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Flight decks and free flight: Where are the system boundaries?
Published in Don Harris, Wen-Chin Li, Decision Making in Aviation, 2017
A different solution proposed for this problem is free flight, defined as “a safe and efficient flight operating capability under instrument flight rules in which the operators have the freedom to select their path and speed in real time” (RTCA, 1995). The meaning of free flight is that pilots are no longer restricted to fly inside the established air corridors. Instead pilots and airlines are allowed self-optimisation of the routes by being given control over route selection and changes in speed, flight path, and altitude—all subject to Instrument Flight Rule conditions. According to its promoters, free flight is expected to lead to significant advantages in terms of time and fuel savings for operators and airlines (Liang and Chin, 1998). It will allow pilots on their own initiative to avoid weather and other factors that crop up during flight. Free flight, however, does not mean that pilots can fly where and when they please. Air traffic restrictions will still be imposed to ensure safe separation of aircraft.
The Air Transport Future
Published in Harry W. Orlady, Linda M. Orlady, John K. Lauber, Human Factors in Multi-Crew Flight Operations, 2017
Harry W. Orlady, Linda M. Orlady, John K. Lauber
The Free Flight goal is to provide greater efficiency in flight operations by increasing airport arrival and departure rates, reducing enroute separations, and performing traffic flow management more efficiently. It is a highly worthwhile goal. Free Flight will attempt to take full advantage of the potential of GPS/ADS. GPS is a key element of CNS/ATM, the FAA’s proposed Air Traffic Management System. In all probability the NAS’ current operational concept will be replaced. Free Flight does limit pilot flexibility in certain situations, such as those when separation in congested airspace or at busy airports is required.
Automated UAV path-planning for high-quality photogrammetric 3D bridge reconstruction
Published in Structure and Infrastructure Engineering, 2022
Feng Wang, Yang Zou, Enrique del Rey Castillo, Youliang Ding, Zhao Xu, Hanwei Zhao, James B.P. Lim
To narrow this gap, this paper presents a novel 3D path planning method for generating a high-quality bridge model with improved geometric precision and model quality. The goal of the path planning is to identify a set of effective camera viewpoints (CVs) and flight trajectories to guarantee: 1) full coverage of the bridge components of interest, 2) enough overlap between any consecutive images, 3) GSD constraints derived from inspection requirements, and 4) UAV flight safety and obstacle avoidance. This method firstly utilises a simple BIM model of the target bridge to identify reasonable CVs for capturing various surfaces and edges of the bridge to ensure the full coverage of the whole bridge with overlap and GSD constraints. Secondly, those CVs that are in space occupied by bridge components or do not meet flight safety rules are replaced with alternative viewpoints. Finally, a feasible obstacle-free flight trajectory through all valid viewpoints is generated. This paper also presents two prototypes developed to automate flight path planning and on-site UAV image acquisition, respectively. A typical girder bridge in New Zealand is selected to evaluate the proposed method. The scope of this study is also limited to those inspection areas that have good UAV GPS signals. The rest of this paper is organised as follows. Section 2 describes the workflow and details of the proposed method. In Section 3, a field experiment to validate the proposed method is illustrated. Section 4 illustrates the performance and the limitation of the proposed method. Conclusions are given in Section 5.
A Nuclear Decay Micropropulsion Technology Based on Spontaneous Alpha Decay
Published in Nuclear Science and Engineering, 2021
Shiyi He, Yan Xia, Fei Xu, Leidang Zhou, Xiaoping Ouyang
Nowadays, studies on spacecraft that require high stability and high precision have been a heat spot. Thus, micropropulsion technology becomes one of the key technologies in drag-free flight.9 Drag-free flight technology is used to offset the resistant force and to guarantee that the spacecraft moves only following gravitation. This technology has been used in earth gravitational measurement, gravitation theory verification, and high-accuracy earth observation. Its realization has mostly relied on the various micropropulsion systems. Thrust demands are commonly less than 1 μN. For the Laser Interferometer Space Antenna (LISA) project,10 the thrust to achieve drag-free flight and track accuracy demand is as low as 4.6 × 10−4 nN. Traditional propulsion technologies,11 including cold gas and electrical propulsion systems, have been well applied to the micropropulsion field. The field emission electric propulsion system at ALTA S.p.A. in Italy12 was able to generate thrusts of 0.1 to 150 μN and specific impulses of 3000 to 4500 s, while the dry mass of the whole thruster system was 1.4 kg (0.11 mN/kg on average). Advanced propulsion systems such as solar sails13 and laser propulsion systems14 are maturing gradually as well. In the spacecraft IKAROS, launched by the Japan Aerospace Exploration Agency,15 the thrust of photon propulsion was tested. A 200-m2-square sail received the solar radiation pressure force of 1.12 mN at 1 AU distance from the sun, thus the areal thrust was 0.56 nN/cm2.
Cognitive work analysis in the conceptual design of first-of-a-kind systems – designing urban air traffic management
Published in Behaviour & Information Technology, 2018
Jonas Lundberg, Mattias Arvola, Carl Westin, Stefan Holmlid, Mathias Nordvall, Billy Josefsson
Further, fixed and shared use tube networks (the Zones concepts in the Metropolis project (Sunil et al. 2015)) could also be used. However, then traffic inside the tubes must also be managed. Either the tubes must be segmented (reserved for specific drones during specific times), or traffic inside the tubes must be monitored (as points) or be based on self-separation (unstructured traffic). However, the problem of self-separation inside tubes may be simpler than that of self-separation in free flight. This is because admittance to specific tubes may be based on drone performance and technology level. There could for instance, be a high-speed tube for drones with specific separation capabilities and high-speed performance. Different configurations may be based on planning of specific flights or based on regularly occurring patterns during different times of the day.