Emergency Landing Research Articles

Nonlinear dynamic modeling and body injuries analysis of human/seat system under vertical impact

Predicting the responses and injuries of seated pilots caused by emergency landing or ejection is significant for the design of ejection seats. A nonlinear two-dimensional multi-body human/seat model is proposed to predict the responses and body injuries exposed to vertical impact. Then a new force identification method is presented and applied to obtain the external excitation of the system. In addition, the parameters of this model are optimized based on the Error Assessment of Response Time Histories (EARTH) metric and Non-dominated Sorting Genetic Algorithm II (NSGA-II). Furthermore, utilizing the proposed model, this research predicts body injuries with different impact intensities. With body injuries as output, the influence of input parameters is assessed by global sensitivity analysis (GSA) methods. The result shows that the backrest angle plays a crucial role in body injuries. Finally, the influence of backrest angle is further analyzed to obtain the variation of body injuries with backrest angle. This research provides guiding principles for the subsequent design of ejection seats.

Latest Advances in the Global Navigation Satellite System—Reflectometry (GNSS-R) Field

The global navigation satellite system-reflectometry (GNSS-R) field has experienced an exponential growth as it is becoming relevant to many applications and has captivated the attention of an elevated number of research scholars, research centers and companies around the world. Primarily based on the contents of two Special Issues dedicated to the applications of GNSS-R to Earth observation, this review article provides an overview of the latest advances in the GNSS-R field. Studies are reviewed from four perspectives: (1) technology advancements, (2) ocean applications, (3) the emergent land applications, and (4) new science investigations. The technology involved in the GNSS-R design has evolved from its initial GPS L1 LHCP topology to include the use of other GNSS bands (L2, L5, Galileo, etc.), as well as consider RHCP/LHCP-receiving polarizations in order to perform polarimetric studies. Ocean applications have included developments towards ocean wind speed retrievals, swell and altimetry. Land applications have evolved considerably in the past few years; studies have used GNSS-R for soil moisture, vegetation opacity, and wetland detection and monitoring. They have also determined flood inundation, snow height, and sea ice concentration and extent. Additionally, other applications have emerged in recent years as we have gained more understanding of the capabilities of GNSS-R.

Pennsylvanian glacial cycles in western Gondwana: an overview

Abstract The Pennsylvanian on the western rim of Gondwana can be considered a time of significant contrasts in terms of environments, revealing a unique translatitudinal disposition of the South American continent, where glaciomarine deposits and peat-forming environments, situated further south, coexisted with marine carbonate platforms and aeolian dune fields, in terrains further north. This peculiar record creates an opportunity to better understand the teleconnections of glaciation and deglaciation during the Late Paleozoic Ice Age (LPIA) between mid and low latitude regions. In the last decade, radiometric dating together with marine microfossils (mostly conodonts) has enabled a better understanding of the timing and duration of deposition of different sedimentary environments found in the climate belts that originated from a global ice-house regime. These advances in the chronostratigraphical positioning of sedimentary deposits also allow a more precise correlation between them, making it possible to estimate cause–effect patterns arising from the growth and decay of glaciers in this portion of Gondwana. This contribution aims to present an overview of the main climatic–environmental events that took place during the Pennsylvanian and to associate them with the floristic changes that occurred in the emergent lands based on palaeobotanic and palynological information. The record from the west rim of Gondwana could be roughly divided into Early, Middle and Late Pennsylvanian, exactly as proposed in the geological time-scale.

