Ground Proximity Warning System Research Articles

An integrated hesitant 2-tuple linguistic Pythagorean fuzzy decision-making method for single-pilot operations mechanism evaluation

Single-pilot operations (SPO), i.e., one pilot on board the flight in charge of all the operations, has received extensive attention in recent years. SPO involves several participants including the pilot, the autopilot, and the ground operator, and it is of great significance to determine the roles of these participants under the SPO mechanism. However, the evaluation of SPO mechanism has received little attention. Aiming at providing a reliable approach for SPO mechanism evaluation under uncertainty, this paper proposes a novel hesitant 2-tuple linguistic Pythagorean fuzzy decision-making method based on hesitant fuzzy linguistic term sets (HFLTS), 2-tuple linguistic information, Pythagorean fuzzy sets (PFS), and VIKOR method to handle the SPO mechanism evaluation problem. Firstly, based on the analysis of SPO, the evaluation criteria system for SPO mechanism is established. Then, considering the uncertain information in the SPO mechanism evaluation process, the HFLTS is used to represent the linguistic judgments of experts under uncertainty. Next, the HFLTSs of different experts are converted into 2-tuple linguistic information and PFSs to model the overall judgments of different criteria. Finally, the extended VIKOR method is adopted to evaluate and rank different SPO mechanisms. A case study of SPO mechanism evaluation for the ground proximity warning system (GPWS) is used to demonstrate the effectiveness and feasibility of the proposed method, and the SPO mechanism that the autopilot being responsible for GPWS is evaluated by the proposed method to be optimal. Sensitivity and comparison analyses further confirm that the proposed method could provide reliable and reasonable SPO mechanism evaluation results. In conclusion, the proposed method presents a novel and effective way to evaluate and select appropriate SPO mechanisms.

Research on logistics of intelligent unmanned aerial vehicle integration system

As Unmanned Aerial Vehicle (UAV) is more and more frequently used in farming and logistics, civil and military alike, researches involving UAVs also starts to boom. In the civil field, UAV is generally flown in urban areas, so buildings are the main factors hindering the normal flight of UAV. Therefore, it is necessary to calculate an optimal flight path of UAV under constraints. The intelligent logistics UAV proposed in this paper can be used to replace special couriers to deliver small goods. It is a quadcopter integrated with a webcam, ultrasound Ground Proximity Warning System (GPWS), and is controllable through a mobile APP. Gradient descent algorithm, Linear Quadratic Regulator (LQR) and improved Proportion-Integral-Derivative (PID) controllers are applied in its flight control system, MATLAB and wavelet transform to handle fuzzy image. In addition, ant colony algorithm and adaptive strategies are used in the path planning process. As a result, it can detect surrounding obstacles in-flight, and the ground control station can receive feedback information and prepare for emergency operations.

DESIGN AND MODELLING OF GROUND PROXIMITY WARNING SYSTEM (GPWS) FOR TRAINING AID

Controlled flight into terrain (CFIT) is the most common type of aircraft crashes in the world of aviation today. Following the sheer volume of terrain collisions, there was an introduction of CFIT classification to enable the grouping into one category of all crashes involving aircrafts colliding with terrains. To avert CFIT accidents, the Ground Proximity Warning System (GPWS) was introduced onboard the aircraft for the flight crew to be aware of the moment the aircraft is approaching a ground terrain via automatic and very distinct acoustic warning. This paper presents a digital display ground proximity warning system as a teaching aid with audio prompt using ultrasonic sensor to produce forward distance from aircraft to obstacle ahead, height, inclination of aircraft in relation to its terrain beneath the aircraft and a digital computer interface for instrument visualization for better performance using graphic user interface (GUI) thereby enabling clearer understanding on GPWS. The Arduino IDE using Arduino sketch and C language were used on the Arduino Uno. The aircraft was integrated with different electronic modules which includes Arduino single board, Ultrasonic sensor, accelerometer and transceiver module, and all these uses the Arduino to read the signal from the sensor, processes and transmit to the base station wirelessly via radio frequency. Simulation results indicates that the responses of the models are a replica of the actual aircraft operations.

