According to ICAO Doc 9931, a Continuous Descent Operation is an operation, enabled by airspace design, procedure design and ATC facilitation, in which an arriving aircraft descends continuously, to the greatest extent possible, by employing minimum engine thrust, ideally in a low drag configuration, prior to the final approach fix.
One of the main drawbacks of CDOs is their negative impact in airport/airspace capacity if current separation procedures are used. Thus, at present CDOs are usually flown during hours of low traffic demand in order to minimize ATC instructions leading to trajectory deviations and consequently to non-optimal operations. The Multi Parameter Guidance with Time and Energy Managed Operations (MPG-TEMO) is a novel Flight Management System (FMS) function developed in the framework of CleanSky that proposes to introduce strict time constraints in the CDO trajectory in order to give the ATC a powerful tool to cope with separation issues.
As stated in the call for tenders, the aim of this activity was to help define, prepare, perform and analyse two flight simulator experiments, which were a prerequisite to the Flight-Test. Furthermore, the partner was supposed to support the a7c integration process prior to the Flight Test and with the final test result analyis.
One of the key aspects of the proposed solution was to focus first efforts of the project in identifying the main changes that bring MTG TEMO to the CDO standard procedure, in order to early draft the main operational, safety and certification issues that must be taken into account during the project. To do so, the leader of this consortium had sought the participation of the UPC Department that had been involved in the previous MTG TEMO projects for the CSJU.
Extensive background of proposed engineers, researchers, as well as, Pilot Manager and flight crew ensured early identification of problems and valuable solutions proposition while fulfilling CSJU project objectives.
CONCORDE (Flight Operations for Novel Continuous Descent) is a Research & Development project funded by the Clean Sky Joint Technology Initiative and project-managed by Pildo Labs. It is designed to evaluate the viability of the Time and Energy Managed Operations (TEMO) concept.
TEMO is a green concept that enables aircraft to fly optimum speed trajectories whilst adhering to time constraints for spacing. For this purpose, TEMO algorithm has been developed using non-linear programming (NLP) solver for the trajectory prediction and optimisation. Once the optimum trajectory is computed, TEMO use of the aircraft autopilot to guide the aircraft using Speed-on-Elevator (SOE) control and with thrust set to idle. In case that TEMO cannot plan an energy neutral trajectory, the concept makes use of the autothrottle and auto speedbrakes systems to add or remove energy from the system at certain points of procedure.
Throughout the CONCORDE project framework, TEMO concept has been successfully evaluated by defining, executing and analysing different simulator and real experimental flight campaigns in order to demonstrate its operational feasibility and environmental benefits.
Initially, the Experiment Plan was drafted detailing the approach for testing the TEMO concept in two different simulators. The main points defined per each experiment were: analysis of TEMO software version to be used, research questions and hypotheses to be taken into consideration when analysing the experiment results, validation objectives and acceptance criteria to assess the experiment and simulator experiment scenarios.
According to the experiment plan, both TEMO simulation experiment were executed and analysed. First flight simulator experiment was performed at topic manager Amsterdam premises along 3 days (July 8th, 9th and 10th 2014) with the aim of demonstrating that TEMO concept reaches a Technical Readiness Level (TRL) 5, in which technology is validated in a relevant (simulated) environment. Second simulator experiment was performed at topic manager Braunschweig premises along 3 days (September 22nd, 23rd and 24th of 2014) with the aim of investigating the possibility of using TEMO on a modern aircraft with unmodified or only slightly modified avionic systems.
Afterwards, and based on the good results obtained in the simulator experiments, in October 2015 topic manager executed a flight trial campaign using a Cessna Citation II research aircraft at Eelde airport in the Netherlands. The trials, executed along 6 days, consisted of several descents and approaches demonstrating the TEMO feasibility and environmental benefits. CONCORDE consortium supported these experiments by providing technical assistance and contributing to the assessment tasks. Different TEMO conceptual variants were flown and it was demonstrated that the TEMO concept is feasible and enables arrival with timing errors below 10 seconds.
Finally, the different aspects involving TEMO concept integration into a commercial aircraft were analysed by identifying which should be the new elements on-board, TEMO-avionics interfaces and certification difficulties that could be faced in the process.