Human-centric uncertainty remains one of the most persistent yet least quantified sources of risk in aviation maintenance. Although established safety frameworks such as SMS (safety management system), STAMP (Systems-Theoretic Accident Model and Processes), and FRAM (Functional Resonance Analysis Method) have advanced systemic oversight, they fall short in capturing the dynamic, context-dependent variability of human performance in real time. This study introduces the uncertainty quantification in aircraft maintenance (UQAM) framework – a novel, predictive safety tool designed to measure and manage operational uncertainty at the task level. The integrated uncertainty equation (IUE) is central to the model, a mathematical formulation that synthesises eight empirically derived uncertainty factors into a single, actionable score. Using a mixed-methods design, the research draws on thematic analysis of 49 semi-structured interviews with licensed maintenance engineers, followed by a 12-month field validation across four distinct maintenance tasks. Results demonstrate that the IUE effectively distinguishes between low, moderate and high-risk scenarios while remaining sensitive to procedural anomalies, diagnostic ambiguity and environmental complexity. Heatmap visualisations further enable supervisory teams to identify dominant uncertainty drivers and implement targeted interventions. UQAM enhances predictive governance, supports real-time decision-making and advances the evolution of next-generation safety systems in high-reliability aviation environments by embedding quantitative uncertainty metrics into existing safety architectures.

This article studies the rise and fall of commercial aviation in Iran, then known as Persia, between 1923 and 1932. Two airlines, the German Junkers Luftverkehr AG and Britain’s Imperial Airways, invested significant time and effort in developing air routes but eventually failed due to financial hardship and political intransigence. Exploring this erratic development, the article has two aims: first, to investigate the entangled history of two of the world’s oldest airlines and the challenges they navigated; and second, to assess the fraught relationship between state and business interests. The German and British airlines were rivals in Iran, but they became partly dependent on each other. Both airlines suffered from the global political dynamics of the interwar period while Junkers, in particular, also struggled financially. Meanwhile, the Iranian state had yet to decide whether to view the new technology with enthusiasm or concern. Its ambivalent and reluctant reaction had profound effects on the trajectories of Junkers and Imperial Airways. Assessing the capability of a nascent airline industry to develop viable business models outside of Europe, the article also serves as a case study revealing the headwinds airlines encountered in the earliest phase of commercial aviation.

Aviation employees operate in a dynamic, complex safety-critical system that is filled with uncertainty, requiring quick and correct expert decision-making. The purpose of this study is to investigate the decision-making indicators among aviation employees. Fifty-five technical engineers and air traffic controllers participated in this study by completing the Cambridge Gambling Task (CGT) at one of Iran’s airports. The CGT provides one of the most reliable and widely used decision-making assessment tasks and related indicators, including decision-making quality, risk-taking, delay aversion, deliberation time, risk adjustment and overall bet ratio. Higher risk adjustment, less deliberation time, and a lower delay aversion index resulted in better decision-making quality. Higher risk-taking does not necessarily mean lower self-control. No significant differences were observed between the studied groups, including between air traffic controllers (both Ground and Tower vs. RADAR and Approach) and between air traffic controllers and technical engineers in the CGT performance. The decision-making quality increased with age and work experience, which has important implications for training and selection processes.

The aviation industry’s efforts to reduce carbon emissions have driven the rapid development and scale-up of sustainable aviation fuels (SAFs). SAFs have the potential to significantly reduce CO2 lifecycle emissions by up to 80% in comparison to Jet A and other conventional fossil-derived jet fuels. For multiple logistical and practical reasons, it is preferable to ensure that SAFs are ‘essentially identical’ (also referred to as ‘drop-in SAF’) to conventional jet fuel in terms of their performance, durability and compatibility with existing hardware systems. Because the majority of SAFs are not identical (non-drop-in) to conventional jet fuel, they have not been approved for use in their neat (100%) form. Instead, these non-identical SAFs are named synthetic blend components (SBC) as they are blended with conventional fuels to different extents per ASTM D7566-23a. It should be noted that there are on-going efforts to develop non-drop in SAF specifications to broaden their proliferation and maximise the aviation industries’ ability to reduce CO2 lifecycle emissions. One very important area of focus is the compatibility of SAFs with engine and fuel system seals, specifically understanding the dynamics of elastomeric seals. To address this, a novel approach has been developed to measure seal dynamics in flowing fuel. This technique has been applied to study the dynamic seal behaviour of four industrially relevant elastomer seals commonly employed in aviation fuel systems. The study involved three test fuels: (i) conventional fossil-derived Jet A, neat hydroprocessed esters and fatty acids (HEFA) SAF, and neat alcohol to jet (ATJ) SAF. Notably, both HEFA and ATJ fuels contain 0% aromatics, in contrast to Jet A, which typically contains around 17% aromatics by volume. The novel fuel-elastomer test rig used in this study was designed to simulate a practical scenario in which fuel flows through the inner surface of a pre-loaded static O-ring. The results of these tests demonstrate that the behaviour of different nitrile elastomers is unique to their formulation, and in all cases, the behaviour in HEFA and ATJ SAF differs significantly from that in Jet A. However, new fuel approval tests may only list one type of elastomer for evaluation, for example the ‘Fit-for-Purpose’ test in ASTM D4054-22 Tier 2 lists one specific nitrile. The findings of this study highlight the complexities of fuel-elastomer interactions within nominally identical chemical families and emphasise the potential risks of assessing compatibility based on tests conducted with a single member of a chemical family.

