Radiological Protection from Cosmic Radiation in Aviation

Draft document: Radiological Protection from Cosmic Radiation in Aviation
Submitted by Capatin Michael Holland, Allied Pilots Association
Commenting as an individual

Paragraph 5. Line 408,

Many unknowns exist for crew exposure. Had an effort been undertaken to run a personal dosimetry program for some sample of individual crewmembers we might have some perspective on the Gamma exposure from thunderstorms. The ICRP cites limits on flying time as a justification for not recommending personal dosimetry. In the United States contractual limits on flying time are a thing of past. For pilots the FAA 1000 hour annual limit still exists but flight attendants have no limits and many fly over 100 hours each month, these professionals make up the majority of the exposed population. In addition it is fairly common for crewmembers to commute to work via air travel (due to industry consolidation) adding to their exposures. In addition, in the United States pilot mandatory retirement age is now 65 years of age adding an additional 5 years of exposure since ICRP last published it opinion. Today’s aircraft are flying longer legs at higher altitudes increasing exposures. The conversion of commuter aircraft from turboprop to jets (with the associated increase in cruise altitude) has led to increased exposures of crewmembers at younger ages.  An individual dosimetry project is needed to support this assumption by the ICRP.

Paragraph 20. Line 564

This is an assumption also without any support of direct measurement of human exposure. Modeled data has value. Modeled data as the sole source for human exposure measurement is not an acceptable solution.  

Paragraphs  23 & 25

In the United States the FAA has obtained some data for verification of the CARI exposure model. The FAA presents this model as a method to compute Galactic exposures for crewmembers. The FAA conducts no regular verification of its model even though this model is presented as a means for a crewmember to compute Galactic exposure. Most crewmembers do not have access to the data (principally altitude) necessary to effectively make the required inputs. In my 35 years of military and commercial employment as a pilot I have never encountered any United States crewmember who had his or her exposure computed and tracked. The largest aviation industry in the world has no crewmember radiation regulations or mandatory education for its crewmembers about their exposures. The ICRP is correct in its recommendation for monitoring of crew exposures given the relatively large exposures involved but that perspective is lost for crewmembers working in the United States.

Paragraph 28

For crewmembers flying in the United States and Canada the configuration of the Earths geomagnetic field results in higher exposures.  This paragraph focuses on European exposures, the United States has the largest population of exposed individuals.

Paragraph 34 Line 698

The reference to light skin and sunbathing  is qualified here using the word apparently. I have heard this before but have never been able to track this statement to its source. To be included here this statement needs to include reproducible  studies comparing the overall population sunbathing habits to those of crewmembers. I have never seen a study that identifies the crewmember population as exhibiting a larger proportion of light skinned individuals. If this opinion can be verified those reproducible studies should be included. In the United States the length of layovers for crew members is often much too short for “sunbathing”.  Care must be exercised when examining this issue to recognize the fact that in the United States the proportion of flying done by the long haul international community (with longer layovers requiring 2 sleep cycles) is dwarfed by the domestic flying community. If the ICRP has useful references they should be included or these statements should be dropped.


Paragraph 34 Line 702

No mention is made here that pilots are in part selected and retained by virtue of their good health. The requirement to remain healthy and pass a flight physical throughout a career puts pilots in a special category. For a pilot this often requires more frequent use of medical services which often leads to better than average health. This healthy population effect must be recognized and the statistical handling of the associated data must be carefully analyzed.


Paragraph 55

Currently in the United States the data necessary to conduct airline flights depends on communicating weather information to the responsible parties. Pilots, dispatchers, air traffic control, etc. are all included in the dissemination of weather data. I can request while in my seat the weather for any airport and have that data in minutes. During a Ground Level Event I have no access to the relevant data while airborne. Since the delivery methods for weather data already exist and space weather information is free from the National Weather Service it is only a programing exercise to make the data available to the pilot. Interestingly, your grandmother in a seat behind me can log on to the internet and have access to that data. Pilots will exercise their judgement to determine the correct action to take and would never put a flight at risk. I make many requests for changes in altitude each week for many differing reasons. Altitude change is a routinely requested and often exercised practice. Air traffic control may see an increased work load but by your own statements a GLE is a rare event.  Due to the rarity of these events the increased fuel burn from lower altitude flight would also occur rarely. As pilots we deal with the risks inherent in aviation every moment of every flight. I constantly balance these risks. My passengers, my company and the FAA expect me to protect my passengers to the best of my ability from the risks inherent in aviation. Radiation is one of those risks but if I must have good information to make good decisions.

Paragraph 64

Given that aircrew are on average one of the most highly exposed if not the most highly exposed to radiation the ICRP should strengthen its training recommendations.  The training materials furnished by the FAA are written for an audience that has an understanding of radiation. Most of those affected do not have the scientific education necessary to understand what is provided. The principal of informed consent is dependent on the employee being trained and understanding the risk. The understanding  of that risk in the United States is lacking due to the absence of education of crew. Given the high exposures a career airline pilot will receive every basic flying text should educate the prospective pilot about this exposure. An individuals genetic sensitivity to cancer is best handled by the individual making an informed decision.

Section 4.3

In the United States the FAA recommends that the employee work with her employer to protect the fetus. It is common for US flight attendants to be pressured to work while pregnant. The lack of education sbout the risk to the fetus prevents a meaningful discussion between airline management and the employee and puts the employee at a decided disadvantage. Training of both airline management and the prospective mother are lacking in this area.


In summary

I am grateful that the ICRP is updating its guidance for aircrew. The ICRP must recognize that the largest airline industry in the world has not adopted its recommendations and must look to target the US audience as well.

Respectfully submitted,

Captain Michael Holland