Ronald Verhoeven

Time and Energy Management During Descent and Approach: Batch Simulation Study

A novel integrated planning and guidance concept has been developed that optimizes aircraft trajectories from top of descent to the runway threshold to achieve a continuous engine-idle descent. The new concept, named time and energy managed operations, aims at reducing noise, gaseous emissions, and fuel burn while maintaining airport landing capacity by means of time management. Time and energy managed operations uses an optimization algorithm to minimize thrust and speed brake use through energy management by exchanging kinetic and potential energy. Sustained deviations during descent are corrected using a strategic or tactical approach. Time and energy managed operations is evaluated in a batch simulation study for various disturbances to test its robustness to disturbances and time constraints. Moreover, two different methods of correcting deviations are compared. Results show that time and energy managed operations allows idle descents while adhering to time constraints and can cope with disturbances ...

Time and Energy Management During Approach: A Human-in-the-Loop Study

Time and energy managed operations is a new integrated planning and guidance concept that optimizes the vertical aircraft trajectory to achieve a continuous engine-idle descent while satisfying time constraints. To investigate acceptance of the concept and the influence of pilot involvement on performance, time and energy managed operations were evaluated in a real-time simulation involving nine airline pilots. Three human–machine interface variants were tested; these varied in the level of information presented. The results were compared to computer simulations with a zero-delay pilot response model, to evaluate the effect of pilot reaction time variation on performance and environmental impact. Results indicated that the effects of pilot response delays are limited. Pilots preferred the human–machine interface variant that included a timer to support accurate selection of flaps and gear. Although the timer did not significantly affect system performance, it did reduce variation in the pilot response. Re...

Enhancement of a time and energy management algorithm for continuous descent operations

In previous research, an aircraft trajectory planning algorithm was developed aiming at optimizing continuous descent operations with required times of arrival at given waypoints. A non-linear optimal control problem was solved by using direct transcription methods. In this paper, enhanced models for the same optimization framework are presented, im- proving the accuracy of the optimized trajectories. These new models take into account wind, realistic atmospheric conditions, curved trajectories and general improvements in the aircraft dynamics model. Preliminary results are shown in a hypothetical scenario where trajectories are optimized from cruise altitude to the runway with different required times of arrival at the threshold. The effects of wind and non-standard atmospheres can be easily appreciated.

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 NOX emissions. Furthermore, the allowed deviations between planned and actual combined with human response could result in too early arrivals.

Performance comparison of guidance strategies to accomplish RTAs during a CDO

Continuous Descent Operations with Controlled Times of Arrival (CTA) at one or several metering fixes could enable environmentally friendly procedures without compromising capacity. This type of flight operation requires advanced on-board systems not only able to compute a plan satisfying Required Times of Arrival (RTAs), but also to safely and efficiently guide the aircraft during the execution of the descent such that RTAs are accurately accomplished. The primary aim of this paper is to compare the performance (in terms of environmental impact mitigation and ability to fulfill operational constraints) of four guidance strategies: tactical, strategic, hybrid and Model Predictive Control (MPC). A high fidelity flight simulator has been configured, and several descents to Barcelona-El Prat airport (Spain) have been simulated in presence of weather forecast and aircraft performance modeling errors. Results show that MPC is the most robust in terms of energy and time deviation, providing at the same time excellent environmental impact mitigation.

Performance comparison between TEMO and a typical FMS in presence of CTA and wind uncertainties

Continuous Descent Operations (CDO) with Controlled Times of Arrival (CTA) at one or several metering fixes could enable environmentally friendly procedures without compromising airspace capacity. Extending the current capabilities of state-of-the-art Flight Management Systems (FMS), the Time and Energy Managed Operations (TEMO) concept is able to generate optimal descent trajectories with an improved planning and guidance strategy to meet CTA. The primary aim of this paper is to compare the performances of TEMO (in terms of fuel consumption and time error) with respect to a typical FMS, that is an FMS without re-planning mechanism during descent based on time or altitude errors. The comparison is performed through simulation, using an A320-alike model and considering several scenarios in presence of CTA and wind uncertainties. Results show that TEMO is capable of guiding the aircraft along the optimal trajectory still complying with a CTA, even in presence of wind prediction errors. For a same scenario, a typical FMS without re-planning capabilities or tactical time-error nulling mechanism would miss the CTA in most cases.

Use of touch screen display applications for aircraft flight control

Touch screen technology is rapidly and progressively entering the world of commercial avionics and being introduced inside the cockpit. This paper presents the main results of a piloted experiment conducted by the Netherlands Aerospace Centre (NLR) as part of the ACROSS (Advanced Cockpit for Reduction Of StreSs and workload) project of the EUs 7th Frame Work Programme, see www.across-fp7.eu. The experiment focused on the use of novel touch screen applications in the cockpit of civil transport aircraft and investigated the potential for (peak-) workload reduction. Three different touch screen applications and associated experimental results will be discussed. Firstly the so-called tactical flight control operations of an aircraft is addressed, like changing the aircrafts speed, heading, altitude, flight level or vertical speed. Secondly a novel late runway change functionality was set up for supporting the crew decision to accept a new landing runway late in the approach while still allowing safely and easily configuring the aircraft cockpit systems. Similarly the third new application allowed for a fast and easy alternate airport selection process and subsequently a new route creation and selection towards the alternate airport. A piloted experiment was held in which ten airline crews participated on NLRs full motion flight simulator (GRACE). Baseline formed todays aircraft operations without touch screen functionality. Subjective workload and situation awareness ratings were used, as well as objective eye-tracking measurements and time-analysis. Also the effect of turbulence (intensity) was investigated. Main results for the tactical flight control application showed further room for design improvements in the field of workload reduction, especially under more severe turbulence. For the other two cockpit touchscreen applications the results supported the conclusions that pilot workload decreased, situation awareness improved and task execution was much faster and easier compared to the baseline.

Optimization of the vertical trajectory through Time and Energy management: A Human-in-the-Loop Study

A new on board integrated planning and guidance concept has been developed that attempts to optimize the vertical trajectory to achieve a continuous engine-idle descent while satisfying time constraints. The new concept, named Time and Energy Managed Operations (TEMO), reduces noise, gaseous emissions and fuel consumption, while adhering to time constraints yielding control points for aircraft spacing and sequencing. The concept allows small deviations between planned and actual trajectory within pre-set boundaries and calculates a new trajectory when these deviations are exceeded. The concept was evaluated in a Full Motion Flight Simulator at the premises of the National Aerospace Laboratory (NLR) in Amsterdam. Six pilots were invited to provide feedback of the TEMO concept with respect to operation, safety and certification requirements and to demonstrate that the TEMO Technology Readiness Level (TRL) achieved level 5, in that the technology is demonstrated in a relevant (simulated) environment. Conclusions drawn from the responses to the questionnaires and any issues that have emerged indicate that TEMO is a promising concept that may play a valuable role in ATM facilitation. Recommendations for future research include the use of more involved scenarios and active participation of ATC.

Time and energy managed operations

Human response has little effect on environmental impact. While performance was slightly improved, TEMO does not require a fully automated cockpit.