Flight Hours Research Articles

Cost dynamics of helicopter emergency services: A Hungarian example

ObjectivesHelicopter emergency medical services (HEMS) have been integral to healthcare systems in developed countries and are becoming more relevant in developing countries. There is extremely scarce information available regarding the typical cost structure and dynamics of HEMS operation; thus, the limitation of knowledge may limit the shapers of national healthcare policy and potential private operators in starting such a service. This study aims to present the cost dynamics of HEMS operation. MethodsA systematic literature review was performed on open-source studies to obtain appropriate data. International benchmarks were found; nevertheless, as Hungarian data did not emerge, a recent investment into HEMS service was analyzed based on publicly available data from the Hungarian Air Ambulance and affiliated companies. The resulting cost base was allocated per flight hour, and a scenario was established with Western European (German) wages and salaries to challenge the aforementioned international examples. ResultsThe average cost of operation is calculated at EUR 2488 per hour or EUR 41.5 per airborne minute based on average mission duration. This result is quite below the German example of ca. EUR 55.4 per airborne minute and even less than the US and Australian examples, but once the costing model was recalculated with German salaries, the result was extremely similar to the literature review. Nevertheless, comparable international figures need further research, as ownership structure, cost allocation method, and accounting regimes may dramatically impact the cost per airborne minute. ConclusionThe cost of EUR 2488 per flight hour is a good indicator for an hourly rate of operations; however, when deciding on establishing such a service, the model needs to be adjusted for comparable salaries and foreign exchange rates. Nevertheless, if the number of flight hours can be well estimated, the yearly funding needs can be accurately determined using it.

Assessment of Potential Commercial Success of Business Jets with Natural Laminar Flow

The present research investigates the potential application of the natural laminar flow wing technology to business jet market segments from light to long-range jets. A database of existing business jets was generated to determine the range extension as a potential driver of customer interest. A conceptual design of several configurations for each market segment was performed to investigate potential improvements in the aircraft flight range, operating costs, and price changes using the technology. An initial sizing module and a low-fidelity multidisciplinary design optimization were used to size all aircraft. Results demonstrated a 13–30% increase in the flight range depending on the aircraft concept. Long-range jets with natural laminar flow could not achieve significant range extension due to a combination of the design airspeed and maintenance costs. A rapid increase in acquisition prices for all aircraft suggested that super-midsize and large jets that combine relatively low empty weight and high range extension could be more favorable options compared to other segments, but a significant reduction of acquisition costs and an increase in operating flight hours are required to make the technology implementation successful.

Aircraft piston engine load distribution in steady state operating conditions

The article presents the results of analysis of operational parameters of piston engine CA 912 ULT which is a propulsion system of ultralight gyroplane Tercel produced by Aviation Artur Trendak. Research was conducted under normal operating conditions of the autogyro and data was collected from 15 independent tests including a total of 14 flight hours conducted during training flights. Engine and flight parameters were recorded at 9 Hz during each flight using on-board Fligh Data Recorded system. Collective results were presented to show the statistical analyses of the individual parameters by determining the mean values, standard deviations and histograms of the distribution of these parameters. The analyses included engine speed, charge pressure, air temperature, oil temperature and exhaust temperature. Histograms of operating points defined by both engine speed and manifold air pressure were also determined. Analyses were carried out to determine the contribution of steady-state and transient engine operation. It was also shown that the dynamics of engine work in real operating conditions is small. Detailed analyses were conducted for steady-state conditions. The value of the engine load index was determined and its statistical analyses were carried out. It was shown that the engine operating points are concentrated mainly in the range of idle and power above 50% of nominal power. The most frequent range is 50% to 80% of nominal power.

Stretching and Self-Myofascial Release in Helicopter Aircrew to Reduce Neck and Back Pain (Phase 1).

