Time and energy management during descent: Human vs automated response

A new integrated planning and guidance concept is developed which optimizes the vertical trajectory to achieve a continuous engine-idle descent while satisfying ATC time constraints, named Time and Energy Managed Operations (TEMO), TEMO aims at reducing noise, gaseous emissions and fuel consumption by optimizing a 4D trajectory. Using time constraints at the IAF and the runway threshold yields two control points for flow management and arrival spacing. The optimization routine onboard the aircraft calculates an energy-neutral profile (meaning, no use of engine thrust and/or speedbrakes) which complies with given constraints. When no trajectory is found using idle-thrust, energy is added or removed to the aircraft by using minimal amounts of thrust and/or speedbrakes to obtain an energy-optimal profile. Deviations from this profile are allowed within pre-set boundaries; when these boundaries are exceeded, a new trajectory is calculated. The concept was evaluated in a human-in-the-loop simulation study and compared with simulations performed using a zero-delay pilot response model. This comparison allows an identification of deviations due to variations in human response. The comparison shows that the effect of human response is limited since the automated response showed only minor improvements in time performance, noise levels and NO_X emissions. Furthermore, the allowed deviations between planned and actual combined with human response could result in too early arrivals.