Development of a machine learning model for predicting abnormalities of commercial airplanes

Airplanes are a social necessity for movement of humans,goods,and other.They are generally safe modes of transportation;however,incidents and accidents occasionally occur.To prevent aviation accidents,it is necessary to develop a machine-learning model to detect and predict commercial flights using automatic dependent surveillance–broadcast data.This study combined data-quality detection,anomaly detection,and abnormality-classification-model development.The research methodology involved the following stages:problem statement,data selection and labeling,prediction-model development,deployment,and testing.The data labeling process was based on the rules framed by the international civil aviation organization for commercial,jet-engine flights and validated by expert commercial pilots.The results showed that the best prediction model,the quadratic-discriminant-analysis,was 93%accurate,indicating a“good fit”.Moreover,the model’s area-under-the-curve results for abnormal and normal detection were 0.97 and 0.96,respectively,thus confirming its“good fit”.

IMPROVED LANDING-GEAR DESIGN FOR FLEXIBLE AIRPLANE

Landing dynamic simulation and landing-gear optimization design are used to improve the landing-gear design for a flexible airplane. Landing response is simulated by using velocity-squared damping, polytropic exponential air-compression spring, tire force power function characteristics, and an equivalent three-mass system.Optimization of landing-gear parameters is performed considering the maximum displacement of the landing-gear shock stroke, the maximum landing-gear force and the maximum deformation of the wingtip in the landing impact. Resutls show that landing-gear design parameters have an important influence on the structural flexibility of the airplane. And the landing performance of the landing-gear can be improved by the optimized metering pin type landing-gear.

Impact of Ground Effect on Airplane Lateral Directional Stability during Take-Off and Landing

Computational simulations of aerodynamic characteristics of the Common Research Model (CRM), representing a typical transport airliner are conducted using CFD methods in close proximity to the ground. The obtained dependencies on bank angle for aerodynamic forces and moments are further used in stability and controllability analysis of the lateral-directional aircraft motion. Essential changes in the lateral-directional modes in close proximity to the ground have been identified. For example, with approach to the ground, the roll subsidence and spiral eigenvalues are merging creating the oscillatory Roll-Spiral mode with quite significant frequency. This transformation of the lateral-directional dynamics in piloted simulation may affect the aircraft responses to external crosswind, modify handling quality characteristics and improve realism of crosswind landing. The material of this paper was presented at the Seventh European Conference for Aeronautics and Space Sciences EUCASS-2017. Further work is carried out for evaluation of the ground effect aerodynamics for a high-lift configuration based on a hybrid geometry of DLR F11 and NASA GTM models with fully deployed flaps and slats. Some aspects of grid generation for a high lift configuration using structured blocking approach are discussed.

Effect of airplane transport of donor livers on post-liver transplantation survival

AIM To evaluate the effect of long haul airplane transport of donor livers on post-transplant outcomes. METHODS A retrospective cohort study of patients who received a liver transplantation was performed in Perth, Australia from 1992 to 2012. Donor and recipient characteristics information were extracted from Western Australian liver transplantation service database. Patients were followed up for a mean of six years. Patient and graft survival were evaluated and compared between patients who received a local donor liver and those who received an airplane transported donor liver. Predictors of survival were determined by univariate and multivariate analysis using cox regression.RESULTS One hundred and ninety-three patients received alocal donor liver and 93 patients received an airplane transported donor liver. Airplane transported livers had a significantly lower alanine transaminase(mean: 45 U/L vs 84 U/L, P = 0.035), higher donor risk index(mean: 1.88 vs 1.42, P < 0.001) and longer cold ischemic time(CIT)(mean: 10.1 h vs 6.4 h, P < 0.001). There was a weak correlation between CIT and transport distance(r2 = 0.29, P < 0.001). Mean follow up was six years and 93 patients had graft failure. Multivariate analysis found only airplane transport retained significance for graft loss(HR = 1.92, 95%CI: 1.16-3.17). One year graft survival was 0.88 for those with a local liver and was 0.71 for those with an airplane transported liver. One year graft loss was due to primary graft non-function or associated with preservation injury in 20.8% of recipients of an airplane transported liver compared with 4.6% in those with a local liver(P = 0.027). CONCLUSION Airplane transport of donor livers was independently associated with reduced graft survival following liver transplantation.