This prospective intervention study was designed to determine the efficacy of a standardized Preflight/Postflight Stretches (PPS) protocol to reduce subjective neck and back pain scores in helicopter aircrew. Aircrew transient back and neck pain is well documented, and there is currently no standardized preflight and postflight stretching protocol for Naval Aviation. Subjects were recruited from two carrier air wing MH-60R squadrons at Naval Air Station Jacksonville. These carrier air wing squadrons were selected to control for size (number of aircrew), age, and operational tempo (number of flight hours). Subjects consisted of both pilots and enlisted aircrew. One squadron was designated as the control group, although the second squadron served as the intervention group. Subjects from both groups filled out the questionnaire. Only the intervention group completed the PPS protocol immediately after completing the questionnaire and before departing the squadron spaces for the aircraft outside. Upon landing, the aircrew completed a postflight debrief. Only the intervention group completed the PPS protocol after debrief. Both the intervention and control groups once again completed the questionnaire. Questionnaires were matched by using a generated anonymous subject ID. The amounts of change and pain levels were then compared using the Mann-Whitney test and the Fisher's exact test, respectively. The Kolmogorov-Smirnov test found the data to be nonparametric. The preflight and postflight overall (P ≤ .001), cervical (P ≤ .001), thoracic (P = .006), and lumbar (P = .004) differences between the control and intervention groups were found to be statistically significant when using the Mann-Whitney test. Preflight and postflight pain differences in the sacral region and "other" section were not found to be statistically significant (sacral, P = .618; others, P = .182). When evaluating the worsening of the pain level, 50 (92%) of the control flights in which PPS was not performed reported worse pain, compared to 21 (61.8%) in the intervention group where PPS was performed. The Fisher's exact test found the association between performing PPS and the worsening in pain to be statistically significant (P = .001) in the overall, cervical, thoracic, and lumbar regions. Therefore, the hypothesis was accepted in regard to overall pain, as well as in the cervical, thoracic, and lumbar regions. Aircrew back and neck pain because of flying is well documented. However, there is no standardized stretching protocol for aircrew to perform immediately preflight or postflight in U.S. Naval Aviation. This study demonstrated that PPS, a simple 5- to 7-min stretching routine, gives aircrew structure and can reduce postflight cervical, thoracic, lumbar, and overall pain. This phase proved to be safe as no adverse events were reported. The prehabilitation aspect could reduce conventional medical intervention, costly pharmacological management of neck and back pain, and be applied to other aviation populations in military and civilian communities.

Brain structure variability study in pilots based on VBM.

The impact of occupations on brain structures has attracted considerable research interests in the last decade. The aim of this research is to find the effect of flight training on brain gray matter volume of pilots. The whole-brain structural magnetic resonance imaging (sMRI) data collected from 26 pilots and 24 controls was analyzed using Voxel-based morphological analysis method (VBM) combined with T1 data to quantitatively detect the local gray matter of brain tissue and calculate the gray matter volume. The result shows that the pilot group has larger gray matter volume in the lingual gyrus and fusiform gyrus compared to the control group (P<0.05). Furthermore, there is a positive correlation between the gray matter volume and the number of flight hours (r = 0.426, P = 0.048) after studying the average gray matter volume value of the agglomerate of participants whose flight hours are between 0 and 1000 hours. The lingual gyrus and fusiform gyrus are involved in high-level visual processing, memory, multisensory integration and perception. The study has indicated the flight training could enlarge gray matter volume in the lingual gyrus and fusiform gyrus. During flying, pilots need to observe the instrumentation in the cockpit and fully interpret the readings, which may lead to the results.

A risk assessment method of aircraft structure damage maintenance interval Indexed by: considering fatigue crack growth and detection rate

The accurate assessment of aircraft structure damage risk is the premise of establishing reasonable, economic and reliable maintenance intervals. While many studies have proposed damage risk assessment methods for aircraft structures, these methods lack the quantification of risk. This paper proposed a risk assessment method of aircraft structure damage maintenance interval considering fatigue crack growth rate and crack detection rate. The damage process of aircraft structure was simulated by Monte Carlo simulation to realize the quantitative assessment of aircraft structure damage risk and maintenance interval. Taking an aircraft fleet as an example, the damage risk of its wing structure was simulated and analyzed. The results show that if the risk is controlled within a reasonable range, the maintenance interval should be shortened to 16 flight hours. At the same time, through the analysis of the risk classification standard and the crack detection rate, the quantitative evaluation of the risk classification standard was realized.

