• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.64-74
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• 2021

Unmanned Aircraft Systems (UAS) are rapidly emerging not only as a key military power, such as surveillance and reconnaissance for military purposes but also as a new air transportation means in the form of Urban Air Mobility (UAM). Currently, airworthiness certification is carried out focused on the verification of technical standards for flight safety suitability of aircraft design in accordance with the Military Aircraft Flight Safety Certification Act and does not employ the model for operational risk assessment for mission areas and airspace. In this study, in order to evaluate the risk of the mission area from the perspective of the UAS operator, a risk assessment simulation has been conducted by applying the Specific Operations Risk Assessment (SORA) model to the operating environment of the Korean military UAS. Also, the validity of the SORA model has been verified through the analysis of simulation results, and a new application plan for airworthiness certification of the military unmanned aerial system has been presented.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.108-117
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• 2023

Thus far, a mission software component of the KT-1 military fixed-wing aircraft for overseas export has been developed through international joint development with foreign companies. The reliability of the software component could be certified by complying with the development environment and procedures of foreign companies based on DO-178B. However, recently, DO-178C certification is required for overseas exports, and reliability tests to comply with the weapon system software development guidelines are required for domestic military forces. In this paper, we describe the problems in obtaining domestic airworthiness certification in the international joint development of a previously developed KT-1 export-typed aircraft system integration project. To this end, we find a solution to comply with both DO-178C and the Weapon System Software Development and Management Manual and provide the optimal software reliability test method.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.42-48
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• 2009

There are a number of factors affecting the continued airworthiness of composite structure. Unlike metal structure, damages made in manufacturing processes or maintenance repair procedures need to be considered. The different levels of degradation and damage, which may occur, must be considered for structural substantiation of static strength, stiffness, flutter, and damage tolerance. This can start with an evaluation of environmental effects for the particular composite material. Matrix-dominated composite properties, such as compressive strength, are most sensitive to moisture absorption and temperatures. Static strength substantiation includes the smaller damages that will not be detected in production or maintenance inspection while damage tolerance addresses larger damages that need to be repaired once discovered. In this paper, we intend to list the airworthiness regulations and advisory circular that are deemed closely related to the certification of composite airplanes.

• Journal of Aerospace System Engineering
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• v.12 no.5
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• pp.24-31
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• 2018

The objectives of this study is to carry out Bird strike analysis and tests of a blade antenna of aircraft. FEMs (Finite Element Models) were created for the analysis, while dummy and real antennas were used for the bird strike tests. In the analysis, birds were modeled with SPH (Smooth Particle Hydrodynamics) method, and the behaviors of the bird, antenna, and joint structure between antenna and aircraft fuselage were simulated with the FSI (Fluid-Structure Interaction) method. After the bird strike test was performed, the results of the analysis and test showed that they had a positive relationship. The damage of antenna and bolted joint was checked, and the structural integrity of the airframe was proved.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.7
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• pp.642-652
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• 2009

Most of lap jointed aircraft structures encounter the fretting damages, which provoke fretting cracks prematurely and lead to significant reduction of fatigue life. In the case of ageing aircrafts especially, this fretting fatigue problem is a fatal threat for the safety and airworthiness. Recently, as the service life extension program(SLEP) of ageing aircrafts has become a hot issue, the prediction of fretting fatigue life is also indispensable. On these backgrounds, a series of experimental tests of fretting fatigue on bolted lap joint specimens, were performed. And the fretting crack initiation and propagation life of each specimen were evaluated using existing and newly proposed prediction models with the fretting parameters obtained from the FEA results for elasto-plastic contact stress analyses. The validations of prediction models were also discussed, comparing the prediction results with experimental test ones.

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.279-284
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• 2013

Among the phases of flight operations pilots feel much pressure in landing segment. There is a number of factors affecting landing safety while pilots reduce aircraft speeds and make a touchdown and stop completely. If runway length is sufficient for landing, there maybe is no problem. But it is not the case all the time. So it is necessary to confirm whether landing performance is within limits or not. Required landing distance is actual landing distance demonstrated by flight test pilot plus allowances for average airline pilots. FAR(Federal Aviation Regulations) AFM certification is based upon manual landing for dry and wet runway. Other runway conditions are not the certification basis. JAR dictates even contaminated/slippery runway is included by prescribed allowances. Automatic landing is not certification basis, so actual landing distances are provided. In this paper I would like to analyze distance allowances included in each type of runway condition. In addition there is no regulation about allowances for specific runway condition, I would suggest adequate allowances for that case.