Flight Maintenance Research Articles

MUSCULOSKELETAL DISORDERS AFFECTING WORK PERFORMANCE AMONG GROUND-HANDLING PERSONNEL: A SYSTEMATIC LITERATURE REVIEW

Ground-handling personnel are critical for airline operations and ensuring safety during flights. Yet, these workers are at risk of developing MSDs due to highly physically demanding tasks. which can impact their health and work performance. This review examines common risk factors affecting MSDs and their impact on work performance, while also exploring prevention and management strategies for this occupational group. A total of 342 articles were identified through an explorative search of the PubMed database, Direct Scopus, and Google scholar with the limitation of the year from to 2015-2024. Only 16 articles were considered and classified based on their operation category, such as ramp operation, flight maintenance, cabin crew and baggage handler articles. The results reveal that musculoskeletal disorders (MSDs) in ground handling personnel can be influenced not only by physical factors but also by organizational, psychological, and social aspects, which can negatively impact work efficiency and performance. ground handling workers are exposed to various musculoskeletal risks, including physical exertion, unnatural postures, Standing for extended periods., repetitive tasks, tight deadlines, and heavy lifting, as well as organizational and psychological concerns. It is crucial to mitigate these risks to safeguard and enhance musculoskeletal health of the workers.

Damage Analysis of Propeller Blade P/N R815505 with Root Cause Failure Analysis Method on ATR 72 Aircraft

The propeller blade is a component that is the main source of thrust on the ATR 72 aircraft. Based on data from the Aircraft Flight Maintenance Log (AFML) for the period 2019 – 2021 ATR 72 aircraft, the propeller blade component was damaged causing the need for unscheduled removal which had impact losses to airlines such as delays and aircraft-on-ground (AOG). This study aims to find the root causes of damage to the propeller blade components. Analysis was carried out using the Root-Cause Failure Analysis (RCFA) method using fault tree analysis (FTA) and fishbone diagrams as tools so that factors related to propeller blade damage will be found. The results of analysis using fault tree analysis (FTA) and fishbone found that the root cause of damage to the propeller blade was in the area of ​​the heating element (de-icer) as the top event, while the propeller blade operation, propeller blade maintenance and the ATR 72 aircraft operating environment were the intermediate events

A simulation framework for airline line maintenance crew sizes

The airlines are constantly challenged with the crew, fuel, and new regulation issues that impact their financial and operational performances. Some of these challenges are beyond the control of airlines. However, it is extremely important to be efficient in the areas that the airlines have control over. Flight line maintenance, also called as through flight maintenance, involves regular walk-around checks of aircraft between their arrival and successive departure at the airport. The lack of adequate line maintenance personnel has a major impact on on-time flight departures. Accordingly, having the right number of maintenance crew sizes is crucial for on-time performance and profitability in particular at their hubs and busy airports. This study offers a generic discrete-event simulation modelling for airlines to help them with staffing their line maintenance crew teams. The application of the model is presented to a US airline operating at their busiest hub. Different crew teams and their impact on key performance indicators are tested and reported for this airline.

Ral function in muscle is required for flight maintenance in Drosophila

ABSTRACTRal is a small GTPase of the Ras superfamily that is important for a number of cellular functions. Recently, we found that expression of Ral is regulated by store-operated calcium entry (SOCE) in Drosophila neurons. In this study, through genetic and behavioural experiments, we show that Ral function is required in differentiated muscles for flight. Reducing Ral function in muscles, specifically reduced duration of flight bouts but not other motor functions, like climbing. Interestingly, unlike in the nervous system, Ral expression in the muscle is not regulated by SOCE. Moreover, either knockdown or genetic inhibition of SOCE in muscles does not affect flight. These findings demonstrate that a multiplicity of signalling mechanisms very likely regulate Ral expression in different tissues.

