ANALYSIS OF GENERAL AVIATION FIXED-WING AIRCRAFT ACCIDENTS INVOLVING INFLIGHT LOSS OF CONTROL USING A STATE-BASED APPROACH

Inflight loss of control (LOC-I) is a significant cause of General Aviation (GA) fixed-wing aircraft accidents. The United States National Transportation Safety Board’s database provides a rich source of accident data, but conventional analyses of the database yield limited insights to LOC-I. We investigate the causes of 5,726 LOC-I fixed‑wing GA aircraft accidents in the United States in 1999–2008 and 2009–2017 using a state-based modeling approach. The multi-year analysis helps discern changes in causation trends over the last two decades. Our analysis highlights LOC-I causes such as pilot actions and mechanical issues that were not discernible in previous research efforts. The logic rules in the state-based approach help infer missing information from the National Transportation Safety Board (NTSB) accident reports. We inferred that 4.84% (1999–2008) and 7.46% (2009–2017) of LOC-I accidents involved a preflight hazardous aircraft condition. We also inferred that 20.11% (1999–2008) and 19.59% (2009–2017) of LOC-I accidents happened because the aircraft hit an object or terrain. By removing redundant coding and identifying when codes are missing, the state-based approach potentially provides a more consistent way of coding accidents compared to the current coding system.

ANALYSIS OF WING SEPARATION AND MID-AIR BREAKUP IN LIGHT TRAINING AIRCRAFT

Despite increasing discussions concerning the recently published wing spar airworthiness directive (AD) that affects many training aircraft and several current ADs for wing struts, there remains limited objective literature on incidents of wing separation or mid-air breakup. This paper attempts to report and analyse instances of wing separation and mid-air breakup of light training aircraft. A careful review of the United States National Transportation Safety Board (NTSB) aircraft accident database revealed that wing separations were more likely occur as mid-air breakup in PA28s than 172s/182s (OR: 3.06, 95 % CI: 1.3682 to 6.8536, p = .008). Additionally, wing separations were less likely to occur as mid-air breakups in the strutted 172s/182s than 177s/210s that don’t have a wing strut (OR: 0.11, 95 % CI: 0.04 to 0.29, p = <.001). This implies that non-strutted wing designs may be more susceptability to mid-air breakup than the strutted design of similar aircraft.

EXPERIMENTAL RESEARCH OF PARTIAL REGULAR MICRORELIEFS FORMED ON ROTARY BODY FACE SURFACES

The basic regularities in the influence of processing parameters on the geometrical characteristics of the partially regular microreliefs, formed on the rotary body face surface, are established. Combinations of partially regular microreliefs are formed by using a contemporary CNC milling machine, and an advanced programing method, based on previously developed mathematical models. Full factorial experimental design is carried out, which consist of three factors, varied on three levels. Regression stochastic models in coded and natural form, which give the relations between the width of the grooves and the deforming force, feed rate and the pitch of the axial grooves, are derived as a result. Response surfaces and contour plots are built in order to facilitate the results analysis. Based on the dependencies of the derived regression stochastic models, it is found that the greatest impact on the width of the grooves has the magnitude of the deforming force,followed by the feed rate. Also, it is found that the axial pitch between adjacent toolpaths has the least impact on the width of the grooves. As a result of the full-factorial experiment, the average geometric parameters of the microrelief grooves were obtained on their basis. When used, these values will provide for the required value of the relative burnishing area of the surface with regular microreliefs, and, accordingly, the specified operational properties.

CLARITY AND PRONUNCIATION OF AB-INITIO AIR TRAFFIC CONTROLLER

The increasing number of aircraft flying around the world has led to the requirement for air traffic controllers to improve their communication skills to face high demand traffic in the future. The paper examines the communication errors in the pilot-controller communication of six ab-initio air traffic controllers during simulation training. More than three hours of conversation were collected and analyzed qualitatively using conversational analysis. The transcribed data yielded a total of 62 instances of communication errors. The data revealed that clarity and pronunciation of ab-initio controllers contributed to problematic communication and reduced the efficiency of the air traffic controllers in communicating. In contrast, pronunciation errors rarely diminished comprehension amongst the controllers and pilots who share a similar first language and are familiar with the use of English in a lingua franca setting. The study also describes other instances of communication errors in pilot-controller communication. The results indicate that ab-initio air traffic controllers need to be proficient in three main areas in pilot controller communication to improve their performance: aviation phraseology, aviation English, and aviation knowledge. The findings suggest that pilots and air traffic controllers should achieve level 4 (operational) in aviation language proficiency test, before proceeding to aviation training that requires them to be proficient in their language skills.

TECHNOLOGY FOR RESTORATION AND REPAIR OF AIRCRAFT ENGINE PARTS

Problems of increasing the service life of compressor blades of aircraft gas turbine engines using detonation spraying technology are considered. The simulation of the parameters of the velocity and temperature of the particles of the sprayed material in the barrel of the detonation unit and in the flooded space to the substrate was carried out, followed by the choice of the optimal technological parameters of the spraying process. The control system of the detonation unit has been modernized. An experiment was carried out on the deposition of the Al2O3 coatings on the samples of a substrate made of titanium alloy VT3-1. Based on the results of the experiment, technological recommendations were developed concerning both the parameters of the spraying process and the parameters of the preparation of the substrate surface before spraying. The equipment for brazing the blades of the guide vanes is described and a device for spraying coatings on the end surfaces of the compressor blades is proposed. Thus, a complex technology has been developed for restoring the end surfaces of titanium alloy compressor blades by deposition of Al2O3 coatings.