Recent Advancements in Controlled Flight into Terrain (CFIT) Prevention

A properly operating aircraft can experience a controlled flight into terrain (CFIT), which is a type of aviation mishap that causes the loss of life and property when it crashes into land or water. The aviation industry has been very concerned about CFIT accidents, and great efforts have been made to avoid them. The most current developments in CFIT prevention are summarised in this research paper. The study analyses existing CFIT prevention technologies, such as enhanced ground proximity warning systems (EGPWS), synthetic vision systems (SVS), and terrain awareness and warning systems (TAWS). It also looks at the possibility of cutting-edge technologies to improve CFIT prevention, such as automatic dependent surveillance-broadcast (ADS-B) and satellite-based augmentation systems (SBAS). The use of CFIT prevention technologies in different aircraft types is discussed in the paper, which also emphasises how effective these systems are at lowering CFIT accidents. It also examines the difficulties and constraints involved in putting CFIT prevention technologies into practice, such as the requirement for appropriate training and the expense of equipment. In order to further improve aviation safety, the paper emphasises the significance of ongoing study and development of CFIT prevention technologies. The use of these technologies can greatly lower the occurrence of CFIT accidents and increase the safety of air travel, especially when combined with pilot training and situational awareness.

Research on multi-functional logistics intelligent Unmanned Aerial Vehicle

As Unmanned Aerial Vehicle (UAV) is more and more frequently used in farming and logistics, civil and military alike, researches involving UAVs also starts to boom. In the civil field, UAV is generally flown in urban areas, so buildings are the main factors hindering the normal flight of UAV. Therefore, it is necessary to calculate an optimal flight path of UAV under constraints. The intelligent logistics UAV proposed in this paper can be used to replace special couriers to deliver small goods. It is a quadcopter integrated with a webcam, ultrasound Ground Proximity Warning System (GPWS), and is controllable through a mobile APP. Gradient descent algorithm, Linear Quadratic Regulator (LQR) and improved Proportion–Integral– Derivative (PID) controllers are applied in its flight control system, MATLAB and wavelet transform to handle fuzzy image. In addition, ant colony algorithm and adaptive strategies are used in the path planning process. As a result, it can detect surrounding obstacles in-flight, and the ground control station can receive feedback information and prepare for emergency operations.