Optimisation of military aircraft engine maintenance subject to engine part shortages using asynchronous metamodel-assisted particle swarm optimisation and Monte-Carlo simulations

ABSTRACTComprising the coordination of various maintenance levels, flight maintenance planning (FMP) constitutes an appealing and hard-to-solve optimisation problem. In this article, a modified version of the typical FMP problem is studied for a typical-size military fleet, focusing on engine maintenance: a disruption of the depot level maintenance (DLM) facilities is considered, causing long-term shortage of serviceable engine parts. In this context, an optimisation strategy is proposed to schedule engine and part exploitation so that engine availability be retained until the recovery of the DLM supply lines, and flight and maintenance requirements be fulfilled to the maximum possible extent. To incorporate the effects of stochastic events, model their interaction with the capacity of the available maintenance resources and assess the outcome of the proposed plans, Monte-Carlo simulations are employed. A computationally efficient variant of the asynchronous particle swarm optimisation method is introduced to find the optimal solutions, combining parallelisation of the evaluation calls with a metamodel-based pre-evaluation strategy to reduce the optimisation turnaround time. Tested on a full-scale application, the proposed method is shown to be capable of producing robust FMP solutions and, also, quantifying the maintenance chain's operating status to aid in long-term planning.

Maturation of a central brain flight circuit in Drosophila requires Fz2/Ca²⁺ signaling.

The final identity of a differentiated neuron is determined by multiple signaling events, including activity dependent calcium transients. Non-canonical Frizzled2 (Fz2) signaling generates calcium transients that determine neuronal polarity, neuronal migration, and synapse assembly in the developing vertebrate brain. Here, we demonstrate a requirement for Fz2/Ca(2+) signaling in determining the final differentiated state of a set of central brain dopaminergic neurons in Drosophila, referred to as the protocerebral anterior medial (PAM) cluster. Knockdown or inhibition of Fz2/Ca(2+) signaling during maturation of the flight circuit in pupae reduces Tyrosine Hydroxylase (TH) expression in the PAM neurons and affects maintenance of flight. Thus, we demonstrate that Fz2/Ca(2+) transients during development serve as a pre-requisite for normal adult behavior. Our results support a neural mechanism where PAM neuron send projections to the α' and β' lobes of a higher brain centre, the mushroom body, and function in dopaminergic re-inforcement of flight.

Airport Runway FOD Detection from LFMCW Radar and Image Data

Airport runway Foreign Object Debris (FOD) jeopardizes flight safety and leads to a large amount of financial cost on flight maintenance constantly. Several FOD detection systems based on a variety of detection techniques and architectures have been developed. This paper gives a brief introduction of our FOD detection system, in comparison with FOD detection systems currently in the international market. What distinguish our system from all the others is that, our detection approach is based on both linear frequency modulated continuous wave (LFMCW) radar signal and image data. This innovation combines the advantages of radar in shape detection and image in appearance detection. As a result, it increases the FOD detection rate and reduces the false alarming rate. Experiments following Federal Aviation Administration (FAA) advisory indicate that our system has reached the FAA requirements.

Neural responses from the wind-sensitive interneuron population in four cockroach species

The wind-sensitive insect cercal sensory system is involved in important behaviors including predator detection and initiating terrestrial escape responses as well as flight maintenance. However, not all insects possessing a cercal system exhibit these behaviors. In cockroaches, wind evokes strong terrestrial escape responses in Periplaneta americana and Blattella germanica, but only weak escape responses in Blaberus craniifer and no escape responses in Gromphadorhina portentosa. Both P. americana and B. craniifer possesses pink flight muscles correlated with flight ability while B. germanica possesses white flight muscles that cannot support flight and G. portentosa lacks wings. These different behavioral combinations could correlate with differences in sensory processing of wind information by the cercal system. In this study, we focused on the wind-sensitive interneurons (WSIs) since they provide input to the premotor/motor neurons that influence terrestrial escape and flight behavior. Using extracellular recordings, we characterized the responses from the WSI population by generating stimulus–response (S–R) curves and examining spike firing rates. Using cluster analysis, we also examined the activity of individual units (four per species, though not necessarily homologous) comprising the population response in each species. Our main results were: (1) all four species possessed ascending WSIs in the abdominal connectives; (2) wind elicited the weakest WSI responses (lowest spike counts and spike rates) in G. portentosa; (3) wind elicited WSI responses in B. craniifer that were greater than P. americana or B. germanica; (4) the activity of four individual units comprising the WSI population response in each species was similar across species.

