USAFSAM Aeromedical Consultation Service Medical Risk Assessment and Airworthiness Matrix.

The 1% rule has long been a standard threshold for aerospace medical risk acceptance, but medical literature has noted multiple shortcomings with this threshold. Previous studies have suggested a risk matrix approach in aeromedical decision-making. General use of risk matrices for risk assessment is already codified in the U.S. Air Force (USAF). Based on this, the USAF School of Aerospace Medicine (USAFSAM) Aeromedical Consultation Service (ACS) generated and evaluated the ACS Medical Risk Assessment and Airworthiness Matrix (AMRAAM). The ACS adapted existing USAF standards to build the AMRAAM, gathered expert feedback, and sampled 100 previously adjudicated cases to compare legacy case dispositions to AMRAAM dispositions using polychoric correlation. The AMRAAM disposition showed strong agreement with legacy dispositions (ρ* = 0.9424). One case was discarded as it did not meet inclusion criteria. Of the 99 remaining cases, 88 had perfect agreement between legacy and AMRAAM dispositions. With the AMRAAM, eight cases were less restrictive and three were more restrictive (two due to an erroneous omission in the legacy disposition). The AMRAAM produces disposition recommendations that are highly consistent with the legacy approach informed by the 1% rule, with discordant AMRAAM dispositions tending to be more permissive. The USAFSAM AMRAAM allows a more dimensional risk evaluation than the 1% rule, communicates aeromedical risk consistent with nonmedical USAF organizations, and harmonizes aeromedical risk with the level of risk the USAF has defined for all flying systems. The ACS will use the AMRAAM as standard practice in future aeromedical risk assessments.