Effectiveness of Automatic Safety Systems in Reducing General Aviation Fatalities

General aviation accounts for 95% of fatal aviation accidents in the United States. Many of these fatalities may be preventable with the inclusion of advanced advisory or automatic aircraft safety systems; however, past research has rarely focused on the effect such systems could have if applied to general aviation. This paper addresses this gap by starting with proposed safety systems and scoring their effectiveness using detailed accident data rather than the more common approaches of analyzing accident categories or polling subject matter experts. Using a data-driven logical model, this paper evaluates four systems (terrain impact prevention, upset prevention, turbulence avoidance, and emergency landing) for potential to reduce fatalities. The scoring process appears in some detail, which starts with system requirements and National Transportation Safety Board data as inputs and results in expected fatal accident reductions. The analysis estimates that implementing all four systems may result in a 66.5% reduction in general aviation fatalities, with terrain impact prevention alone resulting in a possible 30.7% reduction. These results motivate immediate effort toward implementation and certification of aircraft safety systems into general aviation, not only to save the lives of hundreds of pilots and passengers a year, but also to prime small aircraft transportation for future developments.

Operation “Ryanair”

Aim. To reveal the essence, content, goals, objectives and methods of the special operation of the American special services related to the emergency landing of a Ryanair aircraft at the airport in Minsk, as a result of which the KGB of the Republic of Belarus detained oppositionists R. Protasevich and S. Sapega.Methodology. The study was carried out using the methods of analysis, synthesis, generalization and interpretation of the results.Results. It has been established that, in terms of its scheme and manner of execution, the “Ryanair case” is identical to the operation “Doping Scandal with WADA” carried out by the US intelligence agencies against the Russian Federation in 2015–2018. The goal of the Ryanair operation is the same as in the WADA scandal: make those who were repeatedly caught in a lie admit the allegations on all counts; the form of the operation is an operational experiment (provocation). Thus, the Ryanair operation is a combination of techniques, methods and tricks previously worked out by US intelligence in a whole series of operations against the Russian Federation.Research implications. Information about the latest forms and methods of organizing and conducting information operations, such as Operation Ryanair (carried out by the US intelligence agencies against Belarus), can be used in the work of state bodies responsible for organizing a systemic counteraction to informational aggression by foreign states, and will also be of use to political scientists, political technologists and specialists in counteracting destructive political technologies.

Airplane Emergency Landing Due to Quick Development of Mesoscale Convective Complexes

Some meteorological phenomena in South America develop quickly and take on large dimensions. These phenomena cause disasters for aviation, such as incidents and accidents. Mesoscale convective complexes (MCCs) forced a commercial airplane into an emergency landing at Ezeiza International Airport in Buenos Aires (Argentina) in October 2018. The airplane took off from São Paulo (Brazil) to Santiago (Chile) and had to alternate to Ezeiza after encountering unanticipated agglomerations of MCCs along the flight route; its structure was seriously damaged, which affected the safety of the flight. A synoptic and thermodynamic analysis of the atmosphere, prior to the event, was made based on GOES16 infrared satellite data, radiosonde data, maps of several variables such as stream lines, temperature advection, surface synoptic maps and layer thickness from CPTEC/INPE and NCEP reanalysis data. The main observed processes that influenced the formation and development of conglomerates of MCCs were the following: (1) the cyclogenesis of a baroclinic cyclone on the cold front; (2) the coupling of subtropical and polar jet streams; (3) the advection of warm and humid air along a low-level jet stream. Recommendations for meteorologists in weather forecasting and for aviators in flight safety were prepared.

The MPU RX-4 Project: Design, Electronics, and Software Development of a Geofence Protection System for a Fixed-Wing VTOL UAV

