Runway Conditions Research Articles

DESIGN OF IMAGE PROCESSING APPLICATION FOR FOREIGN OBJECT INSPECTION USING DRONE ON AIRCRAFT RUNWAYS

Flight safety is a crucial aspect of the aviation industry, heavily reliant on optimal runway conditions for successful takeoffs and landings. Foreign Object Debris (FOD) such as stones and potholes on the runway pose significant threats, necessitating preventive measures to avoid operational failures and aircraft damage. This research focuses on designing an image processing application for drone usage to enhance runway inspections. The Research and Development (R&D) method is employed from application design to field testing. Image processing utilizes the You Only Look Once (YOLO) method for swift and accurate FOD detection, maximizing drone effectiveness in identifying risks. Findings indicate that object size and image capture distance significantly affect detection performance. This analysis provides a basis for model optimization through improved data augmentation techniques and parameter adjustments to address challenges in detecting objects of various sizes.

The Effect of Air Density and Density Altitude on Landing Distance for Fixed Wing Aircraft

Abstract This thesis is concerned with studying the factors that effect on landing distance for fixed wing span aircrafts. These factors are divided related to types and characteristics of aircrafts, pilot’s technique, runway surface conditions, weathering conditions, and other environmental factors. Among these factors that were analysed in details both Air Density and Density Altitude to determine the effect of each factor on landing distance for fixed wing span aircrafts, what is the impact’s percentage of factor? Also, to determine the extent impact of each on the other, and the factors that affect them.

Numerical and experimental investigations of diffusion-induced boundary layer separation on aero-engine nacelles

Aero-engine nacelles have to fulfill design requirements at both cruise and off-design conditions. Under engine windmilling conditions the ingested streamtube massflow is relatively low. A key off-design condition is take-off, which, in conjunction with an engine windmilling scenario, results in the stagnation point of the ingested streamtube being located significantly inside the intake. The combination of high angle of attack and low engine massflow rates leads to a strong flow acceleration and subsequent diffusion of the boundary layer on the upper quadrants of the external nacelle cowl, which can terminate with subsonic separation from the leading-edge. Under this condition, Reynolds number effects can play a dominant role on the separation onset and characteristics and 3D-annular wind tunnel tests cannot always achieve Reynolds’ number equivalent to full scale. A novel quasi-2D rig configuration representative of the aerodynamics of a full-size aero-engine nacelle under windmilling end of runway conditions examined in detail the characteristics of the boundary layer on the external cowl of a nacelle prior to diffusion-induced separation. Separation of the boundary layer was independently promoted through changes to represent different engine massflow rates and freestream Mach number on the rig to determine the limits of steady Reynolds Averaged Navier Stokes (RANS) methods to discern the onset of boundary layer separation. For the conditions and geometry investigated, the combined experimental and computational results showed that there was laminar to turbulent transition of the boundary layer ahead of the subsonic diffusion. The work showed that steady RANS can predict the onset of boundary layer separation with an uncertainty of approximately 10% on notional engine massflow rate and 0.05 on freestream Mach number relative to a nominal operating freestream Mach number of 0.25. This provides guidance for the industrial design and optimization of future windmilling-tolerant nacelles for large ultra-high bypass ratio turbofan engines.

Vibration analysis and control of aircraft landing systems using proposed neural controllers

Nowadays, landing gears used in aircraft are the basic systems that carry the weight of aircraft systems and provide them to move on the ground. During the landing of aircraft, big and sudden vibrations occur as soon as the wheels come into contact with the runway. This situation negatively affects human safety, comfort and also the life of the landing gear system. Therefore, it is important to keep this vibration at permissible levels. This paper presents an improved vibration control method that controls the amplitudes of vibrations of landing systems. This paper presents proposed vibration control method that controls the angular position variables of the landing gear mechanism to control the vibrations occurring during landing. For different runway conditions and 200 km/h landing speed, the angular joint variables of the landing gear mechanism links are controlled using standard controller and a proposed neural controller structure. The simulation results are shown that the proposed neural controllers have better performance at vibration control of landing systems during landing.

