Radiological Protection from Cosmic Radiation in Aviation

Draft document: Radiological Protection from Cosmic Radiation in Aviation
Submitted by Theresia Eberbach, Vereinigung Cockpit e.V. -German Airline Pilots' Association-
Commenting on behalf of the organisation

RADIological Protection from Cosmic Radiation PROTECTION IN AVIATION

Comments of Vereinigung Cockpit
- German Airline Pilots' Association -


General remarks

In the draft the same topic is repeated in different places. Our position will be given only once to minimize doubling.
If the Task Group wishes, the Radiation Protection Committee of Vereinigung Cockpit expresses its willingness to explain and discuss its position during a meeting.

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 is therefore a step backwards in radiation protection.
As a consequence the definition of „existing exposure“ 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 above NOAA SCALE S2 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 )[1].  Refer also to ICRP 103 (226) [2] 

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 less than 10-3 to 10-4 per year. The probability of a Carrington SPE or even more is some order of magnitudes higher [3]. 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…)


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 to 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 6 mSv/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. [2])

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


4. Classify frequent flyers for duties (couriers) as occupationally exposed persons (lines 210-215)

Couriers often fly more frequently than „normal aircrew“. Therefore the case-by-case basis by a voluntary agreement is not appropriate. The status of the couriers has to be declared as occupationally exposed persons.

Therefore replace lines 210-215 by:
For the fraction of frequent flyers for professional duties of which exposures are comparable to those of aircraft crew, the Commission recommends that they are classified as occupationally exposed persons.


5. 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).

(ii) In the flight plan the expected doses shall be stated.


6. 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 / subpolar 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. 


7. 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.


8. 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 operation management shall - in coordination with the concerned crew member - adjust the flight roster.
By the way the present text of the draft already is in contradiction to "existing exposure", because the operation management is capable to plan the exposure of the aircrew. This contradiction can be disbanded by classifying the exposure of aircrews as "planned exposure".


9. 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.[4]
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.


10. 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 [5]. On average an aircraft is struck by lightning every 1000 flight hours [6] , 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.

11. 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 [7].  (See also our comment Nr.6)
Therefore replace line 614-616 by:
… the commission recommends the use of validated computer codes and - when available - active dose measuring devices for aircraft with a maximum operational altitude of more than 8000m (approx. 26 000ft) to monitor individual exposure in aviation.


12. 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.


13. The position of the task group is not in line the standard procedures of the airline industry (lines 886-897)

In solar particle situations greater than „NOAA S2“ US Airlines reroute polar flights and decrease flight altitudes (FL<310) [8]. Increased fuel consumption and time delay are not significant [9] .
These lines have to 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.

14. Lines 955-958 cf comment Nr. 4

As already stated.

15. 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.

16. 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.


17. The class 1 medical is not at all equivalent to the „Radiation Medical“ (lines 976-980)

Even though aircrew undergo regular medical examination, the task is limited to assessing a crew member either fit or unfit to fly. The scope is not directed towards long term health effects but to check the ability to fulfill their duty until the next examination.

Furthermore - since crew members are typically concerned to lose their medical if a certain condition becomes known - the dialogue between examiner and worker is often limited to the exact scope of the examination (sometimes even by law).

Therefore replace lines 976-980 by:

Aircrew undergo regular medical examination assessing them to be „fit“ or „unfit to fly“ for the validity period of the certificate. The scope is consequently not directed towards long term health effects and therefore cannot adequately replace specific medical examination regarding radiation exposure.

18. 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 the concerned individual (frequency and destination).

By the way: If the position "existing exposure" of the Task Group would be maintained and not changed in "planned exposure" the  paper would be inherently contradictory.

19. „Women who ... may be or expect to be pregnant“ = Women younger than 50 years (lines 997-999)

As a measure of antidiscrimination and practicability, all women who fly frequently should be informed.
Therefore replace lines 997-999 by:
Women who fly frequently shall be provided with sufficient information to make informed judgments regarding the flight schedule and any adjustment they have to consider necessary.



Literature and Remarks

[1] Fahey T. , Scott G.; Hazard Avoidance Procedures &Use of Space Weather Information; Weather Workshop Aviation & Space Weather Session 24 April 2012 Boulder, CO;


[2] 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 be exceeded.


[3] cf. EURADOS WG 11 Meeting, Paris, 28-29. September 2015

[4] Matthiä, D. et al, Mitigation Measures during a GLE, J. Space Weather Space Clim. , 5 , A17 (2015)


[5] Kochkin,P. et al. In-flight measurements of energetic radiation from lightning and thunderclouds, Journal of Physics D: Applied Physics, Vol 48  ( 2015) Nr. 42 


[6] Boeing Aero Magazine QTR_4/12


[7] Dyer et al.; The QinetiQ Atmospheric Radiation Model and Solar Particle Events;
3rd European Space Weather      Week, Brussels 2006


[8] Fahey T. , Scott G.; Hazard Avoidance Procedures &Use of Space Weather Information; Weather Workshop  Aviation & Space Weather Session, 2012 Boulder, CO


[9] 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“


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