Signs of Reincarnation: Exploring Beliefs, Cases, and Theory by James Matlock

At 1606:22, Clipper 759 informed the tower that it was ready for takeoff. At 1606:24, the local controller cleared the flight for takeoff, and at 1606:30, the first officer acknowledged the clearance. The acknowledgement was the last radio transmission received from Clipper 759.
 On July 8, 1982, Pan American World Airways Flight 759 (Clipper 759), a Boeing 727-235, N4737, was a regularly scheduled passenger flight from Miami, Florida, to Las Vegas, Nevada, with an en route stop at New Orleans, Louisiana. About 1607:57 central daylight time, Clipper 759, with 7 crewmembers, 1 nonrevenue passenger on the cockpit jumpseat, and 137 passengers on board, began its takeoff from runway 10 at the New Orleans International Airport, Kenner, Louisiana.
 At the time of flight 759’s takeoff, there were showers over the east end of the airport and to the east end of the airport along the airplane’s intended takeoff path. The winds at the time were gusty, variable, and swirling. Clipper 759 lifted off the runway, climbed to an altitude of between 95 feet to about 150 feet above the ground, and then began to descend. At 1608:57, the Ground Proximity Warning System (GPWS) activated and “Whoop whoop pull up whoop. . . .” was recorded. The airplane struck a line of trees about 2,376 feet beyond the departure end of runway 10 at an altitude of about 50 feet above the ground. The airplane continued on an eastward track for another 2,234 feet hitting trees and houses and then crashed into a residential area about 4,100 feet from the end of the runway.
 The airplane was destroyed during the impact, explosion, and subsequent ground fire. One hundred forty-five persons on board the airplane and eight persons on the ground were killed in the crash. Six houses were destroyed; five houses were damaged substantially.1,2 Moreover, nine people on the ground suffered severe injuries.
 The aircraft hit the ground with a considerable left bank angle, firstly hitting an oak tree with the left wing, cutting the power and the telephone lines mounted on poles, then destroying the houses of the Schultz family, the neighboring house, and a few others, and eventually cartwheeled and broke into pieces. Kerosene spilled from the ruptured tanks and ignited although there was a thunderstorm with heavy rain; three members of the Schultz family staying in their house were badly burned, one of them died in hospital. Among those killed on the ground—actually the first victim along the swathe of destruction caused by the crashing/impacting aircraft—was Jennifer Schultz, then eleven years of age, who was in the carport (perhaps was talking on the telephone, sitting on a swing there as she used to do) when disaster struck.
 On March 11th, 2008, in Bartlesville, Oklahoma, a girl, Rylann, was born to the O’Bannion family. Rylann appeared to be developing earlier than usual, but she showed some curious habits, e.g., for some time she kept sleepwalking. She started complaining that her hair touching her back hurt her back; she drew dramatic fits about putting on shirts. The clothing, she would complain, hurt her back, neck, and shoulders—it felt like her skin was burning.
 Referring to a photograph she mentioned time and again, she had been “bigger” than on that picture, a statement that didn’t make sense to her mother at that point in time. Eventually, at the age of three years and five months, again touching the topic of having been “bigger” before, she said: “Mommy, I died. I was in our backyard. It was raining. I was alone but I wasn’t scared. Then the rain shocked me. It was raining a lot. There was a loud noise, then the rain shocked me. I floated up to the sky then.”
 As the O’Bannion family subscribed to the Catholic faith, reincarnation was not a subject to consider. Over time, Rylann added new bits of memory; at the age of five she started talking about what happened to her “in heaven” after her death (meeting God and Jesus, and ‘Grandy Sally’ whom she never had met in reality), and that “you can choose to come back if you died before you were supposed to.” Once, out of the blue, she said “I remember the name of Jennifer.”

Methodic aspects of aircraft glide slope correction for prevention of CFIT category accidents during pre-landing descent

Aviation accidents of the category of controlled flight into terrain in world commercial aviation are included into three "killers" in aviation together with loss of control in flight (LOC-I) and runway excursions (RE). As a result of long-term research of this problem the methods of CFIT risk level reduction, pilot training and retraining programs were developed and put into practice. Also several generations of onboard ground proximity or obstacle warning systems were created (GPWS, EGPWS, TAWS), the disadvantage of which is a passive – advisory type of warnings. The conclusions of the commissions concerning the results of aviation accidents investigations indicate the cases of crew disregard of an alarm of a ground proximity warning system and possibility of a go-around procedure to make a missed approach. Despite the aviation community actions, accidents of this category continue to occur. Therefore, search of new methods and solutions of the controlled flight into terrain problem is necessary. One of the possible ways to resolve this problem is making proximity warning systems active and two-mode operative. The first one is some type of warning to the crew about approaching the boundaries of a safe maneuvering area during approach to land as well as the recommendations to avoid a glide path deviation. The second way is that if the crew members don`t take any actions with a warning on or crew actions are not effective enough, it is necessary to regain a glide slope with temporary pilot disengagement from a control loop.