Adapting Commercial Best Practices to U.S. Air Force Maintenance Scheduling

This paper presents how the Inspection Development Framework’s (IDF) novel maintenance scheduling technique increased aircraft utilization and availability in a sample of the United States Air Force’s (USAF) C-5M Super Galaxy fleet. The hypothesis tested was “Can we execute segmented maintenance requirements during ground time opportunities in order to optimize flying?” We applied IDF to decompose the C-5M’s five-day Home Station Check (HSC) inspection into smaller work packages that subordinate to operational requirements and maintenance resource availability. Ten HSCs at Dover and Travis Air Force Base (AFB) were modified using IDF and measured against a control group of traditional HSCs. While statistical significance was not achieved given the small sample size, anecdotal results demonstrate improvements in maintenance downtime, sortie count, and flight hours for the experimental group across the two bases. Specifically, the pathfinder’s observed results extrapolated to all HSCs at each base projected an additional 15 flying days per year at Dover AFB and 29 sorties per year at Travis AFB. These C-5M improvements serve as a proof-of-concept for the USAF adapting commercial best practices to address declining aircraft readiness. IDF’s more agile and dynamic scheduling techniques also enable easier adoption of Condition Based Maintenance through a more integrated approach to optimally schedule maintenance requirements.

Função pulmonar em pilotos de combate

The effects related to work at high altitudes and acceleration force overload can generate physiological compensation mechanisms and eventual short-, medium- and long-term changes in lung function. Therefore, this study aimed to describe the chronic changes in lung function in combat pilots of the Brazilian Air Force. The sample consisted of 19 combat pilots and 20 controls. For pulmonary function measurements, we observed an increase in the mean values of Forced Vital Capacity (FVC) and Forced Expiratory Volume in the First Second (FEV1), a decrease in lung volume, an increase in resistance and work of breathing, in the exposed group compared to the control, with significant modifications to Residual Volume (RV) by Total Lung Capacity (TLC) in liters (L) and percentage (%). Similar behavior when evaluated according to flight hours, with an increase proportional to the increase in exposure time. Discrete changes, such as those observed in this research, may reflect adaptations of the respiratory system, bringing a complementary view to changes in chronic conditions.

БЕЗПЕКА ПОЛЬОТІВ ВЕРТОЛЬОТІВ ТИПУ Мі-8 ТА ЇХ МОДИФІКАЦІЙ

The article is an overview and information. The presented statistical data on the safety of flights of Mi-8 helicopters for the period from 1996 to 2011, the number of incidents, flight hours and their distribution for 2015-2019 confirm the feasibility of switching to the operation of helicopters according to their technical condition. The risk of fatal injury changes from its maximum values at 1000-1200 hours of operation per incident and reaches its minimum values starting from 4000 hours of operation.The number of incidents associated with the main gearbox is less for the Mi-8T helicopter compared to the Mi-8MTV(AMT) helicopter. The number of operating hours per incident associated with the operation of the fire alarm system in the area of the engines and the main gearbox also testifies in favor of the Mi-8T helicopter. The probability of an incident occurring per 1 hour of flight for a Mi-8 helicopter is less than that of the aircraft presented in the corresponding chart

An Optimization of Airline Scheduling Systems Based on a New Airline Pilots’ Fatigue Assessment Algorithm

Flight safety reports from different sources indicate that the proportion of accidents caused by flight fatigue accounts for 6-11% of all types of flight accidents. Current regulations in the civil aviation industry across the world generally emphasize the length of working hours rather than the influences of circadian rhythm disorders. Based on an analysis of the flight mission data of 567 pilots in 2019, which highlighted the associations between circadian rhythm disorders and flight fatigue, we have proposed a new algorithm to reflect pilots’ fatigue status to include five main indicators: actual working hours, circadian rhythm disorders, work rhythm disorder, altitude flight hours and flight crew composition. The results assessed by the new algorithm reported that about 70% of the airline pilots studied were under the threat of a high risk of fatigue in 2019. Subsequently, this research suggests the use of two algorithms to optimize pilot scheduling systems, and findings show that the percentage of pilots with a high level of fatigue can be largely reduced.

An Overview of the State of the Art in Aircraft Prognostic and Health Management Strategies

Aircraft are complex engineering systems composed of many interconnected subsystems with possible uncertainties in their structure. They often function for a long number of flight hours under varying or harsh environments. Hence, prognostic and health management (PHM) of critical subsystems or components within the overall system is crucial for maintaining the safety and reliability of the aircraft. This article reviews the state of the art in aircraft failure prognostic. The main definitions and concepts are presented and discussed. In addition, a selected important failure in the representative aircraft components is outlined, and various categories of prognostic strategies are reviewed. Finally, some recommendations and directions for the most promising research to address the PHM problem in aircraft are outlined.