Unmanned aerial vehicles (UAVs) are at the forefront of this century’s technological shift, becoming ubiquitous in research and market areas. However, as a UAV navigates autonomously, there are unanticipated occasions, e.g., collisions with dynamic obstacles or loss of data provided by the global navigation satellite system (GNSS), where the aircraft has to change its mission plans. In particular, to be protected from possible accidents, the platform’s geofence protection system should adjust the trajectory appropriately when obstacles are detected and select the proper ground surface when emergency landing is prompted. As these processes require fast reaction times, utilizing low latency sensors and algorithms is necessary. This article proposes a complete and low-complexity geofence protection system for recognizing moving objects and assessing the ground surface’s suitability using onboard sensing and processing modules. The proposed system is implemented on a novel fixed-wing UAV, designated as MPU RX-4, which features an unconventional flying wing layout and vertical take-off and landing (VTOL) capabilities. Our system is based on a forward-facing laser imaging, detection, and ranging (LIDAR) sensor and three downward-facing laser rangefinders. We take advantage of the high-precision distance measurements and operational speed to identify moving obstacles using the LIDAR module, while the ground’s slope and the existence of any obstacle therein are computed through the rangefinders. First, the article describes the UAV design procedure and its aerodynamic performance characteristics, which allowed us to evaluate our approach on a testbed aircraft. Then, the evaluation protocol shows that our system can perform robustly and under real-time constraints reaching an overall latency of only 165.5 ms, sufficient for reliable detection and avoidance of moving obstacles.

Segmentation and Evaluation of Crack Image From Aircraft Fuel Tank via Atrous Spatial Pyramid Fusion and Hybrid Attention Network

Jet fuel leaks not only waste resources and increase costs but also pose a risk of emergency landings and aviation accidents. With the blossom and implementation of deep learning, crack segmentation techniques have been rapidly developed in many fields. However, it is struggle to get accurate and complete crack segmentation results because of images’ complex background environment. To address this issue, we collected and labeled a dataset of 2824 crack images from the surface of aircraft fuel tank, named CAFT2800. And this article presents an atrous spatial pyramid fusion and hybrid attention network based on deep learning to deal with the complicated environment. The backbone of network uses a hierarchical structure Swin Transformer to extract features. In the neck of the network, an atrous spatial pyramid fusion module is proposed to further capture contextual information in multiple scale. Unlike the ASPP module, which aggregates image-level information with pooling, we abandon this operation according to the characteristics of crack. And the neck structure is designed for fusing high-level semantic information to all scales. At the gate between the neck and the decoder head, a SK (selective kernel) block is embedded into the network to recalibrates channel-wise feature responses. Due to the morphological characteristics of crack, we propose an evaluation index, Thinning F1 score (TFscore), which is more meaningful compared to the commonly used F1 score. Sufficient control experiments were conducted on the CAFT2800 dataset and two complicated environment benchmarks (DeepCrack and GAPs) to test the effectiveness of the network, and our method achieved superior performance. Source code and the CAFT2800 are available at https://github.com/Gu-EH/CAFT2800.

Hitna medicinska stanja tokom komercijalnih letova avionom - "Ima li lekara u avionu?"

Almost four billion passengers travel aboard commercial airliners every year. Last year In-flight medical emergencies (IMEs) were relatively common and occurred in a complex environment with limited medical resources. More recent data shows that IMEs occur in one passenger for every 604 flights or 24-130 IMEs for every one million passengers, more often in people over 70 years old. Due to the drop in barometric pressure, there are specific conditions in the aircraft passenger cabin that can affect the occurrence of IMEs. Most importantly it is hypobaric hypoxia, which can lead to the development of hypoxia-related symptoms in chronic patients with respiratory, cardiovascular, and hematological diseases. With reduced barometric pressure gases in body cavities and medical equipment can expand by 30%, this can lead to IMEs in recently operated patients (wound dehiscence, bleeding), middle ear and sinus diseases, subocclusions, and lung problems (pulmonary bulla). Other factors that contribute to the occurrence of IMEs are limited movement (deep vein thrombosis), dry and cold air (dehydration), jet lag, turbulence, and psychological stress. IMEs most commonly involve syncope or near-syncope (32.7%), gastrointestinal (14.8%), respiratory (10.1%), and cardiovascular (7.0%) symptoms. Because of ethical, and in some countries also legal responsibilities, doctor-passengers are a great help in the treatment of IMEs. Emergency landing of the aircraft when an IME occurs happens in an estimated 4.4% of cases. Knowing the influence of the specific ambient conditions in the plane on physiological processes in the body is of great importance for determining the absolute and relative contraindications for flying by plane. Doctor-passengers have an important role in the treatment of IMEs. This work aims to introduce us to the specific ambient conditions in the aircraft cabin and their influence on the physiology of the human body, the most common IMEs that occur under the influence of those conditions, the role of the doctorpassenger as well as the absolute and relative contraindications for flying by plane.

