NextGenerationNASAGAAdvancedConceptAndrew S. HahnNASA Langley Research CenterABSTRACTNot only is the common dream of frequent personal flighttravel going unfulfilled, the current generation of GeneralAviation (GA) is facing tremendous challenges thatthreaten to relegate the Single Engine Piston (SEP)aircraft market to a footnote in the history of U.S. aviation.A case is made that this crisis stems from a generally lowutility coupled to a high cost that makes the SEP aircraftof relatively low transportation value and beyond themeans of many. The roots of this low value are examinedin a broad sense, and a NextGenerationNASAAdvancedGAConcept is presented that attacks thoseelements addressable by synergistic aircraft design.this aggregate result implies that there is a fundamentallimit on how much time most people are willing to spendin daily travel, and is approximately 1.25 hours.INTRODUCTIONIn order to understand where the SEP GA aircraft fits in tothe transportation system and its future potential, oneneeds to examine the fundamental demand fortransportation and the elements that constrain thetraveler’s choices. Also, the concept of transportationvalue is examined in narrow performance terms andexpanded to include broader considerations. Finally,those value considerations that are addressable throughsynergistic aircraft design are identified and approachedwith a specific demonstrator concept vehicle.TRANSPORTATION DEMANDThe ability to travel is one of the most basic humanneeds. The more travel made possible, the greater thesocioeconomic opportunities available. Schafer reportsthat the ability of an individual to travel is constrainedprimarily by two budgets, time and money, and that theaggregate behavior of people can be largely explainedby the average budgets of groups . Although notcompletely separable because of land use specifics, itappears that demand for travel is mostly constrained bythe time budget and that travel mode choice is mostlyconstrained by the money budget.TIME BUDGET - Figure 1 indicates that the average timebudget available for daily travel appears to be relativelystable across income levels and cultures . Althoughthere is obviously large variation between individuals,Figure 1 – Daily Travel Time BudgetThis appears to be the result of most people leadingsimilar lives, with the bulk of the day spent sleeping andworking, leaving about the same amount of time for therest of life. By measuring the travel budget in time,instead of distance, the characteristics of the main travelmode are removed, allowing behavioral predictions whena new mode becomes available and affordable.TRIP FREQUENCY - By extending the idea of a daily timebudget, it is possible to get an aggregate model of tripfrequency as a function of time. Three sources of datawere merged to get a distribution of American trip milesas a function of distance in 1995 [3,4,5]. Figure 2 showsthis distribution by mode and Figure 3 shows thecumulative distribution by mode. What is striking is howcompletely dominant automobile travel is over all othermodes, even out to the 1000-2000 mile trips.