Modelling for determining the adaptive potential of air carriers as participants in the process of creating a tourist product

The study is devoted to the adaptation capacity management of enterprises in the service sector. To determine the adaptation capacity of the air carrier, as an actor with a significant impact on the global tourism market, a mathematical model was proposed, which is characterized by constant variables. The model is based on the criterion of optimality of the discounted financial result of the air carrier for the entire period of modeling with restrictions on financial capabilities, demand on air lines, including the tourism, the number of flights and flight hours of planes, as well as general balance restrictions. Keywords: service sector, model, air carrier, tourism, airline, air transport market.

Study Of Music Performance The Orches Group Pancaran Senja Melayu Village Batu Besar Nongsa Batam

The study of musical performances in this study focuses on the musical performance itself. Where music performance events are present through two important roles, namely musicians and audiences who are the center when the music performance takes place. The success of a musical performance is through a procession of intense rehearsals, ongoing performances, and evaluations after musical performances. This study is a qualitative analytic description of the Pancaran Senja Malay Orchestra music group at Kampung Melayu Batu Besar Nongsa Batam. The research methods are field observations, interviews, literature studies, and participant observers. The results of the research are; that the success of the Pancaran Senja Malay Orchestra music performance until now has gone through the stages of the rehearsal process, show flight hours, and performance evaluation for the progress of the Pancaran Senja Malay Orchestra. This procession was born through discussion and agreement among fellow musicians, so that the continuity and survival of the Pancaran Senja Malay Orchestra music group was established.

MOSAiC-ACA and AFLUX - Arctic airborne campaigns characterizing the exit area of MOSAiC

Two airborne field campaigns focusing on observations of Arctic mixed-phase clouds and boundary layer processes and their role with respect to Arctic amplification have been carried out in spring 2019 and late summer 2020 over the Fram Strait northwest of Svalbard. The latter campaign was closely connected to the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Comprehensive datasets of the cloudy Arctic atmosphere have been collected by operating remote sensing instruments, in-situ probes, instruments for the measurement of turbulent fluxes of energy and momentum, and dropsondes on board the AWI research aircraft Polar 5. In total, 24 flights with 111 flight hours have been performed over open ocean, the marginal sea ice zone, and sea ice. The datasets follow documented methods and quality assurance and are suited for studies on Arctic mixed-phase clouds and their transformation processes, for studies with a focus on Arctic boundary layer processes, and for satellite validation applications. All datasets are freely available via the world data center PANGAEA.

Sustainable air transportation through the operational use of a social cost index

Air transportation is responsible for more than 10% of transportation related greenhouse gas emissions in the U.S. As policymakers and engineers search for methods to reduce aviation fuel consumption and the associated negative externalities, a metric used by aircrew on the flight deck may hold the key. The cost index metric and associated ECON speeds inputted into the flight management system control the aircraft's flying speed and ultimately the fuel consumed, and emissions produced. This study assesses the use of this operational tool to further green air transport production in U.S. domestic operations. Data from four major airline Boeing 737 NG routes are analyzed to estimate the effect of each carrier's cost index and ECON speeds on fuel consumption and emissions. Then a social cost index, which incorporates environmental costs, is estimated and tested using a Boeing 737 NG simulator across identical routes to determine the changes in fuel consumption and emissions. On average, we find that for every one unit decrease in an airline's cost index they reduce their fuel consumption by 5.37 lbs. per hour. Further, the average impact of implementing a social cost index is estimated to save nearly 22 gallons of jet fuel and reduce CO2 emissions by 453 lbs. per flight hour. These fuel and emissions reductions are estimated to generate a penalty of 1 min and 43 s on average per flight hour. Overall, we find that airlines can substantially reduce fuel consumption and emissions with minimal impact to operations via implementation of a social cost index.

A Simulation of Optimal Model on Fractional Aircraft Ownership (FAO) Management

Compared to owning a private jet, Fractional Aircraft Ownership (FAO) concept is a cheaper alternative for very mobile business persons who want to travel in comfort. The aircraft is owned by a number of customers (referred to as “owners”) and the flight hours of its operation are shared based on each owner’s portion. In this research, we do the simulation of an FAO company with very large demands with 27 cities of destination, which are commonly visited by business people in Indonesia. We derive flight demands stochastically from the owners and create optimal flying schedules based on the demands. Using the calculation of fixed and variable costs, we can determine the optimal flight pairings that minimized the operational cost. Eventually, we can determine the number of aircraft needed to be owned by FAO so the business will profit.