Functional Complementation of Drosophila itpr Mutants by Rat Itpr1

: The Drosophila inositol 1,4,5-trisphosphate receptor (IP3R) and mammalian type-1 IP3Rs have 57–60% sequence similarity and share major domain homology with each other. Mutants in the single Drosophila IP3R gene, itpr, and Itpr1 knockout mice both exhibit lethality and defects in motor coordination. Here the authors show that the rat type-1 IP3R, which is the major neuronal isoform, when expressed in the pan-neuronal domain in Drosophila, functionally complements Drosophila IP3R function at cellular and systemic levels. It rescues the established neuronal phenotypes of itpr mutants in Drosophila, including wing posture, flight, electrophysiological correlates of flight maintenance, and intracellular calcium dynamics. This is the first in vivo demonstration of functional homology between a mammalian and fly IP3R. This study also paves the way for cellular and molecular analyses of the spinocerebellar ataxias in Drosophila, since SCA15/16 is known to be caused by heterozygosity of human ITPR1.

Encoding of stimulus velocity by insect cercal system wind-sensitive interneurons: A comparative study.

Encoding of stimulus velocity by insect cercal system wind-sensitive interneurons: A comparative study.

Wind Erosion Prevention and Repair of Composite Material Components of Civil Aircraft

This paper addresses how to discover wind erosion of aircraft components in time and to take appropriate measures to repair and prevent damage, thereby reducing the cost of aircraft maintenance and prolonging aircraft service life. The authors of this paper have extensively compiled and studied civilian aircraft maintenance data in the recent years from Guangzhou Aircraft Maintenance Engineering Co. Ltd. In this paper they discuss the aircraft components most susceptible to wind erosion, as well as repair methods and prevention mechanisms. These findings can serve as a reference and a guide to civilian aircraft flight maintenance, repair, and routine inspections.

Octopaminergic modulation of temporal frequency coding in an identified optic flow-processing interneuron.

Flying generates predictably different patterns of optic flow compared with other locomotor states. A sensorimotor system tuned to rapid responses and a high bandwidth of optic flow would help the animal to avoid wasting energy through imprecise motor action. However, neural processing that covers a higher input bandwidth itself comes at higher energetic costs which would be a poor investment when the animal was not flying. How does the blowfly adjust the dynamic range of its optic flow-processing neurons to the locomotor state? Octopamine (OA) is a biogenic amine central to the initiation and maintenance of flight in insects. We used an OA agonist chlordimeform (CDM) to simulate the widespread OA release during flight and recorded the effects on the temporal frequency coding of the H2 cell. This cell is a visual interneuron known to be involved in flight stabilization reflexes. The application of CDM resulted in (i) an increase in the cell's spontaneous activity, expanding the inhibitory signaling range (ii) an initial response gain to moving gratings (20–60 ms post-stimulus) that depended on the temporal frequency of the grating and (iii) a reduction in the rate and magnitude of motion adaptation that was also temporal frequency-dependent. To our knowledge, this is the first demonstration that the application of a neuromodulator can induce velocity-dependent alterations in the gain of a wide-field optic flow-processing neuron. The observed changes in the cell's response properties resulted in a 33% increase of the cell's information rate when encoding random changes in temporal frequency of the stimulus. The increased signaling range and more rapid, longer lasting responses employed more spikes to encode each bit, and so consumed a greater amount of energy. It appears that for the fly investing more energy in sensory processing during flight is more efficient than wasting energy on under-performing motor control.

Flight Initiation and Maintenance Deficits in Flies with Genetically Altered Biogenic Amine Levels

Insect flight is one of the fastest, most intense and most energy-demanding motor behaviors. It is modulated on multiple levels by the biogenic amine octopamine. Within the CNS, octopamine acts directly on the flight central pattern generator, and it affects motivational states. In the periphery, octopamine sensitizes sensory receptors, alters muscle contraction kinetics, and enhances flight muscle glycolysis. This study addresses the roles for octopamine and its precursor tyramine in flight behavior by genetic and pharmacological manipulation in Drosophila. Octopamine is not the natural signal for flight initiation because flies lacking octopamine [tyramine-beta-hydroxylase (TbetaH) null mutants] can fly. However, they show profound differences with respect to flight initiation and flight maintenance compared with wild-type controls. The morphology, kinematics, and development of the flight machinery are not impaired in TbetaH mutants because wing-beat frequencies and amplitudes, flight muscle structure, and overall dendritic structure of flight motoneurons are unaffected in TbetaH mutants. Accordingly, the flight behavior phenotypes can be rescued acutely in adult flies. Flight deficits are rescued by substituting octopamine but also by blocking the receptors for tyramine, which is enriched in TbetaH mutants. Conversely, ablating all neurons containing octopamine or tyramine phenocopies TbetaH mutants. Therefore, both octopamine and tyramine systems are simultaneously involved in regulating flight initiation and maintenance. Different sets of rescue experiments indicate different sites of action for both amines. These findings are consistent with a complex system of multiple amines orchestrating the control of motor behaviors on multiple levels rather than single amines eliciting single behaviors.