An analysis of human factors in fifty controlled flight into terrain aviation accidents from 2007 to 2017

Introduction: Controlled Flight Into Terrain (CFIT) account for a considerable amount of fatalities when compared to other accident categories. Human factors are deemed significant contributory causes in these accidents. This paper aims to identify the human factors involved with aviation accidents that resulted in CFIT. Method: The study used the Human Factors Analysis and Classification System (HFACS) framework to determine the factors involved in 50 CFIT accidents from 24 counties over a 10 year period, i.e. 2007–2017. Interviews with five senior aviation safety experts were used to provide a better comprehension of the human factors affecting the flight safety. Results: The study identified 1289 individual causal and contributory human factors with unsafe actions and preconditions for unsafe actions being the main subcategories of the accidents. The study found that CFIT occur across a range of pilot experience and 44% of accidents occurred in cruise flight. Distraction, complacency and fatigue are all elements that flight crews may experience as contributors to CFIT during cruising. Conclusions: Human factors represent a major component of CFIT accidents. The analysis revealed a similar pattern of contributory and causal human factors across the various flight categories, with some noteworthy isolated variations. The prevalent factors were decision and skill-based errors along with communication, coordination and planning issues. Practical applications: Provision of specific CFIT awareness, pilot training focusing on improved decision-making and revision of basic flight skills, development of specific Global Positioning System routes for transiting high terrain areas are necessary to prevent CFIT accidents. Installation of Terrain Avoidance and Warning System and Ground Proximity Warning System and appropriate equipment training, specific CFIT Crew Resource Management training and improvement of organizational knowledge on the elements involved in CFIT are also recommended.

Evolution of the US Navy's collision avoidance systems (CAS) to future airborne capability environment (FACE)

The US Navy's collision avoidance systems (CAS) software product consists of five different system capabilities: ground proximity warning system (GPWS), terrain awareness warning system (TAWS), obstacle avoidance system (OAS), mid-air collision avoidance system (MCAS), and auto-recovery CAS (AutoCAS). GPWS provides directive controlled fight into terrain (CFIT) protection against fight into level or descending terrain. TAWS provides directive CFIT protection against level, descending, and rising terrain. OAS provides directive protection and situational awareness, through a display, of man-made obstacles. MCAS provides passive protection and awareness of other airborne aircraft. AutoCAS provides active protection by interacting with the avionics system to take control of the aircraft to automatically avoid impact with terrain, obstacles, and/or aircraft. For each capability, the software product provides advisories or directive aural warnings and visual indications to the aircrew. The goal is to maximize protection and minimize nuisance warnings to ensure aircrew trust the system in a dynamic tactical environment [1]. Balancing protection with nuisance warnings is done by embedding an aircraft-specific performance model into the CAS software product.

DID TECHNOLOGY IMPROVE SAFETY? AN EMPIRICAL STUDY OF CONTROLLED FLIGHT INTO TERRAIN ACCIDENTS

Aviation safety has been affected greatly by technological improvements. A series of Ground Proximity Warning Systems (GPWSs) were developed to prevent accidents during Controlled Flight into Terrain (CFIT). This study analyzed the role of GPWS (or Enhanced GPWS, EGPWS) in flight safety history to determine how effective GPWS/EGPWS was in terms of preventing CFIT. The result showed a substantial increase in CFIT accidents due to the rapid growth of aviation development. This situation improved after the mandatory installation of GPWSs in commercial aircraft. However, the legal requirement did not apply to all general aviation. Most CFIT accidents have involved general aviation aircraft that do not have GPWS/EGPWS installed on board. Thus, the mandatory requirement should apply to all civil aircraft. CFIT accidents have also been reduced considerably in developed countries whereas they remain a major issue in developing countries.

항공기 충돌 회피 경고 알고리듬 연구

항공기 사고 중에서 주요 원인 중 하나인 조종상태 지상충돌(Controlled Flight Into Terrain, CFIT)을 해결하기 위하여 대지 접근 경고 장치(Ground Proximity Warning System, GPWS)를 사용하여 항공기 아랫부분의 지형에 대해서 지형충돌 경고를 출력한다. 이러한 대지 접근 경고 장치도 적시에 경고가 발생하지 않아 많은 문제가 있었다. 본 논문에서는 비행 상태와 지형정보를 이용하여 속도가 빠르고, 고기동을 하는 전투기에 대해서 보다 효율적인 지형/장애물 충돌 회피 경고 알고리듬을 개발하였다. 이 알고리듬에는 조종사의 반응시간을 포함하여 항공기의 지연시간을 고려하였고, 일련의 검증을 통해 실제 탑재 가능한 알고리듬을 제시하였다. CFIT(Controlled Flight Into Terrain) is one of the major causes of aircraft accidents. In order to solve this problem, GPWS(Ground Proximity Warning System) is used to generate terrain collision warning using the distance between the aircraft and the underneath ground. Since the GPWS uses the vertical clearance only, it frequently generates false warnings. In this study, a terrain/obstacle collision avoidance warning algorithm was developed for fast flying and highly maneuvering fighters using the flight status and the geographic information. This algorithm condsiders the overall delay in the aircraft reactive motion including the pilot's reaction time. The paper presents a detailed logic and test methods.