Reliability Analysis of a Fault-Tolerant Integrated Modular Motor Drive for an Urban Air Mobility Aircraft Using Markov Chains

Electrified urban air mobility (UAM) aircraft requires catastrophic failure rates for their propulsion systems that are lower than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-9}$ </tex-math></inline-formula> failures per flight hour. Electric machines and drives have been identified as limiting propulsion subsystems with failure rates in the range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-5}$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-6}$ </tex-math></inline-formula> failures/h. Fault-tolerant (FT) machine drives offer a promising approach to improve reliability using existing technology. An FT integrated modular motor drive (IMMD) design is proposed for a quadrotor UAM application, and its estimated reliability is studied using Markov chain analysis. Quantitative examples show that raising the repair rate for the motor drive modules significantly reduces the IMMD’s catastrophic failure rate. However, the lower bound on its failure rate with high repair rates is determined by its single-point failure (SPF) rate (e.g., motor bearings), highlighting the importance of aggressively suppressing as many of the IMMD’s SPFs as possible. Markov chain analysis shows that SPF suppression can result in major reductions in the IMMD catastrophic failure rate by factors exceeding <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{3}$ </tex-math></inline-formula> as the SPF rate is driven toward its ideal limit value of zero.

Trends and Characteristics of Incidents in China Civil Aviation: 1994–2020

Safety is of great importance to the sustainable development of air transportation. Because aviation accidents rarely occur, the traditional indexes based on fatal accidents and fatality could not provide enough information for accident prevention and continuous safety improvement. This paper collected data on 6,357 incidents in China civil aviation from 1994 to 2020. Afterward, a whole picture was drawn to reflect the detailed safety situation by analyzing the characteristics and trend of incidents. From 1994 to 2008, the annual number of incidents in China civil aviation remained relatively stable. After 2008, the number of incidents exhibited an obvious growth trend, but the incidents per million flight hours remained stable. From the direct cause of incidents, operator and mechanic are no longer the leading causes. Presently, 63.4% of incidents are caused by environmental factors, showing an increasing trend. From the operation phase, most incidents occurred during the cruise phase (29.8%), followed by the approach phase (19.4%), and the take-off phase (16.0%). In addition, there have been many incidents that occurred during uncertain phase. From the typical incidents, bird strikes and lightning strikes account for 43.8% and 6.7% of the total incidents, respectively, showing an annually ascending trend. Engine shutdown accounts for 9.4% but the number exhibits a descending trend. As an important index of safety, the trend and characteristics of incidents can specifically reflect the safety situation of the aviation industry, and provide a reference for accident prevention and continuous safety improvement.

Analysis and remedies for factors responsible for time between overhaul: a case study of Do-228 aircraft starter generator

The starter generator is used for cranking the engine and to produce electricity for the aircraft system after a sustainable speed. A review of relevant literature reveals the time between the overhaul of the Do-228 aircraft starter generator but did not go in-depth to unravel the factors responsible. A survey research method is adopted to elicit information on the factors. Raosoft sample technique calculator: a software that primarily calculates or generates the sample size of a research or survey was used to obtain the minimum sample size from the study population with the nominal rolls of the technicians as the sampling frame. The questionnaire was vetted and validated by a professional focus group discussion team. The result shows that the factors responsible for the time between overhaul of the starter generator are Environmental Factors (10%), Mechanical Factors (20%), Poor Maintenance Factors (17%), Time Due (25%), Usage/Life Cycle (16%) and Aging (12%). 75% overhaul is unscheduled. It is recommended that the overhauling of the aircraft starter generators be done at 900 as against 1000 flight hour intervals to mitigate unscheduled maintenance.

Literature Review: Lower Back Pain in Military Rotary Wing Pilots

Lower back pain (LBP) is a major health care challenge affecting the military aircrew worldwide. Researchers conducted studies addressing this problem to provide insight into various aspects of the illness. A comprehensive literature review was carried out on peer-reviewed sources to identify evidence-based Research on lower back pain. The analysis has shown the causes of LBP, including long flight hours, full body vibrations, and personal risk factors such as genetic health status and psychological risks. Prevention measures include physical exercise, reducing flight hours, better mental health, and cockpit and equipment redesign. Treatment options for LBP are battlefield acupuncture and exercise therapy. Additionally, lower back pain negatively impacts the lives of military pilots.