Most technology development for NOx reduction has focused on emissions at low altitude. However, the need for a technological breakthrough to significantly reduce cruise emissions is also evident. There is evidence that the effect of aircraft NOx emissions at cruise could be up to four times more important than that of aircraft CO₂. If this relationship is confirmed, cruise NOx will probably become a more urgent issue than low altitude NOx. The Twin-Annular Premixing Swirler (TAPS) combustor, a 4^th generation low-emissions technology, offers significant NOx reduction over state-of-the-art Low Emissions Combustor (LEC) technology for both low- and...