Significance assessment of the main risk factors of landing accidents based on the results of the survey of civil aviation pilots

To study the problem of rough landings and aircraft runway excursions, a 22-item questionnaire, related to the subject under consideration, was drawn up for pilots. The questionnaire mainly focused on aircraft veering off. The range of issues covered different aspects of the problem, including: pilots' perception and a comparative evaluation of various risk factors; personal experience of landings with prerequisites for a runway excursion; decision-making for the go-around procedure; attitude to the airline policy regarding the landing quality assessment; reliability of information reported to the crew about weather and runway conditions; quality of simulator training for flights in terms of crosswind and slippery runways; modern aircraft systems to prevent a runway excursion, etc. More than 50 civil aviation pilots of different age, experience, including aircraft captains and co-pilots were interviewed. The survey was conducted remotely and anonymously. The processing of the questionnaires included a detailed analysis of the answers to each question. If a question was not answered or if there was some reasonable doubt as to its correctness, the questionnaire was excluded from consideration. The results of questionnaire processing for the entire group and for individual categories (young/experienced, captains/co-pilots, turboprop/turbojet aircraft) were presented and analyzed in this paper.

Prediction of water film depth on grooved airport runway induced by intense rainfall and wind

The runway water film depth (WFD) and its drainage have direct impact on hydroplaning risk and, consequently, aircraft operational safety. Understanding its relationship with weather and runway conditions can help manage such risk due to WFD. Thus, this study develops an empirical formula to correlate runway risk area with its influencing factors using a dataset generated by a comprehensive rainfall-runoff dynamic model. The model incorporates a wind speed induced stress and is validated with physical experiment collected data. The simulation and observation showed good agreement, verifying the model's capability to reasonably well simulate the WFD distribution on intricate grooved surfaces at the millimetre level, with the consideration of wind effects. Then, this study performs 456 numerical experiments at the lateral prototype scale considering various rainfall intensity, wind speed, runway deterioration area, and groove depth. The impact of these factors on the peak WFD and the runway risk area is quantitatively analysed. The proposed empirical formula and developed dynamic model enables accurate assessment and prediction of the runway risk area under extreme weather conditions for better management of potential hydroplaning.

Introduction of Global Reporting Format: Summary of the First Winter Season in Poland

Over the years, Global Reporting Format (GRF) was the first major change in the approach to evaluate runway conditions. The greatest impulse for this new regulation were incidents and accidents related mainly to runway excursions that occurred because of unfavorable weather conditions, when not only aircraft and different airport facilities but also human health and lives suffered. To better understand these changes, their advantages and their disadvantages, as well as the challenges that arose, an expert survey was carried out with duty officers of Polish airports, who directly made an assessment of runway conditions. Beside strengths of the GRF approach, research results show its weaknesses and uncertainties, especially when using the Runway Condition Assessment Matrix. In addition, in the article are presented a brief GRF description together with comparison with the previous reporting system and a discussion about air accident statistics related to a runway excursion, as well as a description and discussion of one selected air incident that took place in Poland.

Shimmy analysis of light weight aircraft nose wheel landing gear

This paper presents mathematical modeling and analysis of shimmy oscillations for a light weight airplane single wheel nose landing gear. Shimmy is a self-excited oscillation which occurs usually on the nose wheel landing gear assembly during ground maneuvers which is governed by the dynamic characteristics of the landing gear and tires. Shimmy oscillation may lead to reduce the fatigue life of the landing gear and fuselage structure. So, the study of dynamic response and stability boundaries of landing gear plays crucial role while designing of airplanes. In earlier studies of vehicle shimmy only 3 degrees of freedom (DOF) considered such as torsional mode, lateral bending mode and tire lateral deformation. In this work along with above mentioned DOF, two more additional DOF introduced such as axial vibration of strut and tire in order to include the effect of vertical dynamics on shimmy model. Gyroscopic coupling effect also included in the model to study its influence on shimmy. Analysis carried out to determine critical velocity region for occurrence of shimmy and to investigate the effectiveness of ground unevenness on the landing gear system for two different runway conditions such as flat runway and random roughness runway. The results are more helpful to study significant interaction between the different parameters of landing gear and to represent stability boundaries.

Analysis of Runways Surface Conditions Using Pavement Condition Index Method (Case Study: I Gusti Ngurah Rai International Airports)

The growth of aircraft and passenger movements every year requires the runway pavement structure to go above and beyond to accept dynamic loads caused by each type of operating aircraft. As a result of the significant growth value, it often causes the runway pavement structure to fail prematurely. Early failure of the runway pavement structure can be detected through the distress on the asphalt surface of the runway's flexible pavement. In this study, an analysis was carried out on the surface runway at I Gusti Ngurah Rai International Airport to determine the value of the runway pavement condition due to the soaring movement of aircraft and passengers at I Gusti Ngurah Rai situation in Indonesia. To obtain the value of the runway pavement conditions at I Gusti Ngurah Rai International Airport, it was analyzed using the Pavement Condition Index (PCI) method by conducting a visual inspection of the runway at I Gusti Ngurah Rai International Airport, which is divided into 30 segments with an area of each segment is about 4000 m2. The result of the analysis using the Pavement Condition Index (PCI) method is obtained that the runway at I Gusti Ngurah Rai International Airport has an average PCI value of 86.83, which is included in the very good category, the runway at I Gusti Ngurah Rai International Airport is considered to have disintegration and loss of skid resistance, with the most dominant types of damage in the form of patching, jet blast erosion, and bleeding.

