Primary Scope - The FAA seeks to move away from prescriptive-based standards to more physiologically relevant, performance-based standards such as an SpO2 range to better describe aircraft passenger safety in addition to providing an easier template for oxygen systems manufacturers in which to abide. Furthermore, the FAA seeks to re-evaluate volume of oxygen flow (L/min) necessary to maintain passengers’ blood oxygen saturation levels. Secondary Scope - This research will investigate altitudes up to 45,000 feet for reasons that 14 CFR Section 25.841 currently limits altitude to 40,000 feet. Several airplane manufacturers have strong claims and are seeking exemptions for operations above 40,000 feet based upon airframe improvements and subsequent significant minimization of the potential for decompression events, i.e.) rear mounted engines for which an uncontained failure will not amount to fan-blade piercing of the passenger cabin bulkhead. Amendment 25-84 revised the “pressurized cabin” airworthiness standards for subsonic transport airplanes with 3 new requirements governing cockpit/cabin environment: - 25.841 (a)(2)(i) – Cabin pressure not to exceed 25,000 feet for more than two minutes - 25.841 (a)(2)(ii)- Cabin pressure not to exceed 40,000 feet for any time - 25.841 (a)(3) - Fuselage, structure, engine and system failures are to be considered in evaluating the decompression Potential for Highest Beneficial Outcomes – Scientific data currently moderately supports FAA Rule-Making with focus upon passenger supplemental oxygen availability and delivery as stipulated by current FAA regulations and/or associated documents. This OFOS project is expected to produce data, analyses, and discussion that may justify moving forward with said rule-making effort. Positive findings in regards to the primary and/or secondary scope listed above will be weighed through FAA committee. Benefits of this research are to add to the collective scientifically-founded momentum to justify a rule-making session that favors use of empirical physiological data independent variables, such as are employed in the OFOS protocol, in lieu of engineering/mechanistic/computer science calculations of oxygen supply adequacy that are currently used and required by FAA doctrine. As a result, current and future oxygen system technologies will experience less restrictive certification regimes. A safer goal of human oxygenation outcomes will then be the appropriate focus rather than expected or calculated safe levels of oxygen inputs regardless of the resulting human condition.