103 (6.1) as well to the European Council Directive 2013/59/EURATOM Nr. 26 and therefore a step backwards in radiation protection.
As a consequence the definition of the excludes all the procedures of flight planning in respect to radiation protection, which is already installed for example at DELTA Airlines for polar flight routes. (In forecasted space weather situations  of the NOAA SCALE S3 the DELTA dispatcher are advised not to plan routes north of 78°N and aircrew en route are advised reroute or reduce altitude to at least FL310).
Refer also to ICRP 103 (226)[1]

Replace lines 186/187 by:
For aviation the exposure to cosmic radiation is classified as a planned exposure by the commission.

The consequences of a classification as a planned exposure could be for example:

    • formation/ education of the dispatch staff in radiation protection - as far as required for flight planning

    • identification of the doses on the proposed alternative flight routes (until now, regularly alternative flight routes are proposed to the aircrew with regards to fuel and time savings, but the expected doses are not indicated).

    • establishing a system of coordinated reactions during a solar particle event
      (planning: delaying flights, route planning ; en route: rerouting, descents)

      Most of the measures already are common practice for example as reactions on volcanic ash but they have to be put in common understanding also for radiation protection.
      It is also an contradiction to the ICRP 103 to define solar particle events as existing exposures.
      If one believes in the risk studies on nuclear power reactors, a serious accident with many casualties has an probability of 10-3 to 10-4 year. The probability of a Carrington SPE or even more is some order of magnitudes higher[2]. If one considers that on average more than 100 000 persons fly in


      airplanes every hour, exposures from SPE have to be defined as emergency exposures and planning for such situations has to be established.
      Therefore we propose:
      Insert into the paper a recommendation on behalf of ICAO/IATA: How to react during a SPE (e.g. delaying flights, rerouting, coordinated descent…)

      AT comments:


      OK, Below are the definitions of ICRP of the classes of exposure for clarification. I agree that the The flight is planned exposure situation as the flight planning is done before the exposure to the radiation.


      Planned exposure situations are situations involving the deliberate introduction and operation of sources. Planned exposure situations may give rise both to exposures that are anticipated to occur (normal exposures) and to exposures that are not anticipated to occur (potential exposures; see Section 6.1.3).

      Emergency exposure situations are situations that may occur during the operation of a planned situation, or from a malicious act, or from any other unexpected situation, and require urgent action in order to avoid or reduce undesirable consequences.

      Existing exposure situations are exposure situations that already exist when a decision on control has to be taken, including prolonged exposure situations after emergencies.



      2. Misunderstanding ICRP basic principle of justification (lines 184/185)

      In our understanding the principle of justification means that the benefits outweigh the harm of the activity. With regards optimization and dose limitation of the individual a protection strategy has to be developed and implemented.
      Therefore establishing a protection strategy is not a question of justification! If a exposure situation is justified, the implementation of a protection strategy has to be implemented. There is no alternative.


      3. Set the dose constraint to 6mSv/year (lines 194-196)

      Dose reference levels are only applicable in existing or emergency exposures but not in planned exposures. If one seriously wants to apply the ALARA principle, a dose constraint of 6mSv/year is justified and practical experience, as it is proven by the German Dose register. (Cf. Footnote 2)

      Therefore replace lines 194-196 by:
      … as reasonably achievable (ALARA) with a dose constraint level below 6mSv/year.

      AT: Agree, even though IFALPA position states that “IFALPA recognizes 20mSv as the annual limit for occupational exposure for aircrews as established by the ICRP in recommendation 103 (2007)

      The 6 mSv limit has been used in many national regulations already.



      4. Education and information of all persons involved in planning and carrying out flights (lines 218/219)

      The exposure of aircraft crew and passengers during a real flight depends at first on flight planning. Therefore not only the crew but also the dispatching staff have to be educated in radiation protection through courses and educational programs (CBT etc).
      On the individual flight plan the expected dose has to be stated.

      Therefore replace lines 218-219 by:

      (i) Educate the dispatching personnel and aircrew in radiation protection through initial courses and recurrent programs (computer based training).


      5. Assessing the doses (lines 220/221)

      ICAO Annex 6 Part I - Operation of Aircraft - (November 2010) requires :
      6.12 All aeroplanes operated above 15 000 m (49 000 ft) — radiation indicator
      All aeroplanes intended to be operated above 15 000 m (49 000 ft) shall carry equipment to measure and indicate continuously the dose rate of total cosmic radiation being received (i.e. the total of ionizing and neutron radiation of galactic and solar origin) and the cumulative dose on each flight. The display unit of the equipment shall be readily visible to a flight crew member.
      Note.— The equipment is calibrated on the basis of assumptions acceptable to the appropriate national authorities.

      As handy dosimeters (even TEPCs) have been developed, the International Federation of Airline Pilots Associations requires:
      Therefore aircraft with a maximum operational altitude of more than 8,000m (approx. 26,000ft) operating in polar / sub-polar regions should be equipped with active dose measuring devices. During flight, the cockpit crew should have the display of the dose rate and accumulated flight exposure plainly visible.

      Therefore replace lines 220/221 by:
      (iii) Assess the dose of each flight using dedicated calculation programs; when available, aircraft with a maximum operational altitude of more than 8000m (approx. 26 000ft) shall be equipped with active dose measuring devices.


