Every number on a FlightRadiation report is produced by running the flight through the FAA CARI-7 / CARI-7A cosmic-radiation transport model and weighting the output with ICRP Publication 103 tissue weighting factors. This page documents the model, the inputs, the derived metrics, and the uncertainty bounds.
CARI-7 is the seventh-generation cosmic-radiation transport code published by the FAA's Civil Aerospace Medical Institute (CAMI) in Oklahoma City. It replaced CARI-6, which had been the regulatory reference since the late 1990s. CARI-7 differs from CARI-6 in that it uses Monte Carlo particle transport (MCNPX-based) and includes secondary particle production (neutrons, muons, electromagnetic cascade) explicitly rather than via tabulated parameterisation.
The publicly maintained interactive version, CARI-7A, accepts origin and destination airports (IATA or ICAO), a cruise flight level, departure date, and aircraft type. It returns effective dose for that single flight in microsieverts. We compute the single-flight dose from the same physics tables and great-circle routing logic documented in Copeland's CARI-7 / CARI-7A documentation (see sources), then wrap it in plain-language context.
The CARI series outputs effective dose, denoted E, in sieverts. Effective dose is not a measurement; it is a calculated whole-body equivalent that accounts for (a) the radiation type's biological effectiveness via radiation weighting factor wR, and (b) the differential radio-sensitivity of organs via tissue weighting factor wT. We use ICRP Publication 103 (2007) wT values, which superseded ICRP Publication 60 (1990).
The key ICRP-103 wT revisions from ICRP-60: gonads dropped from 0.20 to 0.08, breast rose from 0.05 to 0.12, brain raised explicitly to 0.01 (was in the remainder under ICRP-60). For typical cruise altitudes and mixed cosmic-ray fields, ICRP-103 weighting yields E values within roughly 10–15% of ICRP-60 weighting for the same physical fluence, but the direction of the correction depends on the radiation field composition. We always cite ICRP-103.
The whole form is one flight, with no account to create.
The PDF contains the following derived quantities, each computed as documented below:
| Metric | How we compute it |
|---|---|
| Single-flight effective dose (µSv) | CARI-7 output for the route (O/D great circle) at the entered cruise altitude, integrated over the flight time. Round-trip is twice the one-way figure. |
| Everyday comparisons | The flight dose placed against a chest X-ray (~100 µSv), a dental bitewing (~5 µSv), and a year of US natural background (~3 mSv), from ICRP and NCRP-184 reference tables. |
| Annualised dose (if a frequency is given) | Single-flight dose × times-per-year. Reported in mSv and placed against the ICRP-103 public reference level of 1 mSv/yr. |
| ICRP-103 reference-level comparisons | The flight (and annualised total, if given) against (a) ICRP-103 public 1 mSv/yr, (b) pregnancy 1 mSv across gestation, (c) FAA aircrew action level 6 mSv/yr (NCRP Report 132 / FAA AC 120-61B), (d) ICRP-103 occupational 5-yr averaged 20 mSv/yr. |
| Pregnancy note | For a pregnant traveller: the flight and any annualised total compared against the ICRP-103 fetus reference of 1 mSv across the remainder of pregnancy (ICRP-103 §5.4.2), with a pointer to consult an obstetrician (ACOG Committee Opinion 656). |
The CARI series has been validated against a large set of in-flight neutron and ionising-radiation measurements (Friedberg & Copeland and colleagues, multiple decades of papers; see sources). The model's stated uncertainty for galactic cosmic-ray-driven effective dose at typical cruise altitudes is on the order of ±25% (2σ) when compared to instrumented measurements. We carry this band through the report: a value of "5.4 mSv/yr" should be read as "approximately 4 to 7 mSv/yr at the 2σ level". The polar-route attribution metric is less precise because the geomagnetic-cutoff transition is gradual rather than a hard 60° step, but the qualitative finding (polar segments dominate transatlantic dose) holds across implementations.
The CARI-7A heliocentric-potential tables are updated by FAA CAMI as new neutron-monitor data become available. We pull the latest published tables monthly. The ICRP-103 weighting factors are static; ICRP-103 has been the operative recommendation since 2007 and a successor publication is not yet in force. NCRP Report 160 background-dose values reflect 2006 US-population averages and have not been formally superseded.
Every report PDF lists the exact CARI-7A version used, the heliocentric potential table month, and the ICRP-103 wT set. A reader with access to the public CARI-7A web tool can reproduce every per-segment number on the report.
FlightRadiation reports are an educational dose estimate. They are not a medical diagnosis, an occupational dosimetry record for regulatory purposes, or a substitute for an employer's dosimetry program. We are not affiliated with the FAA, ICRP, NCRP, NOAA or any other agency. If your work or health situation depends on a certified dose record, consult your employer's radiation-safety officer or an occupational-medicine physician.
Last reviewed 30 June 2026 · See our sources