No abstract

Air carrier crews are occupationally exposed to ionizing radiation, principally from galactic cosmic radiation. To promote radiation safety in aviation the Federal Aviation Administration has: issued educational material on the nature of the radiation received during air travel; recommended radiation exposure limits for pregnant and nonpregnant aircrew members; developed computer programs that estimate for a given flight profile the amount of galactic radiation received on a current flight or on one flown at any time back to January 1958; published tables that enable aircrew members to estimate possible health risks associated with their occupational exposure to radiation; and conducted research on effects of radiation during pregnancy. References for this material are given in the article. In addition, graphic and tabular data in the article show how galactic radiation levels and the composition of the galactic radiation has changed between 1958 and 1999. Also given are estimates of effective doses received by air travelers on a wide variety of air carrier flights.

Air safety is tied to the phenomenon of ionizing radiation from space weather, primarily from galactic cosmic rays but also from solar energetic particles. A global framework for addressing radiation issues in this environment has been constructed, but more must be done at international and national levels. Health consequences from atmospheric radiation exposure are likely to exist. In addition, severe solar radiation events may cause economic consequences in the international aviation community due to exposure limits being reached by some crew members. Impacts from a radiation environment upon avionics from high-energy particles and low-energy, thermalized neutrons are now recognized as an area of active interest. A broad community recognizes that there are a number of mitigation paths that can be taken relative to the human tissue and avionics exposure risks. These include developing active monitoring and measurement programs as well as improving scientific modeling capabilities that can eventually be turned into operations. A number of roadblocks to risk mitigation still exist, such as effective pilot training programs as well as monitoring, measuring, and regulatory measures. An active international effort toward observing the weather of atmospheric radiation must occur to make progress in mitigating radiation exposure risks. Stakeholders in this process include standard-making bodies, scientific organizations, regulatory organizations, air traffic management systems, aircraft owners and operators, pilots and crew, and even the public. Aviation Radiation Is an Unavoidable Space Weather PhenomenonAir safety has improved significantly in many meteorological areas over the past decades with the exception of space weather, which includes ionizing radiation. While a framework for addressing radiation issues has been constructed, we believe that more can and must be done at international and national levels. In particular, measurement programs must be expanded and linked with models to provide current epoch and, eventually, forecast information for the aviation ionizing radiation environment. A diverse radiation measurement and modeling community exists with a strong interest in improving international air safety.There are two challenges in our ever more mobile, technologically dependent global society. First, pilots, crew, and passengers, which include fetuses between their first and second trimesters, might face additional radiation hazards in terms of dose equivalent rate (rate of absorbed dose multiplied by the quality factor), particularly when flying at commercial aviation altitudes above 26,000 ft. (7924.8 m) (8 km) (see Figure 1). Second, avionics can experience single event effects (SEEs) from both the ambient high-energy and thermal neutron environments. The source of this radiation in either case is twofold-from the continuous bombardment by primary background galactic cosmic rays (GCRs) and also from solar energetic particles (SEPs) emitted during occasional solar flare events lasting up to a ...

Aircrew members can be exposed to higher annual doses of natural ionizing radiation than members of the general population in most parts of the world. The principal ionizing radiation to which they are exposed is galactic cosmic radiation (GCR). Among the particles present in the primary spectrum are heavy ions: relativistic nuclei of lithium and heavier elements. These ions have very high radiation weighting factors and can contribute significantly to the effective dose at altitudes above the Pfotzer maximum. This report describes the latest version of the US Federal Aviation Administration's GCR flight dose calculation software, CARI-7A. Unlike its predecessor, CARI-6, CARI-7A directly includes heavy ion transport, using a database of atmospheric particle spectra generated by incident GCR ions pre-calculated with MCNPX 2.7.0. to enable calculations to the edge of space. Results are compared with measurements aboard commercial passenger aircraft, high altitude research aircraft and similar calculations by others.