Assessment of Runway Surface Conditions by British Pendulum Testing under the Global Reporting Format Winter Conditions

Poor braking performance on runways during winter is one of the most significant factors causing runway excursions. The International Civil Aviation Organization (ICAO) proposed a standardized method, named the Global Reporting Format (GRF), to establish runway surface conditions based on human observers. The GRF includes the description of most winter conditions. This work aimed at reproducing the GRF winter conditions in the laboratory, and to monitor the effect of the surface conditions, both without surface treatment and with surface treatment using liquid runway de-icing products (RDP) in both de-icing and anti-icing modes, using the British Pendulum Tester (BPT). The reproduction of the GRF winter conditions was possible in the laboratory since the BPT results correlated well with the GRF ratings. The worst conditions retained snow on ice. Wet conditions obtained with water and RDPs (potassium formate KFO, potassium acetate KAC and hybrid glycol-KAC HYB) behave similarly, indicating that RDPs alone on a runway for prevention are not any more dangerous than just water. The range from wet to dry, equivalent to a British Pendulum Number (BPN) from ~40 to ~50, was considered as good conditions on the runway. All the RDPs tested in the study improved the BPN from untreated conditions. In most of the conditions, the RDPs improved the BPN to values in the range of favorable conditions. KFO and KAC reacted almost in the same way for each condition. However, the HYB was better in conditions with ice. The obtained results demonstrated that simulated laboratory winter conditions could be used to determine the efficiency of RDPs in both de-icing and anti-icing modes.

Method for determining of aircraft landing performance by the simulation modeling

The paper considers the method for determining of aircraft landing performance, the basic of which is landing roll depending on the type and tire inflation pressure, runway surface condition, aircraft weight, availability of brake parachutes. The given results are received by the simulation modeling of aircraft spatial movement on a landing mode. The model of aircraft dynamics includes modules of aircraft movement kinematic parameters calculation, engine thrust, landing gear ground reaction, retarding force in wheel brakes and brake parachutes. Adequacy and reliability of the designed model of aircraft movement is confirmed by comparison of values of movement kinematic parameters obtained as a result of simulation modeling, and the parameters received from a real flight of the maneuverable aircraft. The designed simulation model allows us to analyze change of aircraft movement kinematic parameters, defining its flight mode. By the results of the conducted study, it has been defined that halving of normal operational pressure in MLG wheels decreases aircraft landing roll by over forty per cent. Installation of КТ-163D wheels instead of КТ-251А reduces landing roll by approximately a factor of one and a half times, use of brake parachutes reduces aircraft landing roll almost twice at landing on an icy runway. The introduced method is recommended to be used while studying aircraft landing performance during its design or modernization. It is also suggested to integrate the designed method for determining landing performance as a part of on-board information and control system with the view of immediate aircraft landing performance determination in real-time operation in specific flight conditions.

A decision support system for safer airplane landings: Predicting runway conditions using XGBoost and explainable AI

The presence of snow and ice on runway surfaces reduces the available tire-pavement friction needed for retardation and directional control and causes potential economic and safety threats for the aviation industry during the winter seasons. To activate appropriate safety procedures, pilots need accurate and timely information on the actual runway surface conditions. In this study, XGBoost is used to create a combined runway assessment system, which includes a classification model to identify slippery conditions and a regression model to predict the level of slipperiness. The models are trained on weather data and runway reports. The runway surface conditions are represented by the tire-pavement friction coefficient, which is estimated from flight sensor data from landing aircrafts. The XGBoost models are combined with SHAP approximations to provide a reliable decision support system for airport operators, which can contribute to safer and more economic operations of airport runways. To evaluate the performance of the prediction models, they are compared to several state-of-the-art runway assessment methods. The XGBoost models identify slippery runway conditions with a ROC AUC of 0.95, predict the friction coefficient with a MAE of 0.0254, and outperforms all the previous methods. The results show the strong abilities of machine learning methods to model complex, physical phenomena with a good accuracy.

