Emergency Flight Planning Applied to Total Loss of Thrust

Abstract

Autopilot systems are capable of reliably following flight plans under normal circumstances, but even the most advanced flight-management systems cannot provide robust response to most anomalous events including in-flight failures. This paper describes an emergency flight-management architecture that can be applied to piloted or autonomous aircraft, with focus on the design and implementation of an adaptive flight planner (AFP) that dynamically adjusts its model to compute feasible flight plans in response to events that degrade aircraft performance. A two-step landing-site selection/trajectory generation process defines safe emergency plans in real time for situations that require landing at an alternate airport. A constraint-based search algorithm selects and prioritizes feasible emergency landing sites, then the AFP synthesizes a segmented trajectory to the best site based on postfailure flight dynamics. The AFP architecture is general for any failure situation; however, operational success is guaranteed only with accurate postfailure performance characterization and a trajectory generation strategy that respects degraded flight envelope boundaries. A real-time segmented trajectory planning algorithm and case study results are presented for total loss of thrust failure scenarios. This emergency is surprisingly common and necessitates an immediate approach and landing without a go-around option.

Mathematical Models for Aircraft Trajectory Design: A Survey

“…Furthermore, the path length is used as the search criterion, which is less appropriate when compared to flight time for emergency landing, or fuel consumption for normal flight. Related work includes the investigation of Atkins et al [3], where the problem of emergency landing due to the loss-of-thrust was studied using a hybrid approach. A two-step landing-site selection/trajectory generation process was adopted to generate safe emergency plans in real time under situations that require landing at an alternate airport.…”

Methodology for Path Planning with Dynamic Data-Driven Flight Capability Estimation

“…A common damage scenario includes an engine-out emergency where one engine is failed or has reduced thrust and the planner must find a safe strategy to land. 13,14 Other works investigate the effects of softened panels or removal of entire airframe sections as in damage-tolerant control. 15 A strong focus is placed on stability and tracking of the developed control laws which derive from adaptive control schemes, model reference control, model predictive control, and neural networks.…”

Evaluating Risk to People and Property for Aircraft Emergency Landing Planning

“…Landing sites can be prioritized before flight planning [5,12] with subsequent focus on a single site, or sites can be prioritized with additional consideration of flight plan risks after the plan is computed [3,11,13]. Flight planning can be based on database, sensor, or combined information.…”

“…Runway choice is usually performed using traditional aviation databases providing information such as runway properties, airport facilities, and wind [12]. The risk associated with the planned flight to each landing site can also be incorporated into the landing site decision [13].…”