DISTRIBUTIONS OF AIR TRAFFIC CONTROL STUDENTS’ ATTITUDES TOWARDS WORKLOAD

Mental workload is a well-known concept with a long development history. It can be used to examine students’ attitudes at the end of the educational process and compare them in groups or separately. However, building a continuous workload profile across the range of task complexity increase is still an urgent issue. All four groups of methods used to define mental workload have such flaws for the workload profile construction process as significant time requirements, single value processing and post-processing of the received results. Only one of them can be used without modifications to construct the operator’s attitude chart (profile) regarding the workload range and it doesn’t operate with more reliable absolute values. To resolve this problem, a special workload assessment grid was developed, considering the advantages of a subjective group of methods and seven core characteristics. The reasoning for grid axes choice, threshold values, and question formulation were provided. Statistics were calculated for the full sample, different grades, and educational institutions. Comparison of the received responses with referential values, cross-comparison between institutions and different grades were performed. The results contribute to such important aspects of workload, as redlines, workload profiling, and operator’s comparison.

SITUATION OF EUROPEAN AIRLINES CAUSED BY COVID-19: RESTRICTIONS, GOVERNMENT SUBSIDIES AND FUTURE PROSPECTS

The COVID-19 pandemic has been an unprecedented crisis, severely affecting the economy and many sectors, including the airline industry. This paper reviews this situation to see how airlines have acted since the beginning of COVID-19. The airline industry is dependent on financial support and subsidies to cope with the massive drop in air travel due to the coronavirus. The support received by the major airlines has been examined. In addition, a comparison has been made of all the aviation restrictions that have been implemented by different European governments. Travellers from countries with a higher incidence of cases, or with a growing rate of cases, have the most restrictions on travel to other countries. Furthermore, the strategies and protocols being implemented by certain airlines following the lifting of some of the restrictions on passenger air traffic are analysed. This paper will provide an insight into how airlines are coping with this unfavourable environment, as well as some of the future prospects and strategies of the aviation sector.

INNOVATION AT AIRPORTS: A SYSTEMATIC LITERATURE REVIEW (2000–2019)

Airports operate in a highly-competitive and challenging environment. Therefore, in order to remain competitive, innovation is imperative for airports. This paper aims to conduct academic research into innovation at airports by reviewing studies published from 2000 to 2019 for presenting key findings. A systematic literature review was made based on scientific papers indexed in Scopus with the keywords innovation and airport in the title, abstract or keywords sections, consolidating the innovation focus, approach and degree discussed with respect to innovation areas and territorial focal points. Consequently, it was found that research on airport innovation is: (i) mainly focused on products/services, (ii) concerned with leveraging ICT (Informatıon Communication Technology), (iii) implemented ad-hoc without a consolidated strategic approach, and (iv) lacks the input of external innovation scholars and specialists.

UNMANNED AIR VEHICLE PATH PLANNING FOR MARITIME SURVEILLANCE USING CLUSTER-BASE METHOD

This paper discusses a method to determine the operation route for unmanned aerial vehicles for maritime surveillance. It is well known that there are several methods to make an aircraft path planning for ground related missions. On the other hand, path planning for maritime purposes is unnoticeable. The major problem of path planning for maritime is the abundant number of nodes which can make the route becomes quite long. Hence, reducing the number of nodes is necessary to rectify this problem. The main method is to separate the surveillance area into a smaller area of operation using clustering methods and then analyze the vulnerable area using the database to create an optimum flight path in each operation area. Although this paper specifically addresses a maritime-related mission, the path planning procedures can be applied to other missions as well. In this research, the input is given from satellite recorded data. Natuna Sea is chosen as the main discussion as the Natuna Sea currently is one of the most vulnerable regions in Indonesia for illegal fishing activity. The result shows that the aircraft path able to cover most of the vulnerable areas while optimizing the route distance.

AN ALTERNATIVE APPROACH TO INDUCED DRAG REDUCTION

Induced drag constitutes approximately 40% of the total drag of subsonic civil transport aircraft at cruise conditions. Various types of winglets and several non-planar concepts, such as the C-wing, the joined wings, and the box plane, have been proposed for its reduction. Here, a new approach to induced drag reduction in the form of a combination of an elliptical and an astroid hypocycloid lift distribution is put forward. Lift is mainly generated from high circulation in the center part of the wing and fades away along the semi-span towards the wing tip. Using lifting line theory, the analysis shows that for fixed lift and wingspan the combined lift distribution results in an induced drag reduction of 50% with respect to the elliptical distribution. Due to its wing planform the combined lift distribution leads to a 51.5% higher aspect ratio. If structural constraints are placed, then the higher aspect ratio may affect wing weight. Although any substantial increase of wing weight is not envisaged, further study of the matter is required. Zero-lift drag and lift-dependent drag due to skin friction and viscosity-related pressure remain unaffected. The proposed lift distribution is particularly useful in a blended wing-body design.