South African Airways makes an emergency landing into business rescue: Some burning issues

South African Airways makes an emergency landing into business rescue: Some burning issues

Risk Evaluation of Single-engine Turboprop Commercial Operations in IMC

The main topic is aimed at risk assessment and possible risk mitigation of single-engine turboprop (SET) aeroplanes as part of commercial air transport (CAT) and operated in instrument meteorological conditions (IMC) or at night. The paper in the introductory part describes the theoretical issues of the SET-IMC flights and reveals the reasons why the approval of this type of operation was needed. The used analysis verifies later compared results of risk segments along the two compared flight paths, depending on various determinants affecting aircraft performance. The outputs alternatively present new possibilities for enhancing safety in case of engine flameout and following emergency landing procedures. The aim of the paper is also to provide an overview of legislation and regulations related to the CAT operations with SET aeroplanes, which also reflects risk evaluation, especially in IMC.

Structural Analysis of a Composite Passenger Seat for the Case of an Aircraft Emergency Landing

Aviation authorities require, from aircraft seat manufacturers, specific performance metrics that maximize the occupants’ chances of survival in the case of an emergency landing and allow for the safe evacuation of the aircraft cabin. Therefore, aircraft seats must comply with specific requirements with respect to their structural integrity and potential occupant injuries, which are certified through the conduction of costly, full-scale tests. To reduce certification costs, computer-aided methods such as finite element analysis can simulate and predict the responses of different seat configuration concepts and potentially save time and development costs. This work presents one of the major steps of an aircraft seat development, which is the design and study of preliminary design concepts, whose structural and biomechanical response will determine whether the concept seat model is approved for the next steps of development. More specifically, a three-occupant aircraft seat configuration is studied for crash landing load cases and is subjected to modification iterations from a baseline design to a composite one for its structural performance, its weight reduction and the reduction of forces transmitted to the passengers.

Guidance and control for autonomous emergency landing of the rotorcraft using the incremental backstepping controller in 3-dimensional terrain environments

This paper treats the approach to safe emergency landing for an autonomous rotorcraft in 3-dimensional terrain environments. The autorotation flight that the rotorcraft flies without the power supply is dangerous and needs the high-skilled control ability of the pilot. Ordinary, this flight is divided into three phases: Entry, Steady-Descent, and Flare phase. The emergency landing trajectory is generated by imitating each phase. The Trajectory optimization method using the high-fidelity math model is applied to the entry and flare phase to consider the complex dynamics of the rotorcraft. To generate a steady-descent phase trajectory without obstacle collisions, one of the path planning methods, the improved Rapidly-exploring Random Tree algorithm is used. The Incremental Backstepping controller is adopted as the trajectory tracking controller. Simulation is conducted in the One Engine Inoperative condition. Through the simulation, it is shown that the method proposed in this paper guarantees the safe landing of the rotorcraft in an emergency like engine failure.

Safety Flight Control for a Quadrotor UAV Using Differential Flatness and Dual-Loop Observers

Focusing on a quadrotor unmanned aerial vehicle (UAV), the presence of unintended actuator faults and external disturbances increases the risk of a crash. Although plenty of efforts have been devoted, how to integrate capability analysis into safety control design is still an open issue. This article presents the design of a safety control system for quadrotor UAVs. Firstly, a system capability analysis method based on a differential flatness algorithm is developed, so that the derivatives (i.e., velocity, jerk, and snap) of flight trajectory can be formulated as flat variables. A tradeoff between system capability and permissible flight maneuverability is made to avoid actuator saturation. Secondly, dual-loop nonlinear disturbance observers are exploited to identify the actuator faults and disturbances, which can thereby be handled by a cascade control scheme. Moreover, the trajectory is regenerated online at the expense of degraded flight maneuverability or even emergency landing, in view of the remaining actuator control authority. When comparing to the existing methods, the gap among safety control, trajectory generation, and system capability analysis is bridged to ameliorate practical flight safety. Finally, flight tests are carried out to demonstrate the unique merits of the proposed system.