Researches on Simulation and Validation of Airborne Enhanced Ground Proximity Warning System

In this paper, enhanced ground proximity warning simulation and validation system is designed and implemented. First, based on square grid and sub-grid structure, the global digital terrain database is designed and constructed. Terrain data searching is implemented through querying the latitude and longitude bands and separated zones of global terrain database with the current aircraft position. A combination of dynamic scheduling and hierarchical scheduling is adopted to schedule the terrain data, and the terrain data can be read and delete dynamically in the memory. Secondly, according to the scope, distance, approach speed information etc. to the dangerous terrain in front, and using security profiles calculating method, collision threat detection is executed in real-time, and provides caution and warning alarm. According to this scheme, the implementation of the enhanced ground proximity warning simulation system is realized. Simulations are carried out to verify a good real-time in terrain display and alarm trigger, and the results show simulation system is realized correctly, reasonably and stable.

Modeling Operator Responses to Alerts

Two models were evaluated with respect to Aviation Safety Reporting System incident reports related to the Ground Proximity Warning System. These reports were examined for consistency with the first model, which was found to be invalid. A second model was developed to better explain the data, and was found to be consistent with the data and with previous results related to responses to alerting systems.

Modeling Operator Responses to Alerts

Two models were evaluated with respect to Aviation Safety Reporting System incident reports related to the Ground Proximity Warning System. These reports were examined for consistency with the first model, which was found to be invalid. A second model was developed to better explain the data, and was found to be consistent with the data and with previous results related to responses to alerting systems.

Ecological Approach to Support Pilot Terrain Awareness After Total Engine Failure

Terrain awareness enhancing avionics, such as Synthetic Vision Systems and the Enhanced Ground Proximity Warning System, have been developed to reduce the number of controlled flight into terrain accidents. The protection these systems offer, however, is far from optimal. Synthetic Vision Systems only provide pilots with perceptual data, and leave all cognition and interpretation of data to the pilot. With Enhanced Ground Proximity Warning Systems the opposite is true. Here, pilots are only confronted with compelling advisories and commands without the underlying data and rationale. This paper presents a display system, the Emergency Landing Guidance System, that visualizes the functional of surrounding terrain, adopting an ecological interface design approach. The potential benefits of this approach are demonstrated with the case of locating and approaching a suitable landing area after sudden complete engine failure. To evaluate the effect of the new display on pilot terrain awareness, an experiment was conducted in a fixed-base flight simulator. Results show that the new display supports pilot terrain awareness much better than present terrain avoidance systems, i.e., pilots better understand the meaning of the terrain in relation to their goals and constraints. However, pilots also operated more closely to the limits of performance, thereby negatively affecting the metrics for safety.