Compatible Design of the System to Detect Ships and Airplanes with a Ground Wave Over-the-horizon Radar

This paper provides a design method based on a time-shared form, which obtains the compatibility of signal and the system for detecting both ships and airplanes. Then, it gives the structure diagram of the system and the chart diagram of signal processing. Finally, the continuity problem of signal modulation for ship detection is discussed.

Analysis of Airplane Precipitation Operation on Embedded Convective Clouds in Hunan Province

Based on NCEP 1°×1° reanalysis data, ground encryption houdy precipitation, FY-2E stationary satellite and Doppler radar data, the structural characteristics of precipitation clouds in Hunan Province and the effects of airplane precipitation operation were analyzed. The results show that under the effects of low-pressure system and southwest monsoon, Hunan was rich in water vapor, which was beneficial to the maintaining of precipitation clouds. During the process of the artificial precipitation operation over Hunan Province, convection developed vigorously, and precipita- tion was strong in the south of the province; embedded convective clouds were dominant and precipitation was weak in the east of the province. Cloud optical thickness correlated with ground precipitation positively. After catalyzing, echo at high altitudes responded firstly, and the echo intensi- ty increased gradually; the response of low-altitude echo lagged behind that of high-altitude echo. It shows that catalysis could lead to increase of upper precipitation particles in size and quantity. As time goes on, upper precipitation particles descended to low altitudes, so that echo intensity in- creased at low altitudes. It is clearly seen that catalysis could lead to increase of echo intensity and prolong the lifetime of target clouds to improve the area of strong echo zone, showing obvious positive catalytic effect. At the same time, houdy average precipitation in the affected region tended to increase stably and was obviously more than that of the contrast region where hourly average precipitation reduced gradually with time. The changing trend of hourly average precipitation in the affected region correlated positively with the response of radar echo.

Cost Comparision of Airplane Parking Methods at Apron of Maptuto International Airport

Three known designs for parking, frontal, angled and parallel, were presented. Aircrafts at aprons can be parked either by towing equipment （push-back） or by its own power （serf-powered parking）. The costs of these two methods for Maputo International Airport were investigated. Based on airplane parking design theory, formulas to calculate the annual maintenance cost at aprons were proposed. Calculation results indicate that self-powered parking is preferable, justified by the fact that this airport has low traffic volume. The system of aircraft parking adopted by this airport saves significantly the cost for purchase and subsequent maintenance of push-back.

To Understand Why Airships Lost the Sky to Airplanes Take a Look at the Network on the Ground

Zeppelins and airplanes went into a commercial competition during the 1920s and 1930s. The Zeppelin was a very costly and high-scale technology which operated with a number of devices less than fingers a hand has. Airplanes, however, were cheap both in investment and operation and improved their cost-effectiveness rapidly during the times. Therefore, it was clear from an economic point of view to develop a fast growing net of commercial airports serving an even fast growing number of passengers. This was self-energizing. Zeppelins, however, focused on one, later two point-to-point services only, justified by a lack of capital and permanent economic losses.

Robust Speech Endpoint Detection in Airplane Cockpit Voice Background

A method of robust speech endpoint detection in airplane cockpit voice background is presented. Based on the analysis of background noise character, a complex Laplacian distribution model directly aiming at noisy speech is established. Then the likelihood ratio test based on binary hypothesis test is carried out. The decision criterion of conventional maximum a posterior incorporating the inter-frame correlation leads to two separate thresholds. Speech endpoint detection decision is finally made depend on the previous frame and the observed spectrum, and the speech endpoint is searched based on the decision. Compared with the typical algorithms, the proposed method operates robust in the airplane cockpit voice background.

Asia's Largest Airplane Workshop

The four-airplane repair workshop built and put into operation in May 1996 by the Beijing Airplane Maintenance Engineering Co. Ltd is the largest one in Asia at present. At the 1990s world advanced level, it marks the fact that the maintenance facilities and technology of China’s civil aviation have entered the world’s advanced rank.

