• 대한기계학회논문집B
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• 제26권8호
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• pp.1153-1163
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• 2002

A transient analysis on temperatures of fuel and oil in hydraulic and lubrication systems in an aircraft was studied using the finite difference method. Numerical calculation was performed by an explicit method with modified Dufort-Frankel scheme. Among various missions, air superiority mission was considered as a mission model with 20% hot day ambient condition in subsonic region. The ambience of the aircraft was assumed as turbulent flow. Convective heat transfer coefficient were used in calculating heat transfer between the aircraft surface and the ambience. For an aircraft on the ground, an empirical equation represented as a function of free-stream air velocity was used. And the heat transfer coefficient for flat plate turbulent flow suggested by Eckert was employed for in-flight phases. The governing equations used in this analysis are the mass and energy conservation equations on fuel and oils. Here, analysis of fuel and oil temperature in the engine was not carried out. As a result of this analysis, the ground operation phase has shown the highest temperature and the largest rate of temperature increase among overall mission phases. Also, it is shown that fuel flow rate through fuel/oil heat exchanger plays an important role in temperature change of fuel and oil. This analysis could be an important part of studies to ensure thermal stability of the aircraft and can be applicable to thermal design of the aircraft fuel system.

• 한국항행학회논문지
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• 제3권1호
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• pp.69-90
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• 1999

한국의 공역은 매우 제한적이나 공역사용자들이 많고 특히 군기관의 전용 공역이 많이 설정되어 있고 이 전용 구역을 민간항공기가 사용할 수 기회가 매우 제한적이다. 그러나 항공수요가 계속 증가하므로 공역의 활용도를 높혀 항공수요에 적극적으로 대처하기 위하여 관련 사용자들간의 적극적인 협조가 요구되고 있다. 항로 이외의 대부분이 군기관의 군훈련공역과 제한구역인데, 여기서는 민간항공기에게 이 공역에 대한 활용도를 높히는 방법과 그로 인하여 민간항공에 경제적으로 어느 정도의 혜택이 주어지는지를 보여준다.

• 한국항행학회논문지
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• 제21권3호
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• pp.230-242
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• 2017

국회는 2017년 3월 30일 제조물책임법 일부개정법률안을 국회본회의에서 통과로 인해 제조물 소송비용의 부담이 대폭 증가할 것으로 예상된다. 정부법무공단은 2017년 3월 14일자로 수리온 헬기 4호기 추락사고에 대하여 군용항공기제작사인 한국항공우주산업(주)와 한화테크윈에게 하자담보책임과 채무불이행, 제조물책임법으로 손해배상 청구소송을 제기하였다. 미국은 1970년대 중반에 제조물책임보험이 적용되지 않는 군용항공기제작사의 책임한계에 대하여 학계와 법조계에서 많은 논란이 있었으며, 이러한 문제를 해결하기 위하여 도입된 법리가 정부계약자항변(GCD; government contractor defense)이라는 법 이론이며, GCD가 확립된 대표적인 사례는 Boyle v. United Technologies Corporation이다. 군용항공기 제작사가 높은 제조물책임보험을 들 수 없고, 방산원가에도 제조물책임보험료를 반영시키지 않는 현실에서 우리나라의 군용항공기제작사는 사고 시 손해배상으로 인한 위기에 직면하고 있는 것이 현실이다. 우리나라도 미국의 정부계약자 법리를 연구하여, '국가를 당사자로 하는 계약에 관한 법률'을 개정하는 방안을 찾아야 할 것이다.

• 한국항공운항학회지
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• 제28권1호
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• pp.115-121
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• 2020

Recently avionics equipment and its integration are most important part for implementing high performance aircraft system. This trends are emphasized in the military or special purpose aircraft development program. Flight Test Bed Aircraft (hereafter FTB A/C) - by modified commercial aircraft - was key solution to verify function and performance of avionics system for complex aircraft development program for a while, but there are no experience to use it in domestic airspace of ROK. This paper would like to address what act and regulation is necessary to perform flight operation of FTB A/C with keeping a airworthiness and airspace control policy. and then willing to propose what do we do for improving aviation industry.

• 한국항공운항학회지
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• 제21권4호
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• pp.11-16
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• 2013

Airworthiness certification is a repeatable process implemented to verify that a specific aircraft can be safely maintained and operated within its approved flight envelope. Airworthiness certification activity for the FA-50 aircraft has been performed according to the Airworthiness Certification Criteria, issued in 2011 by DAPA. It is a right time to study the application of those existing ACC process and tools to the hypothetical modification aircraft. This paper describes airworthiness engineers view of the integrated activities required to substantiate the modified aircraft performance. The compliance methods applicable to the airworthiness certification criteria is also suggested. It will be useful for the establishment of the future Korea modified military aircraft's ACC with the risk assessment and methods of compliances tailored to the legacy aircraft.