      6. These data should be … kept for sufficient time (lines 223/224)

      The term „sufficient time“ has to be specified in more detail. The swiss dose register keeps doses for 100 years. Regarding epidemiological studies but also individual medical histories the storing time should assume the swiss regulation.



7. Adjusting the flight roster (lines 225-227)

Adjusting the flight roster is one instrument of optimization. Therefore the optimization of the roster shall not be left to the operation management’s discretion.
Therefore replace lines 225-227 by:
(v) In order to respect the dose constraint, the operator management shall in coordination with the concerned crew member adjust the flight roster.


8. SEP: retrospective dose calculation is NOT the only means of protection! (lines 554-558)

Except for research and high-altitude aircraft (IACO Annex 6 Nr. 6.12) there are no dosemeters on board of aircraft. As already stated (Nr. 6 Lines 220/221), there is a need of on-board measuring devices in order to lower the exposure during a SPE. Even if those instruments do not measure the correct absolute value, they can indicate unusual increases in dose rate. Consequently there is no need to display exact figures, it is sufficient to give off a warning (“red light“) if the dose rate exceeds a certain threshold. (cf. Matthiä, D. et al, Mitigation Measures during a GLE, J. Space Weather Space Clim. , 5 , A17 (2015))
Therefore in line 555 insert before „The calculation…“:
Measuring devices indicating an SPE should be installed in aircraft with operational altitudes above 8000m flying in subpolar and polar regions to mitigate the exposure.


9. Lightning and TGF are not unknown phenomena (lines 567-579)

The statements concerning TGF are quite superficial. Measurements of lightnings on board of an Airbus A350 exist and the theory is also very developed. On average an aircraft is struck by lightning every 1000 flight hours (Boeing Aero Magazine QTR_4/12, which means that a pilot averages one lightning strike per year. Apparently the task group did not take  flights through the ITC into account where during a lightning strike aircrew are exposed up to 30mSv (this being the most optimistic calculation).
We propose at least to replace line 576 and further:
These phenomena of atmospheric high energy rays are potentially an additional hazard. Therefore the commission appreciates the intensive research and development on these topics currently underway. As soon as reliable results are available the commission will take action.



10. Standard flight profile is not at all representative concerning radiation exposure (lines 559/558 and lines 614/615)

Wrong! Standard flight profiles refer to great circle routes and standard altitudes. If the „optimum flight level“ is flown, exposure increases already by about 25%. Furthermore a deviation of the geographic longitudes and latitudes can change the exposure in a significant manner (cf. Dyer et al.; The QinetiQ Atmospheric Radiation Model and Solar Particle Events; 3rd European Space Weather Week, Brussels 2006) (cf. comment Nr.6)
Therefore replace line 614-616 by:
… the commission recommends the use of validated computer codes and active dose measuring devices for aircraft with a maximum operational altitude of more than 8000m (approx. 26 000ft) to monitor individual exposure in aviation.



11. Existing exposure is in contradiction to ALARA (line 744/745) (cf. comment 1)

(40) The commission regards human exposures in aviation resulting from cosmic radiation as a PLANNED exposure situation.


12.The position of the task group does not reflect the best practises already now in use (lines 886-897) In solar particle situations greater than „NOAA S2“ US Airlines reroute polar flights and decrease flight altitudes (FL<310) (cf. Fahey T. , Scott G.; Hazard Avoidance Procedures &Use of Space Weather Information; Weather Workshop Aviation & Space Weather Session, 2012 Boulder, CO). Increased fuel consumption and time delay are not significant (e.g. Matthiä, D. et al.; Economic Impact and Effectiveness of Radiation Protection Measures in Aviation during a GLE; Space Weather Workshop, 2015, Boulder, CO: „No delay, +2.4% fuel, 27% reduction in total Effective Dose (58% of SEP“).
These lines have to be revised completely, taking the status of the standard procedures of the airline industry and with an recommendation to ICAO/IATA to recognize the industry’s standards as official standards.

13. Calculate/ measure each flight individually (lines 966/967)

As already stated (cf. comment 11) „typical effective dose rates“ are not appropriate because the exposure at real flight profiles and flight routes is usually misrepresented by „a standard flight profile“. As the crew complement typically changes on every trip, the annual exposure of a crew member cannot be derived by an „annual aircrew dose“.
Therefore replace lines 966/967 by:
Like for any occupationally exposed worker, the commission recommends the effective dose of each aircraft crew member be assessed. The effective dose can be derived from dedicated measurements or computer codes.



14. Information of aircrew is a duty of the employer (lines 973/974)

The wording may encourage airline to conceal this information. As the airline is normally the only recipient of the exposure data concerning the health of the individual, it shall be mandatory to forward this information to the individual.
Therefore line 973 shall be revised by:
…, and the individual doses should be made available to the individual.


15. There is a basic misunderstanding: The crew complement is not fixed, it changes on every trip (lines 981-983)

For safety reasons the crew complement is assigned anew for every trip. Thus the flight crew scheduling has to monitor the exposure of each individual.
Therefore replace lines 981-983 by:
(60) In order to respect the dose constraint, the operation management shall adjust the roster of individual concerned individual (frequency and destination).


Dr. Antti Tuori

IFALPA Human Performance Committee, Vice Chair



[1]The difference in terminology between planned and other exposure situations (emergency and existing)

has been retained by the Commission to express the fact that, in planned situations,

the restriction on individual doses can be applied at the planning stage,and the doses can be forecast so as to ensure that the constraint will not beexceeded.

[2] cf. EURADOS WG 11