An Inteduction to the NO.605 Airplane Institute

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Airworthiness engineering and practices of COMAC C919 airplane

This paper systematically summarizes the basic philosophy and principles of airworthiness that COMAC follows in the process of developing C919 large passenger aircraft.It carries out type certification along with the aircraft development process,and plans and implements compliance activities for airplane design features.Targeting the airworthiness requirements,COMAC has also established an airworthiness management system,including design assurance system and continuing airworthiness system,to ensure that aircraft are designed in accordance with airworthiness requirements,to show compliance with airworthiness requirements and to continuously ensure the airworthiness of airplane by dealing with continuing airworthiness events in service.

Aerodynamic Modeling and Parameter Estimation from QAR Data of an Airplane Approaching a High-altitude Airport

Aerodynamic modeling and parameter estimation from quick accesses recorder （QAR） data is an important technical way to analyze the effects of highland weather conditions upon aerodynamic characteristics of airplane. It is also an essential content of flight accident analysis. The related techniques are developed in the present paper, including the geometric method for angle of attack and sideslip angle estimation, the extended Kalman filter associated with modified Bryson-Frazier smoother （EKF-MBF） method for aerodynamic coefficient identification, the radial basis function （RBF） neural network method for aerodynamic mod- eling, and the Delta method for stability/control derivative estimation. As an application example, the QAR data of a civil air- plane approaching a high-altitude airport are processed and the aerodynamic coefficient and derivative estimates are obtained. The estimation results are reasonable, which shows that the developed techniques are feasible. The causes for the distribution of aerodynamic derivative estimates are analyzed. Accordingly, several measures to improve estimation accuracy are put forward.

Evaluating effective swath width and droplet distribution of aerial spraying systems on M-18B and Thrush 510G airplanes

Aerial spraying plays an important role in promoting agricultural production and protecting the biological environment due to its flexibility,high effectiveness,and large operational area per unit of time.In order to evaluate the performance parameters of the spraying systems on two fixed wing airplanes M-18B and Thrush 510G,the effective swath width and uniformity of droplet deposition under headwind flight were tested while the planes operated at the altitudes of 5 m and 4 m.The results showed that although wind velocities varied from 0.9 m/s to 4.6 m/s,and the directions of the atomizer switched upward and downward in eight flights,the effective swath widths were kept approximately at 27 m and 15 m for the M-18B and Thrush 510G,respectively,and the latter was more stable.In addition,through analyzing the coefficients of variation(CVs)of droplet distribution,it was found that the CVs of the M-18B were 39.57%,33.54%,47.95%,and 59.04% at wind velocities of 0.9,1.1,1.4 and 4.6 m/s,respectively,gradually enhancing with the increasing of wind speed;the CVs of Thrush 510G were 79.12%,46.19%,14.90%,and 48.69% at wind velocities of 1.3,2.3,3.0 and 3.4 m/s,respectively,which displayed the irregularity maybe due to change of instantaneous wind direction.Moreover,in terms of the CVs and features of droplet distribution uniformity for both airplanes in the spray swath,choosing smaller CV(20%-45%)as the standard of estimation,it was found that the Thrush 510G had a better uniform droplet distribution than the M-18B.The results provide a research foundation for promoting the development of aerial spraying in China.

Drop test and crash simulation of a civil airplane fuselage section

Crashworthiness of a civil airplane fuselage section was studied in this paper. Firstly, the failure criterion of a rivet was studied by test, showing that the ultimate tension and shear failure loads were obviously affected by the loading speed. The relations between the loading speed and the average ultimate shear, tension loads were expressed by two logarithmic functions, Then, a vertical drop test of a civil airplane fuselage section was conducted with an actual impact velocity of 6.85 m/s, meanwhile the deformation of cabin frame and the accelerations at typical locations were measured. The finite element model of a main fuselage structure was developed and validated by modal test, and the error between the calculated frequencies and the test ones of the first four modes were less than 5%. Numerical simulation of the drop test was performed by using the LS-DYNA code and the simulation results show a good agreement with that of drop test. Deforming mode of the analysis was the same as the drop test; the maximum average rigid acceleration in test was 8.8 l g while the calculated one was 9.17g, with an error of 4.1%; average maximum test deformation at four points on the front cabin floor was 420 mm, while the calculated one was 406 mm, with an error of 3.2%; the peak value of the calculated acceleration at a typical location was 14.72g, which is lower than the test result by 5.46%; the calculated rebound velocity result was greater than the test result 17.8% and energy absorption duration was longer than the test result by 5.73%.