Most of NASA budget boost going to international space station

NASA will focus on expanding support for a permanent human presence in space while maintaining level science funding for previously planned projects, said NASA Administrator Michael Griffin at a 5 February briefing regarding the agency's Fiscal Year (FY) 2008 budget request.The proposed FY2008 budget allots $17.3 billion for NASA, an increase of 3.1% over the proposed budget for FY2007. Much of the additional funds would go to exploration capabilities and space operations—which would get an 11% increase in funding for a total of approximately $6.8 billion—primarily for shuttle missions to continue assembly of the International Space Station (ISS) and for station and flight maintenance.

Real-time accommodation of actuator faults on a reusable rocket engine

An intelligent control system for reusable rocket engines is under development at the NASA Lewis Research Center. The primary objective is to extend the useful life of a reusable rocket propulsion system while minimizing flight maintenance and maximizing engine life and performance through improved control and monitoring algorithms and additional sensing and actuation. The main result of this work is the successful integration and real-time demonstration of model-based fault detection with a reconfigurable control as a new technique for valve fault accommodation on a reusable rocket engine. The focus here is on detecting and accommodating a frozen (stuck in a fixed position) oxidizer valve during a down-thrust and up-thrust manoeuvre by examining fault parameters produced by the algorithm. The detection scheme estimates the position of the frozen valve as a function of the fault parameters. Real-time simulation results demonstrate the effectiveness of the approach for two fault scenarios during a typical throttling manoeuvre.

Level of operator control and changes in heart rate variability during simulated flight maintenance.

The demands of dynamic monitoring and fault diagnosis for flight engineer trainees were examined in relation to changes in heart rate (HR) and two spectral analysis measures (midfrequency: 0.07-0.14 Hz; high frequency: 0.15-0.40 Hz) of heart rate variability (HRV). Eleven trainee flight engineers were studied, as part of their training and assessment, over three 3-h sessions in a cockpit simulator. During each session, faults and incidents programmed into the system had to be detected, diagnosed, and corrected. Electrocardiograms were taken, and each session was recorded on videotape. Work phases were classified from video analysis of flight maintenance activities, using Rasmussen's cognitive control taxonomy, into monitoring, routine (rule-based), and problem-solving (knowledge-based) phases. HR and HRV were found to be sensitive to different phases of the work environment. HRV was suppressed during the mentally demanding problem-solving mode of the level flight phase, but only for the midfrequency component. Elevated heart rate, in contrast, was associated with the more generally stressful takeoff and landing phases. The findings support both the use of HRV as a physiological index of mental effort and its value in operational contexts, and the value of ecologically derived methods of evaluating differences in work demands in complex systems.

Ontogenetic studies of flight initiation in Locusta: Wind response of an identified interneurone (TCG)

The tritocerebral commissure giant (TCG) wind-sensitive interneurone is involved in initiation and maintenance of flight in adult locusts. In this paper we study this interneurone in the imago and non-flying larval instars. Cobalt fills show that the TCG establishes its adult morphology by the first larval instar. An accompanying axon, apparently representing the peculiar tritocerebral commissure “dwarf” (TCD) is present, too, at least for the last preimaginal instars. Physiological tests show similar responses of the TCG to wind stimuli in the 4th, 5th instar and adult stages. Spike activity, however, is usually higher in adult compared to larval instars. It is possible that all interneurones, involved in adult-specific motor patterns (such as flight), are present in preimaginal stages and can be activated independently of the function of the final motor system.