• 한국항공운항학회지
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• 제26권4호
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• pp.101-109
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• 2018

In order to predict the future needs of the aircraft repair parts, each military group develops and applies various techniques to their characteristics. However, the aircraft and the equipped weapon systems are becoming increasingly advanced, and there is a problem in improving the hit rate by applying the existing demand prediction technique due to the change of the aircraft condition according to the long term operation of the aircraft. In this study, we propose a new prediction model based on the conventional time-series analysis technique to improve the prediction accuracy of aircraft repair parts by using machine learning model. And we show the most effective predictive method by demonstrating the change of hit rate based on actual data.

• 한국군사과학기술학회지
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• 제20권5호
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• pp.597-607
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• 2017

The general control method for Anti-lock Brake System(ABS) is that the wheel slip ratio is observed and the braking force is controlled in real time in order to keep the wheel slip ratio under the value of the best slip ratio. When a wheel runs on the state of the best slip ratio, the ground friction of the wheel approaches the highest value. The value of best slip ratio, theoretically, is known as the value between 10 and 20 % and it is dependant on the ground condition such as dry, wet and ice. It is an important parameter for the braking performance and affects the braking stability and efficiency. In this thesis, an experimental method is suggested, which is a reliable way to decide the best slip ratio through dynamo tests simulating aircraft taxiing conditions. The obtained best slip ratio is proved its validity by results of aircraft taxiing tests.

• 한국군사과학기술학회지
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• 제14권5호
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• pp.788-797
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• 2011

This paper analyzes the accuracy on the approach and landing of aircraft to an airport through comparison with airbase Precision Approach Radar and aircraft track data of DGPS equipped in aircraft. The proposed analysis result could be a basis for verifying the possibility that DGPS can be utilized in Airbase precision approach and landing. Position identification capability of widely used commercial DGPS is fairly accurate on latitude and longitude, while there is a slight error for being used in an airbase accurate approach and landing of Category I precision when it comes to altitude. Thus, we tested accuracy by analyzing actual flight track data of high performance aircraft to verify the accuracy of the airbase approach and landing using DGPS. Through the research, we developed instrumentation to compare PAR track data with DGPS track data, which can be used in reducing the number of PAR verification Flight utilizing it as a system measuring PAR accuracy at PAR installation phase.

• 한국항공운항학회지
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• 제26권2호
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• pp.132-138
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• 2018

Aviation safety requires systematic national attention and management because aircraft accident produce greater undesired social impact, economical damage, and declining national credibility compare to other transportation accident. Specially, Republic of Korea has highly increased risk of air accident as a major air transportation point having small aerospace, connecting pacific ocean and Asia, and explosively increased air traffic produced by economical growth, operating numerous military aircraft for the South and North Koreas' confrontational situation. Also, greatly increased domestic and oversea air travels by Koreans and foreigners as well as air freight based on heightened Korea's national power, launching new low cost carriers, and popularized leasure aviation have produced large amount of aviation needs in various fields. However, national aviation safety management system gratifying increased aviation needs and aircraft operations is seem to be slow in progress. This paper will show optimized measures utilizing private, governmental, and military resources to prevent aircraft accident under circumstances of limited budget and an favorable conditions, then will propose several action items.

• 한국국방경영분석학회지
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• 제30권2호
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• pp.96-107
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• 2004

This paper deals with $\ulcorner$Requirement Decision Model for Repair Parts supplied by the Government$\lrcorner$ which is to reduce Aircraft Contract Maintenance Cost. It aims to find solutions to the fundamental problems of the Aircraft Contract Maintenance System. Under the current Aircraft Contract Maintenance System, it is hard to forecast the exact demand of repair parts, so support rate of Repair Parts supplied by the Government is restricted under 50 percent. It is inevitable to purchase Repair Parts from the firm with much higher price than those of Government source. However, absence of fixed demand pattern makes it difficult to improve accuracy of demand forecast. As a solution to these problems, this model prevents a cost increase due to the unit price difference between Repair Parts supplied by the Government and Repair Parts purchased by the Firm. It also reflects demand characteristics of each repair part, and prevents continual stock increase by setting an upper limit on the amount of Repair Parts supplied by the Government. The effectiveness of this model is verified by empirical analysis using the latest raw data. By applying this model to real situation, we expect to reduce about 4 billion won every year.