SEARCH FOR SMALL-SIZED OBJECTS ON THE UNDERLYING SURFACE IN FRONT OF THE AIRCRAFT

The method of searching of small-sized ground or surface objects with unknown coordinates is proposed. The search is carried out using the thermal imaging or other IR remote sensing system (RS) of underlying surface (US) in front of the aircraft. The small size of objects requires the use of narrow fields of view for detection and recognition at ranges that allow to carry out operational actions, which are provided for by the flight mission for rescue operations on land and at sea or for aircraft emergency landing on an unprepared site. Two tasks are solved: 1) the maximization of the guaranteed bandwidth of objects searching on US with given characteristics of RS and aircraft speed; 2) the determination of the optimal characteristics of remote sensing systems and aircraft speed for a given search bandwidth of the US.A periodic change in the azimuthal orientation of the narrow field of view (automatic scanning of the US by the field of view of the IR system) is used for solving given tasks. For a given operating range of the IR system the proposed algorithm ensures that the pilot or operator can view the runway on US without “dead” zones (unseen areas). The optimal value of the search effort corresponding to the detection and recognition of objects is determined. The proposed algorithm implements symmetrical scanning (scanned areas of the same shape are formed to the left and right of the flight path on US). The symmetric scanning equation is derived for prediction search efficiency. The solution of given equation makes it possible to find the dependence of the guaranteed search bandwidth on the operating range of ranges in which detection and recognition are possible for given weather conditions. The examples of using the derived equation when searching for objects in simple and difficult weather conditions are given.

Monocular-Vision-Based Precise Runway Detection Applied to State Estimation for Carrier-Based UAV Landing.

Improving the level of autonomy during the landing phase helps promote the full-envelope autonomous flight capability of unmanned aerial vehicles (UAVs). Aiming at the identification of potential landing sites, an end-to-end state estimation method for the autonomous landing of carrier-based UAVs based on monocular vision is proposed in this paper, which allows them to discover landing sites in flight by using equipped optical sensors and avoid a crash or damage during normal and emergency landings. This scheme aims to solve two problems: the requirement of accuracy for runway detection and the requirement of precision for UAV state estimation. First, we design a robust runway detection framework on the basis of YOLOv5 (you only look once, ver. 5) with four modules: a data augmentation layer, a feature extraction layer, a feature aggregation layer and a target prediction layer. Then, the corner prediction method based on geometric features is introduced into the prediction model of the detection framework, which enables the landing field prediction to more precisely fit the runway appearance. In simulation experiments, we developed datasets applied to carrier-based UAV landing simulations based on monocular vision. In addition, our method was implemented with help of the PyTorch deep learning tool, which supports the dynamic and efficient construction of a detection network. Results showed that the proposed method achieved a higher precision and better performance on state estimation during carrier-based UAV landings.

Mangrove rehabilitation planning with ecological and geospatial approaches in Cemara Village, Indramayu, West Java

Several rehabilitation activities have been carried out by the government in Indramayu Regency, but have not been able to restore the condition of the mangrove. Hence, it is necessary to rehabilitate potential land. The aim of this study is to formulate the direction of rehabilitation planning in Cemara Village, Indramayu based on an ecological approach and mangrove ecosystem. The method used in this study is geospatial approach that is integrated with field quantitative data. The result shows that the total area that is potential to be rehabilitated in Cemara Village is 1,012.020 ha, which consists of 285.390 ha (28.2%) vegetated area and 726.630 ha (71.8%) non-vegetated area. Furthermore, the plan of rehabilitation in Cemara village is based on the consideration of mangrove typology, mangrove stand density, physical parameters, and land use. Recommendation for rehabilitating mangrove forest on land with low mangrove density and emergent land by performing intensive planting, on pond land by performing sylvofishery planting, on land with moderate mangrove density by enrichment planting, and on land with high mangrove density by carrying out maintenance for protective function.