Identifying the absence of situation awareness (SA) in air traffic controllers is critical since it directly affects their hazard perception. This study aims to introduce and validate a multimodal methodology employing electroencephalogram (EEG) and eye-tracking to investigate SA variation within specific air traffic control contexts. Data from 28 participants executing the experiment involving three different SA-probe tests illustrated the conceptual relationship between EEG and eye-tracking indicators and SA variations, using behavioural data as a proxy. The results indicated that both EEG and eye-tracking metrics correlated positively with the SA levels required, that is, the frequency spectrum in the β (13–30 Hz) and γ (30–50 Hz) bands, alongside the fixation/saccade-based indicators and pupil dilation increased in response to higher SA levels. This research has substantial implications for investigating SA using a human-centric approach via psychophysiological indicators, revealing the intrinsic interactions between the human capability envelope and SA, contributing to the development of a real-time monitoring system of SA variations for air transportation safety research.

Runway overruns (ROs) are the result of an aircraft rolling beyond the end of a runway, which is one of the accident’s types that most frequently occurs on aviation. The risk of an RO arises from the synergistic effect among its precursors, such as unstable approaches, long touchdowns and inadequate use of deceleration devices. To analyse this complex socio-technical system, the current work proposes a customised functional resonance analysis method, called FRAM-FDM, as traditional techniques of risk and safety assessment do not identify the interactions and couplings between the various functional aspects of the system itself, especially regarding human and organisational components. Basically, FRAM-FDM is the coupling of a traditional FRAM with flight data monitoring (FDM) techniques, used here to quantify the variabilities of the flight crew performance while executing the required activity (i.e. the landing). In this proposal, these variabilities (i.e. the FRAM functions aspects) are aggregated by the addend of a logistic regression, resulting in a model to evaluate the flare operations and the brake application profile effect on the remaining distance to the end of the runway, used as a reference to classify the landing as acceptable or not. The present application of the FRAM-FDM assesses the operational risk of a sample fleet in overrunning the runway during landing, highlighting the brake pedal application profile as the most relevant contributor. The model improves the knowledge about the system behaviour, being useful to direct flight crew training.

Aviation passenger screening has been used worldwide to mitigate the translocation risk of SARS-CoV-2. We present a model that evaluates factors in screening strategies used in air travel and assess their relative sensitivity and importance in identifying infectious passengers. We use adapted Monte Carlo simulations to produce hypothetical disease timelines for the Omicron variant of SARS-CoV-2 for travelling passengers. Screening strategy factors assessed include having one or two RT-PCR and/or antigen tests prior to departure and/or post-arrival, and quarantine length and compliance upon arrival. One or more post-arrival tests and high quarantine compliance were the most important factors in reducing pathogen translocation. Screening that combines quarantine and post-arrival testing can shorten the length of quarantine for travelers, and variability and mean testing sensitivity in post-arrival RT-PCR and antigen tests decrease and increase with the greater time between the first and second post-arrival test, respectively. This study provides insight into the role various screening strategy factors have in preventing the translocation of infectious diseases and a flexible framework adaptable to other existing or emerging diseases. Such findings may help in public health policy and decision-making in present and future evidence-based practices for passenger screening and pandemic preparedness.

This article investigates the role of foreign technical experts in developing China's aviation infrastructure from the 1980s to the present. Focusing on a series of training and technical aid programmes, it traces the influx of critical know-how from Europe, Japan and North America during the period of reform and opening up. Through fieldwork conducted at airports in Beijing, Hong Kong and Shanghai – and expert interviews with architects, planners and engineers – the article sheds light on the instrumental role played by foreign technical experts. By establishing a leading-edge set of airport planning practices, these aviation professionals accelerated the modernization of China's transport infrastructure and its reintegration into the world economy. Moreover, by positioning China as a global leader in infrastructure development, they laid the technical foundations for Chinese foreign policy endeavours that seek to export an infrastructure-led model of economic development to Africa, Asia and the former Soviet sphere.

Why do policy experimentation regimes breakdown? And, if there are recognizable patterns of experimental failure, what might explain the variation? Focusing on aviation, finance and food safety, this article considers why a policy style that has been credited with China's successes in the past is failing to address governance challenges in these sectors at present. The article moves beyond discussions of policy mis-implementation by reframing experimental failure as a case of policy maladaptation under conditions of complexity and ambiguity. Maladaptation describes how approaches used in previous periods to foster adaptation can inadvertently make a system less resilient in the future. The analysis shows how the degree of consolidation of previously successful experimental regimes lends itself to certain types of maladaptation in the present: consolidated regimes are unable to generate policy alternatives (aviation), moderately consolidated regimes are maladapted for selection (finance), and unconsolidated regimes impede niche creation (food safety).

Complex domestic airspace requires collision risk models and monitoring tools suitable for arbitrary aircraft trajectories. This paper presents a new mathematically based collision risk approach that extends the International Civil Aviation Organisation (ICAO) models to full aircraft encounters based on real trajectory data. A new continuous time intervention model is presented, along with a position uncertainty propagation model that better reflects aircraft behaviour and allows generalisation to all trajectories to eliminate degenerate cases. The proposed risk model is computationally efficient compared to the models it is based on and can be applied to large-scale trajectory data. The utility of the model is demonstrated through a series of case studies using real aircraft trajectories.