• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.47-55
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• 2021

When an abnormal landing occurs, aircraft structures should be designed to guarantee occupants survivability without preventing egress. To find out fire root causes at crash, lots of fixed aircraft crash tests were conducted. Appropriate crash load factors were established with the comprehension of structural behavior based on dynamic analysis and investigation of human tolerance. Cargo restraint criteria were set up considering passengers safety and operational cost while analyzing past cargo aircraft accident data using a probabilistic approach. Reviewing results of past crash tests, current crash landing load factor was appreciated physically, medically, and economically.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1990.10a
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• pp.208-211
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• 1990

• Journal of the Korean Society for Aviation and Aeronautics
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• v.12 no.3
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• pp.1-12
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• 2004

When a straight-in landing from an instrument approach using ILS or VOR/DME is not possible or desirable because of topographical reason or bad weather, a circling approach maneuver is initiated by the pilot to align the aircraft with a runway for landing. Visual contact with the runway is necessary while conducting a circle to land maneuver. This research is to develop a new warning system based on a conventional marker system which alerts pilots to watch out for exceeding the circling approach area. The airborne system also uses the same receiver unit without any new installations. The objective of this research is to design and develop a Yagi antenna in a special form. The research includes computer simulations to determine the size of antenna radiation pattern and to compute an expected flight path in case of alarm to validate effectiveness of the system.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.888-896
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• 2023

When an aircraft is landing, it is expected that the aircraft will follow a specified approach procedure and then land at the airport. However, depending on the airport situation, neighbouring aircraft or the instructions of the air traffic controller, there can be a deviation from the specified approach. Detecting aircraft approach patterns is necessary for traffic flow and flight safety, and this paper suggests clustering techniques to identify aircraft patterns in the approach segment. The Gaussian Mixture Model (GMM), one of the machine learning techniques, is used to cluster the trajectories of aircraft, and ADS-B data from aircraft landing at the Gimhae airport in 2019 are used. The aircraft trajectories are clustered on the plane, and a total of 86 approach trajectory patterns are extracted using the centroid value of each cluster. Considering the correlation between the approach procedure pattern and overshoots, the distribution of overshoots is calculated.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.1
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• pp.67-74
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• 2009

In general, the lunar landing stage can be divided into two distinct phases: de-orbit and descent, and the descent phase usually comprises two sub-phases: braking and approach. And many optimization problems of minimal energy are usually focused on descent phases. In these approaches, the energy of de-orbit burning is not considered. Therefore, a possible low perilune altitude can be chosen to save fuel for the descent phase. Perilune altitude is typically specified between 10 and 15km because of the mountainous lunar terrain and possible guidance errors. However, it requires more de-orbit burning energy for the lower perilune altitude. Therefore, in this paper, the perilune altitude of the intermediate orbit is also considered with optimal thrust programming for minimal energy. Furthermore, the perilune altitude and optimal thrust programming can be expressed by a function of the radius of a parking orbit by using continuation method and co-state estimator.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.264-271
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• 2011

ILS(Instrument Landing System) is the international standard system for approach and landing guidance. ILS was adopted by ICAO(International Civil Aviation Organization) in 1947 and is currently being used in commercial systems. To design the digital transmitter and receiver modules that can be mounted in the integrated ILS, we propose the digital design methods of digital double AM modulator and demodulator using FPGA chip, DDS(Direct Digital Synthesizer) for generation of sampling clock, demodulator of DDC(Digital Down Converter) structure, and spectrum analyzer using DSP chip. We demonstrate the efficiency of the proposed design method through experiments using developed transmitter and receiver modules. This system can be used as a high-performance commercial system.

• Advances in aircraft and spacecraft science
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• v.7 no.2
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• pp.91-113
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• 2020

This paper analyzes the terminal descent phase of a space lander on a surface of a celestial body. A multibody approach is adopted to build the physical model of the lander and the surface. In this work, a legged landing gear system is considered. Opportune modelling of the landing gear crashbox is implemented in order to accurately predict the kinetic energy. To ensure the stability of the lander while impacting the ground and to reduce the contact forces that arise in this maneuver, the multibody model makes use of a co-simulation with a dedicated control system. Two types of control systems are considered; one with only position variables and the other with position and velocity variables. The results demonstrate the good reliability of modern multibody technology to incorporate control algorithms to carry out stability analysis of ground impact of space landers. Moreover, from a comparison between the two control systems adopted, it is shown how the velocity control leads to lower contact forces and fuel consumption.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.2
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• pp.14-24
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• 2021

This study aims to examine probable human errors when landing an airplane by the use of SHERPA(systematic human error reduction and prediction approach) and propose methods for preventing the predictive human errors. It has been reported that human errors are concerned with a lot of accidents or incidents of an airplane. It is significant to predict presumable human errors, particularly in the operation mode of human-automation interaction, and attempt to reduce the likelihood of predicted human error. By referring to task procedures and interviewing domain experts, we analyzed airplane landing task by using HTA(hierarchical task analysis) method. In total, 6 sub-tasks and 19 operations were identified from the task analysis. SHERPA method was used for predicting probable human error types for each task. As a result, we identified 31 human errors and predicted their occurrence probability and criticality. Based on them, we suggested a set of methods for minimizing the probability of the predicted human errors. From this study, it can be said that SHERPA can be effectively used for predicting probable human error types in the context of human-automation interaction needed for navigating an airplane.

• Progress in Superconductivity and Cryogenics
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• v.24 no.2
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• pp.27-38
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• 2022

Urban air mobility (UAM) has recently attracted lots of attention as a solution to urban centralization and global warming. Electric vertical take-off and landing (eVTOL) is a concept that emerges as one of the promising and clean technologies for UAM. There are two difficult challenges for eVTOL aircraft to solve. One is how to improve the weight efficiency of aircraft, and the other is how to complete long-range missions for UAM's flight scenarios. To approach these challenges, we propose a consolidated concept design of battery-fuel cell hybrid tiltrotor aircraft with a liquid hydrogen (LH₂) fuel tank. The efficiency of a battery-fuel cell hybrid powertrain system on the designed eVTOL aircraft is compared to that of a battery-only powertrain system. This paper shows how much payload can increase and the flight scenario can be improved by hybridizing the battery and fuel cell and presenting a detailed concept of a cryogenic storage tank for LH₂.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.403-410
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• 2015

ADS-B can provide high accurate position information and faster update rate than Radar system and it is a technique that can supplement or replace the Radar. Recently ADS-B has been applied to the actual aircraft operation because to increase air transportation traffic and required to high accurate surveillance. In this study, we surveyed analysis of position deviation distribution analysis and received actual ADS-B trajectory data for conformed precise surveillance on the near airport area using ADS-B message. For that, we received the precision instrument approach ADS-B trajectory data using instrument landing system, and can analyse about target deviation distribution on the final approach segment about precision instrument approach. The result of analysis is mean distance of target deviation -0.04 m and standard deviation 6.71 m on between ADS-B target and extended runway centerline. Also that is to conformed the ADS-B message trajectory available to provide relatively exact surveillance information.