Multiphase-Based Optimal Slip Ratio Tracking Control of Aircraft Antiskid Braking System via Second-Order Sliding-Mode Approach

This article addresses a novel multiphase-based real-time optimal slip ratio tracking control problem of an aircraft antiskid braking system (ABS) based on the second-order sliding-mode approach. First, a comprehensive dynamic model of an aircraft ABS is established, in which the coupling mechanism of the longitudinal, the vertical, and the pitching dynamics of the aircraft are thoroughly considered. Second, for the aircraft ABS with high nonlinearity, since the measurements of aircraft velocity and acceleration cannot be transmitted to the aircraft ABS in time, the second-order sliding-mode differentiator (SMD) will be designed to estimate them simultaneously. Then, the optimal slip ratio signal, which formulates the maximum friction coefficient, will be updated based on the static friction coefficient model with real-time measured and estimated signals. Furthermore, a novel multiphase-based slip ratio regulation algorithm integrated with the second-order sliding-mode control strategy is proposed on the basis of runway characteristics to track the optimal slip ratio signal, which can not only stop the aircraft faster but prevent the mainwheel from final locking. Finally, the simulation results are presented to demonstrate that the aircraft antiskid braking algorithm proposed in this article can effectively prevent the mainwheel from locking under different runway conditions, and significantly improve the braking efficiency.

Analisis Kelayakan Panjang dan Tebal Perkerasan Runway Untuk Pesawat Jenis B737-900ER yang Beroperasi di Bandar Udara Banyuwangi

Runway is an airport facility which is very important for aircraft landing and taking off. The runway is a square area on the surface of the airport that is prepared for aircraft take off and landing, without a well-planned and managed runway, the aircraft will not be able to use the airport. In designing the runway, it is strictly regulated regarding the length, width, orientation (direction), configuration, slope / slope, and thickness of the runway pavement. This final project will analyze the feasibility of the runway length and the thickness of the pavement (runway) for the operational plan aircraft that will be used in the next 20 years. With ARFL corrections to the existing runway conditions, the current runway length is 2,500 meters. For the next 20 years traffic flow is forecasted using linear regression analysis from 2011 to 2037. From the forecasting results, it was found that the total aircraft movement was 19,138 movements (R1), so it was planned to use the B 737 900 ER aircraft because this aircraft had a passenger capacity of 220 seats. This aircraft is the reference for the planning of the runway dimensions. Some of the resulting planning analyzes include: the length of the planned runway is 2,498 meters long and 45 meters wide. Meanwhile, the pavement planning analysis resulted in a surface layer thickness of 4 inches, a base coarse layer of 13 inches, and a subbase thickness of 22 inches.

Global Reporting Format (GRF) Application Automation for Runway Surface Conditions in West Africa

This paper aims to design an automated Global Reporting Format’s (GRF) application in order to reduce time of manual application (on a runway) of the Global Reporting Format developed by International Civil Aviation Organization (ICAO). A method has been used to measure and generate Runway Condition Report (RCR) automatically. The developed computing model is an autonomous and automatic application implemented specially for West Africa (and can be extended to any rainy area). It uses Arduino materials and computing code developed by the authors. Results obtained show that using that method to retrieve the Runway Condition Report (RCR) is fast, so human presence on the runway is reduced. Even though the results obtained using this model are slightly different from those expected, the actual runway conditions are not too much affected.

ASSESSING THE IMPACT OF THE SLOPES ON RUNWAY DRAINAGE CAPACITY BASED ON WHEEL/PATH SURFACE ADHESION CONDITIONS

Aircraft braking distance is dependent on the friction between the main gear tires and runway pavement surface.Pavement texture, which is divided into macrotexture and micro-texture, has a noticeable effect upon friction, especially when the surface is wet. A risk analysis framework is developed to study the effects of longitudinal and transverse slopes on the aircraft braking distance in wet runway conditions and their influences on the probability of landing overrun accidents.This framework is operating under various water-film thicknesses, Maximum Landing Weights (MLW), and touchdown speed probability distributions for an acceptable range of longitudinal/transverse slopes and pavement texture depths.A simulator code is developed that initially computes the existing water-film thickness, as the result of intense precipitation,under aircraft main gear (depend on aircraft category) and then applies this variable as one of the main inputs to the aircraft braking distance computation. According to the obtained results, longitudinal gradient does not have a significant effect on the existing water depth on the surface although it affects the flow path length. Furthermore, 1% to 1.5% transverse slope causes rapid drainage of water from the runway surface and considerably decreases the probability of runway excursion accidents.

