• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.12
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• pp.1482-1487
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• 2009

In this study statistical analysis was performed for NDI(Non-Destructive Inspection) results of F100 engine front seal support assembly. NDI results can be statistically considered as Quantal Response Data. It is found that the suitable probability distribution to the failure data is normal distribution through MLE(Maximum Likelihood Estimation) of the Quantal Response Data. Moreover, Cumulative Distribution Function, failure rate function and B-Life are calculated on the supposed distribution.

• Journal of Advanced Navigation Technology
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• v.22 no.4
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• pp.264-270
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• 2018

In recent years, It is required to verify software reliability according to DO-178, which announced by radio technical commission for aeronautics (RTCA) and recognized by the Federal Aviation Administration (FAA), for civil aircraft developed or intended to fly in the United States or Europe. This is because the reliance on software in each field is deepening, and the efforts for improvement of software reliability have been made first in civil aviation field where economic and social impacts are catastrophic in the event of an accident. In this paper, we have identified some issues to be considered for requirements-based reliability verification required by DO-178 to improve software reliability and present the major elements of the present weapon system acquisition procedure of DAPA for each stage. In addition, we analyzed the results of applying the identified main check factors to a domestic aircraft development project based on the information accumulated in overseas aircraft development projects. As a result, we have shown that it is possible to verify requirements-based software reliability according to DO-178 by adding key checkpoints to the current weapon system acquisition procedure and providing objective inspection criteria.

• Journal of Advanced Navigation Technology
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• v.28 no.3
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• pp.254-261
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• 2024

Accurate guidance during landing and take-off is important, and instrument landing system (ILS) has been used for stability and verification. Regular inspections are conducted for stable operation, and there is research to perform inspection using drones in addition to ground vehicles and measurement aircraft. Using SDR and single board computer, which can receive wide frequency range, we designed a small system that receives and processes localizer signals through GNU Radio. To check signal processing characteristics through GNU Radio, we simulated with MATLAB Simulink and confirmed the theoretical values. Difference in depth of modulation (DDM) and approach angle can be calculated when the aircraft enters the runway. And GNU Radio implemented real-time signal processing wirelessly using transmission control protocol (TCP). This gives the results within the error of 0.5% when the aircraft entered the runway center line and 0.27% for the angle of 1° degree. Compared to the inspecting and maintaining ILS signals using aircraft or ground vehicles, it is possible to implement a receiving system using small SDR that can be mounted for drone.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.791-796
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• 2012

Small gas turbine engines are used in aircraft as an auxiliary power unit (APU) to supply compressed air to start the main engine and for emergency electricity. When an aircraft is operating in an environment in which sand and dust is present in the ambient air, the engines as well as the APU ingest the sand and dust. This causes erosion of the engine and a degradation in its performance. The present study investigated the effect of sand and dust ingestion on small gas turbine engines. The concentration of sand and dust was $4.4{\times}10^{-5}kg$ per unit kg of air, which follows the specification in MIL-E-8593. The test was conducted for 10 h, and the engine performance before and after the test was compared. In addition, a tear-down inspection was conducted to examine the erosion patterns of sub-components such as the impeller and turbine wheel.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.306-313
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• 2011

The damage tolerance analysis is required to guarantee the structural safety and the reliability for aircraft components. The damage tolerance method, which evaluate the life considering the initial crack, considers a fatigue design model of the aircraft main structure. The fatigue crack growth life should be calculated in damage tolerance analysis and the inspection time to define the replacement cycle. In this paper, the damage tolerance analysis is performed for a turbine wheel which has complex geometry. The equation of the stress intensity factor for complex geometry is hard to know, so that they are usually processed by finite element analysis which takes long time. To solve this problem, the stress intensity factors at specified crack are obtained by the FEA and the crack growth life is evaluated using the surrogate model which is generated by the regression analysis of the FEA data. From the results, the efficiency of the crack growth life calculation and the damage tolerance analysis could be increased by taking the surrogate model.

• Journal of Advanced Navigation Technology
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• v.19 no.3
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• pp.175-181
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• 2015

Method establishment needs for recent shortening the flight path, fuel reduction, reduction of the flight delay time, increase of the route capacity like as relieve congested airspace and solving future demand. However, As the existing conventional navigation systems is impossible to be resolved. Hereupon, SBAS has been developed with using the GNSS. ICAO has recommended that SBAS need to be operated with aircraft operation from 2025, korea is also developing KASS in accordance with the recommendation. In this paper, before the 2022 KASS will be completed, KASS can be expected using for flight test and inspection as analyzing KASS flight test and relative specifications.

• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.105-114
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• 2016

The world is currently confronted with regional conflicts among nations that seek to protect their territory. The associated counter-terrorism activities and international business flows can be increased through airworthiness-recognition tasks that are related to aircraft exports, dispatch troops, and overseas bases. It is important to establish airworthiness-recognition processes between foreign military authorities to minimize the potential for sovereign national positions and responsibilities. For this study, the military airworthiness recognition between recognition partners was surveyed to secure flight safety for the development and operation of aircrafts. The analysis of the U.S. and European Military Authority Recognition Questionsets (MARQs) in this paper introduces the rules, inspection capabilities, production process, and certification of the airworthiness authority. The regulatory activities, which are required by the Korea Military Airworthiness Authority (MAA) with respect to foreign MAAs, can be reduced by the implementation of the MARQ.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.522-525
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• 2019

To overcome the limitation of ground inspection for Navigational Aid, Korea Airport Corporation (KAC) developed a drone system for Navigational Aid inspection. This drone system has the advantage that they can inspect the air radio signal at the perspective of user (aircraft). Since drones have more free flight paths and easier control of flight speeds compared to aircrafts, drones can check sections of suspected airborne radio wave distortions at desired paths and speeds. Recently, with the acceleration of the development around the airport, there is a concern about the deterioration of the quality of radio signal of Navigational Aid. In order to analyze radio distortion of Navigational Aid, a radio wave environmental survey was conducted using drones. When the signal received by each flight path of the drone was measured, the origin of the reflected wave was identified by analyzing the section in which the radio signal was distorted.

• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.8-19
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• 2019

Pilots have used checklist as a valuable tool to improve aviation safety and to reduce human error. A checklist however is too complex for a student pilot to use with less flight experience or time than a commercial pilot. It is agreed upon such complex checklist be a factor to threaten aviation safety for student pilots. This paper has focused on a checklist by dividing it into a couple of basic three flight procedures. Making exploratory case study of student pilots, researchers could analyze the correlation between checklist factors and those of human errors. First of all, it was necessary for student pilots to be educated professional knowledge regarding aircraft structures and engines to perform preflight inspection reducing human errors. Moreover it was recommended student pilots as well as maintenance crew confirm checklist together to enhance aviation safety.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.1
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• pp.53-61
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• 2021

This paper is a preliminary study for the development of a drone for inspection inside a boiler in a thermal power plant, which is a high-temperature environment, and validated whether the drone can fly normally through a high-temperature environment simulation using AirSim. In a high-temperature flight environment, the aerodynamic characteristics of the air density and viscosity are different from room temperature, and the flight performance of the drone is also changed accordingly. Therefore, in order to confirm the change of the aerodynamic characteristics of the propeller according to the temperature change, the propeller analysis and thrust test through JBLADE, and the operation characteristics prediction through the electric propulsion system performance prediction model were performed. In addition, the analysis and performance prediction results were applied to AirSim for simulation, and the aircraft redesigned through the analysis of the results. As a result of the redesign, it was confirmed that about 65% of the maximum power used before the redesign was reduced to 52% to obtain the necessary thrust when hovering in an environment of 80℃.