A Systems Engineering Approach to Identifying Technology to Improve Terminal Area Performance in Future Air Vehicles

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The Environmentally Responsible Aviation (ERA) Project within NASA’s Aeronautics Research Mission Directorate (ARMD) has identified metrics, goals, and objectives (MGOs) associated with noise, emission and fuel consumption of future air transport vehicles. As the ERA project progresses and lays the path to mature new technology, it becomes important to decompose these MGOs into aircraft performance requirements for which technology can be identified and worked to establish that level of performance, and achieve a Technology Readiness Level (TRL) of 6 appropriate for flying a new aircraft in a relevant environment. Optimizing the performance of the ERA aircraft during the take-off, climb, transition, descent and landing phases, what are being called, “Terminal Area Operations”, is not the primary objective of the ERA project since the majority of the mission takes place during the en route or cruise phase. Due to this, optimizing requirements such as cruise drag and fuel consumption become crucial to meeting the ERA MGOs and will require a significant effort. However, the performance requirements in the terminal area phases still need to be considered. The terminal phases comprise merely 5% 10% of the entire mission but are critical to its overall success; a safe and efficient take-off, transition, and landing are mandatory for every flight. Therefore, it is understood that in the terminal area phases it may be necessary to accept trade-offs such as using a flap/high-lift system to fly slower and accept a higher level of drag or fuel consumption in order to assure a safer take-off and landing. Or, as another example, a minimum acceptable climb rate needed for operations in the congested terminal airspace may not be optimal compared to the minimum fuel burn climb rate the cruise-optimized design suggests. Lastly, there are community noise and landing and take-off (LTO) nitrous oxide pollution emissions MGOs for ERA that are directly impacted by terminal area performance. The community noise mitigation operations at Santa Ana / Orange County airport are examples of employing unusual operational procedures to reduce some of the perceived noise levels on the ground with the corresponding increase in fuel consumption and operational complexity compared to a standard take-off. Without an obvious set of dominant MGOs, determining the performance requirements and corresponding research priorities for terminal area operations become an exercise in systems engineering. In order to establish those priorities, a team of subject matter experts (SME) met at NASA Ames Research Center in Feb 2011. For 1 1⁄2 days the team met, discussed, and evaluated how terminal area performance criteria might have an impact on the ERA MGOs. A Quality Function Deployment (QFD) was used by the team to aid in the analysis as was a “brainernet” discussion. The SMEs also discussed some candidate technologies that have the potential to either improve the ERA performance, or at least, mitigate the “off-design” performance associated with flying in the terminal airspace. This paper explains the QFD process used, and examines some of these performance requirements, and how they might impact the ERA MGOs. It will also present some candidate technologies that were determined by the SMEs as potential to address significant terminal area performance issues and still meet the ERA MGOs.