Modelling of Evenness of Runways as an Element of Sustainable Airport Maintenance

The elevation of airport runways is specified in the operations manuals and in globally accepted design guidelines. Airport runways are constantly exposed to various physical and weather factors. However, these factors can deteriorate the condition of the runway to the point where it becomes unusable. Monitoring and the continuous inspection of runway evenness is an important element of a sustainable airport maintenance system. An important element of a sustainable airport maintenance system is a runway evenness detection and modelling system. The investigation of the use of various available methods for modelling runway evenness was conducted based on measurements of the actual condition of the existing runway at Edvard Rusjan Airport in Maribor, Slovenia. During the measurements of the runway condition, our own measurement equipment was used, which ensures the geodetic accuracy of the measurements. The novelty of the article is a comparison between five different approaches to modelling runway evenness: approximation with regression plane, inverse distance weighted interpolation (IWD) with a weighting factor of 1, 2, and 10, and interpolation based on a triangulated irregular network (TIN)–linear and cubic. In the methodology section, the advantages and disadvantages of the mentioned methods were described. The selected models were evaluated by required processor time, by the file size resulting from the modelling, and by the values of the descriptive statistics of the model deviation at the average uniform slope. It was found that the modelling method using linear triangular irregular network interpolation provided the most useful results. The results of the conducted analysis can be easily used in any runway management models at airport thet allow for professionally based actions aimed at ensuring the safety and efficiency of runway operations, especially at smaller, regional airports.

A method for calculating and evaluating user costs in airport pavement management systems

An efficient airport pavement management system is essential to judge current runway conditions and predict future runway conditions and support decisions. However, one of the limitations is insufficient scope for analysis of the infrastructure environment, particularly regarding loss of revenue due to the need for total or partial closure of the runway in life-cycle cost analysis (LCCA) approaches. In this article, a method is presented for calculating indirect/user costs based on the net present value related to closed runway time in the cash flow variable. This method integrates passenger demand forecasts based on machine learning and the net operating revenue of an airport. Relying on a case study of Brasília International Airport, the consideration of a variable called the ‘equivalent operational susceptibility area’ improved understanding of the financial impacts on indirect/user costs and direct/owner costs. This variable enabled visualisation of the conditions for the financial feasibility of pavement intervention scenarios. The proposed method uses the required time of runway closure and the area to be maintained as balance weights between the direct and indirect costs of LCCA. Therefore, it is not reasonable to relegate indirect/user costs to estimated values or aircraft and passenger movement fees.

A MILESTONE TO ENHANCE RUNWAY SAFETY: THE NEW GLOBAL REPORTING FORMAT

Runway excursion continues to cause serious deaths and economic losses in aviation. 179 people died in the accidents occurring between 2010 and 2019. The direct cost of accidents in 2019 is estimated at over $4 billion. A new method known as Global Reporting Format (GRF) is introduced after studies carried out by the International Civil Aviation Organization (ICAO) to prevent aircraft accidents caused by runway excursion and to minimize risks associated with it. GRF is considered an important milestone to flight safety by ICAO. In this study, GRF is explained with all its components, and benefits and transition to the application process are discussed. As a result of the study, it is assessed that GRF is a positive contribution to flight safety in the process of take-off or landing by matching information about runway surface conditions obtained to the flight crews especially in adverse conditions.

MSD-Based NMPC Aircraft Anti-Skid Brake Control Method Considering Runway Variation

In this paper, a nonlinear model predictive control (NMPC) method based on mixed slip-deceleration (MSD) with runway identification is proposed to prevent the aircraft wheels from locking up and improve the braking performance under time-varied runway conditions. The MSD control algorithm reduces the dependence of control performance on slip rate estimation accuracy and retains a good slip rate control performance. The proposed NMPC control method guarantees optimal braking torque on each wheel by individually controlling the slip rate of each wheel near the optimal point. A nonlinear brake control model based on aircraft ground taxiing dynamics is derived. In this model, the tire-runway friction coefficient–slip rate model under different runway conditions and vertical force variation caused by brake are considered. A runway identification algorithm based on friction coefficient and friction coefficient slope is used to identify the real-time runway status, based on which the prediction model and optimization function of the proposed control scheme are modified. The wheel slip stable zone and the system maximum brake torque are regarded as time-domain constraints of the NMPC for safety considerations and physical limitations. The control objectives of the NMPC include longitudinal deceleration, braking performance, and preservation of crew comfort. The proposed MSD-based NMPC controller is verified by a tricycle-geared aircraft model using MATLAB/Simulink software. Simulation results of different control schemes on a specific mixed runway show good performances of the proposed control method. The proposed control method provides a new efficient solution for aircraft wheel braking on variable runway.