A formal toolchain for offline and run-time verification of robotic systems

Validation and Verification (V&V) of autonomous robotic system software is becoming a critical issue. Among the V&V techniques at our disposal, formal approaches are among the most rigorous and trustworthy ones. Yet, the level of skills and knowledge required to use and deploy formal methods is usually quite high and rare. In this paper, we describe an approach that starts from a regular, but rigorous, framework to specify and deploy robotic software components, which can also automatically synthesize a formal model of these components.We describe how we can execute the resulting formal model, in place of a traditional implementation, and show how this provides the opportunity to add powerful monitoring and runtime verification capabilities to a system, e.g., to prevent collisions, or trigger an emergency landing. Since the runtime used to execute formal models is specifically designed to be faithful to their semantics, every execution (in the implementation) can be mapped to a trace in the specification. As a result, we can also prove many interesting properties offline, using model-checking techniques. We give several examples, such as properties about schedulability, worst-case traversal time, or mutual exclusion.We believe that having a consistent workflow, from an initial specification of our system, down to a formal, executable specification is a major advance in robotics and opens the way for verification of functional components of autonomous robots and beyond. We illustrate this claim by describing a complete example based on a genuine drone flight controller.

Tension-bending risk curves for the ATD lower lumbar spine subjected to oblique impact under FAA emergency landing conditions

With the increasing use of obliquely oriented airline seating configurations, the objective of the present study was to develop injury risk curves for the lower lumbar spine load cell of the FAA-H3 dummy. A new spinal criterion, termed FAA-LLtb, which is a linear combination of tensile load with forward flexion, and lateral bending moments, was developed to predict the injuries occurring to the lower lumbar spine and sacrum regions. The injury definition required for the metric was obtained from the matched PMHS tests. The loading conditions included variations in peak sled accelerations, the presence or absence of an armrest, the belt type (single and dual lap-belt systems), and seat orientation relative to impact vector (45° and 30°). The developed ATD risk curve based on the combined metric represents AIS = 3+ injury probability for the lower lumbar spinal levels. The survival analysis estimated normalized confidence interval size (NCIS) values were in fair and good categories at all levels of probability. At 5%, 25% and 50% risk levels, the combined loading metric values were 1.6, 1.8, and 2.0, respectively. The study estimated that the combination of bending moments and tensile load was a better injury criterion than any individual metric for assessing the injury to the lower lumbar spine and pelvis regions under oblique loading.

Research on Optimization Design of Key Energy-Absorbing Structure of a Helicopter Seat Based on Human–Seat Coupling System

During the process of emergency landing, the energy of the impact in the vertical direction is dissipated through the deformation of the structure. The landing load is transferred to the spine of the occupant through the landing gear, the fuselage and finally the seat. This can cause serious damage to the human body. Since the seat is in direct contact with the human body, the energy absorption capacity of the seat is the most direct manifestation of the Crashworthiness of the helicopter. The solutions proposed in the paper may reduce the impact of the seat on the spine of the occupant during the collision by optimizing the key energy-absorbing structure. Taking the seat of the H135 helicopter as a case, the mechanical model of the human–seat coupling system, which is based on the theories of energy methods and structural mechanics, is simplified. Additionally, the simulation was considered reasonable by comparing the simulation results with the results of crashworthiness tests. On the basis of the above, the optimization of the key energy-absorbing structure of the seat was completed by using Latin hypercube sampling and the kriging model. Overall, the optimization effectively enhanced the crashworthiness of this helicopter seat and provided a solution for the passive safety design of aviation seats.