Integrated optimization on aerodynamics-structure coupling and flight stability of a large airplane in preliminary design

The preliminary phase is significant during the whole design process of a large airplane because of its enormous potential in enhancing the overall performance. However, classical sequential designs can hardly adapt to modern airplanes, due to their repeated iterations, long periods, and massive computational burdens. Multidisciplinary analysis and optimization demonstrates the capability to tackle such complex design issues. In this paper, an integrated optimization method for the preliminary design of a large airplane is proposed, accounting for aerodynamics, structure, and stability. Aeroelastic responses are computed by a rapid three-dimensional flight load analysis method combining the high-order panel method and the structural elasticity correction. The flow field is determined by the viscous/inviscid iteration method, and the cruise stability is evaluated by the linear small-disturbance theory. Parametric optimization is carried out using genetic algorithm to seek the minimal weight of a simplified plate-beam wing structure in the cruise trim condition subject to aeroelastic, aerodynamic, and stability constraints, and the optimal wing geometry shape, front/rear spar positions, and structural sizes are obtained simultaneously. To reduce the computational burden of the static aeroelasticity analysis in the optimization process, the Kriging method is employed to predict aerodynamic influence coefficient matrices of different aerodynamic shapes. The multidisciplinary analyses guarantee computational accuracy and efficiency, and the integrated optimization considers the coupling effect sufficiently between different disciplines to improve the overall performance, avoiding the limitations of sequential approaches utilized currently.

Prior-guided GAN-based interactive airplane engine damage image augmentation method

Deep learning-based methods have achieved remarkable success in object detection,but this success requires the availability of a large number of training images.Collecting sufficient training images is difficult in detecting damages of airplane engines.Directly augmenting images by rotation,flipping,and random cropping cannot further improve the generalization ability of existing deep models.We propose an interactive augmentation method for airplane engine damage images using a prior-guided GAN to augment training images.Our method can generate many types of damages on arbitrary image regions according to the strokes of users.The proposed model consists of a prior network and a GAN.The Prior network generates a shape prior vector,which is used to encode the information of user strokes.The GAN takes the shape prior vector and random noise vectors to generate candidate damages.Final damages are pasted on the given positions of background images with an improved Poisson fusion.We compare the proposed method with traditional data augmentation methods by training airplane engine damage detectors with state-ofthe-art object detectors,namely,Mask R-CNN,SSD,and YOLO v5.Experimental results show that training with images generated by our proposed data augmentation method achieves a better detection performance than that by traditional data augmentation methods.

NUMERICAL SOLUHON TO THE PROBLEM ON DlFFUSION OF CATALYTIC AGENTS RELEASED FROM AN AIRPLANE

A solution to the problem on diffusion of catalytic agents released from an airplane is sought.The variation of falling velocities of agent particles with the altitudes is taken into account in the study of the problem.A comparison is also made between the calculated results obtained by using the finite-difference method and those by using the analytic method,the similarities and the differences between the two methods are revealed.

AIRPLANE INFORMATION

Air France Over the past few years. Air France has been committed to bringing its brand image up-to-date. Today, Air France unveils an important new stage, its revamped logo. To avoid additional costs, the change will be made gradually. Aircraft will be painted with the

A China-US story in an airplane

Departure On July 19,the five of us—a delegation to the United States to celebrate the 40 th anniversary of diplomatic ties between China and the US—flew from Houston to North Las Vegas,the American sister city of Weinan,Shaanxi province,our hometown.We had just attended the Fourth China-US Sister-City Conference.