Ecological Interface Design for Terrain Awareness

Advanced terrain warning systems, such as the enhanced ground proximity warning system, and safety-enhancing displays, like the synthetic vision system, have proven to play an important role in reducing the number of controlled flight into terrain accidents. Research indicated, however, that terrain collisions may still occur for aircraft equipped with these systems. Synthetic vision allows for perception of the environment, but lacks properties to support understanding and extrapolation of the perceived data. A terrain warning system provides elementary meaning to the environment, but is not well integrated into synthetic vision displays. To further increase terrain awareness and, ultimately, eliminate terrain collisions, synthetic vision should be integrated with a terrain awareness functionality that allows the pilot to be continuously informed about how the external constraints (imposed by the terrain) relate to the internal aircraft constraints (e.g., climb performances). Based on that information, pilots can judge for themselves what an obstacle actually means to them in terms of possibilities to fly over it, and if not, what the alternatives for action are. In this article, the paradigm of ecological interface design is used to analyze the aircraft manual control task in the vertical plane and to develop a more meaningful interface for (vertical) terrain awareness. An abstraction hierarchy is presented, developed for the task of guiding an aircraft through a terrain-challenged environment. The design and experimental evaluation of a vertical situation display are discussed, enhanced with ecological overlays to increase terrain awareness.

IRI Achievement Award Address: An Engineer Looks at Innovation

OVERVIEW:The development and commercial acceptance of the Ground Proximity Warning System was the culmination of years of product innovation and improvement by a small group of Honeywell engineers. Its success illustrates the soundness of such traditional innovation “rules” as “encourage your mavericks,” “get a champion,” “keep a low profile,” and “minimize the risks.”

Markov Model of Terrain for Evaluation of Ground Proximity Warning System Thresholds

Astatistical model ofterrainwasdevelopedtoestimatetheprobabilityofacontrolled eightintoterrainaccident followingaground proximitywarningsystem(GPWS)alert. The terrain model wasderived froman actual terrain database and used to create a Markov chain simulation. With this simulation the probability of terrain impact was computed as a function of terrain type and aircraft trajectory proele. Contours of collision probability were then generated and plotted against current alerting thresholds, illustrating how threshold placement maps into safety. Example results for the GPWS excessive descent rate alerting mode are provided. Following a warning and the subsequent pilot reaction delay and pull-up maneuver, the probability of collision with relatively e at terrain is less than 1 £ 10i 8 for high descent rates. In steep, rapidly changing terrain, the probability of collision following an alert increases to more than 0.01. A simple modie cation of alerting thresholds would not resolve this problem because of a resulting higher rate of nuisance alarms, as shown quantitatively by a performance tradeoff curve. Potential performance improvements through decreased response time or increased maneuvering load factor are also quantie ed.

Examination of Part 135 Controlled Flight into Terrain Accidents as a Basis for Enhanced Ground Proximity Warning Systems

In 1998 the Federal Aviation Administration (FAA) proposed the installation of Enhanced Ground Proximity Warning devices (EGPWS) in all turbine powered aircraft with six or more passenger seats, operating under Federal Aviation Regulation Part 135, to reduce “Controlled Flight Into Terrain” (CFIT). CFIT accident experience of Part 135 operations has not been evaluated by the FAA. We analyzed all commuter and charter aircraft crashes of this type using NTSB aviation accident data from 1983 to 1998. There were 15 crashes with CFIT criteria. We asked 15 experienced pilots to examine the narratives of the crashes and to estimate the probability that EGPWS would have allowed the crew to avoid these crashes. Based on the ratings, the median probability that Part 135 crashes would be avoided using EGPWS is 58%. Human factors issues associated with EGPWS are discussed.

Alarm Related Incidents in Aviation: A Survey of the Aviation Safety Reporting System Database

Today's aircraft cockpits are complex environments requiring pilots to monitor a large number of automated displays and alarm systems. A recent investigation of alarm-related incidents in Naval aircraft found high rates of alarm-related problems, particularly false and missed alarms. For the current research, we analyzed a sample of narrative accounts taken from the National Aeronautics and Space Administration's Aviation Safety Reporting System (ASRS). We categorized and tabulated the data according to alarm problem (false, missed, or other), aircraft type, avionics (alarm system), and flight phase. Our findings indicated that alarm-related incidents are still quite common in civil aircraft. Furthermore, most alarm-related incidents occur during the approach phase of a flight, and are likely to involve the Ground Proximity Warning System (GPWS) or the Traffic Collision Avoidance System (TCAS). We recommend further empirical research to understand alarm-related problems, particularly the cry-wolf effect.