Heliothis virescens: Response characteristics of receptor neurons in Sensilla Trichodea type 1 and type 2

Partial electroantennograms (EAGs) and single cell recordings fromHeliothis virescens males have demonstrated the presence of pheromones receptor neurons in sensilla trichodea type 2 as well as in type 1. This is supported by cobalt tracing experiments, showing that primary axons from the distal flagellum, containing only s. trichodea type 2, project into the macrogiomerulus complex in the male antennal lobes. Four types of finely tuned pheromone receptor neurons were found in males, whereas in females the corresponding neurons responded mainly to host odors. In males the majority (75 and 18%, respectively) were tuned to the majorHeliothis virescens pheromone components (Z)-11-hexadecenal (Z11-16∶A1) and (Z)-9-tetradecenal (Z9-14∶A1). The others (5 and 2%, respectively) responded specifically to (Z)-1 1-hexadecen-1-ol (Z1 1-16∶OH) and (Z)-1 1-hexadecen-1-ol acetate (Z1 1-16∶Ac). No neurons responding selectively to the minor pheromone components were found. The Z11-16∶A1 neurons of both sensilla types possessed similar specificity. However, the sensitivity decreased toward the medial and distal part of the flagellum, where s. trichodea type 2 are located. This suggests that the pheromone concentrations can be detected peripherally by a spatial as well as a temporal mechanism. Differences in temporal response patterns (pronounced phasic vs. tonic component) were found within the same type of neurons, suggesting different ability to encode intermittency of the pheromone plume as well as to mediate maintenance of flight.

Flight Thresholds of the Armyworm (Lepidoptera: Noctuidae)

Flight initiation threshold temperatures for agitated and undisturbed adult armyworms, Pseudaletia unipuncta, were measured. A predefined sequence of disturbances was applied to individual moths in an empty environmental chamber at various constant temperatures. With this agitation, the minimum flight threshold observed was 4°C, and the majority of moths could initiate flight at 10°C or above. A linear trend was noted between the log of duration of preflight wing shivering and ambient temperature. There were no detectable interactions with the sex or age of moths. Undisturbed moths were placed on oat seedlings at various constant temperatures under the photoperiodic conditions of rearing and left overnight. The presence of wing scales on a surface coated with Tanglefoot indicated flight. Flight was indicated at a minimum of 8°C. Flight maintenance thresholds were determined by lowering the temperature in a small tubular enclosure containing a single flying moth. Thresholds averaged 5.0°C for females and 3.9°C for males, with a minimum observed threshold of −l°C. No significant interactions with moth age or relative humidity at testing were noted.

Flight-initiating interneurons in the locust.

We have used intracellular recording and staining techniques to investigate the cellular mechanisms for the initiation and maintenance of flight in the locust, Locusta migratoria. In particular, we examined the properties of a small group of interneurons in the mesothoracic ganglion. We refer to these interneurons as 404 neurons. Their structure has been described, in a closely related species, by Watson and Burrows (21). Using a preparation in which intracellular recordings could be made from the main neurite of a 404 neuron during the generation of flight activity, we observed that the 404 neurons discharged tonically throughout flight episodes elicited by a constant wind stimulus on the head and by a sudden dimming of the lights. Their discharge rate was linearly related to the frequency of the flight activity. Depolarization of individual 404 neurons often initiated flight activity in quiescent preparations, and the application of hyperpolarizing currents during a flight episode either slowed or stopped flight activity. Hyperpolarizing currents also prevented the initiation of flight activity in some preparations. Individual 404 neurons were not always necessary for the generation of flight activity, since flight activity sometimes persisted when all spiking in a 404 neuron was prevented by the application of a hyperpolarizing current. We conclude that the 404 neurons function to initiate and maintain flight activity in response to wind stimulation of the head, but we have not yet established that they are the only thoracic neurons with this function. The 404 neurons discharged with a high-frequency burst at the time of triggering of a kick. Since the motor program for a jump is similar to that for a kick, the 404 neurons may also be involved in linking the initiation of flight activity to the jump. None of our data indicate that the 404 neurons receive input from the central rhythm generator. Thus the neuronal circuitry for flight appears to be hierarchically organized with at least one distinct neuronal system providing a tonic drive to initiate and maintain activity in the system that patterns activity in flight motoneurons.