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The desire to use additively manufactured (AM) parts to ensure the availability of military aircraft, and to build limited‐life unmanned aerial vehicles (drones), coupled with the United States Air Force (USAF) approach to the airworthiness certification of AM parts has focused attention on durability analysis/assessment, and hence on the growth of small cracks in AM parts. Previous studies have shown that laser powder fusion built (LPBF) Scalmalloy® has: i) A yield stress and an ultimate strength that are greater than that of AA2024‐T3 and comparable to that of AA7075‐T6; ii) A resistance to crack growth that is better than that of AA7075‐T6 and comparable to that of AA2024‐T3. However, since the ability to predict the durability of a part is essential for its airworthiness certification, the present paper illustrates how to perform a linear elastic fracture mechanics (LEFM)‐based durability assessment of Boeing Space, Intelligence and Weapon System (BSIWS) LPBF Scalmalloy®. The durability study includes specimens with both machined surfaces and surfaces left in the as‐built condition. As a result, it would appear that BISWS AM LPBF Scalmalloy® is an ideal candidate for building limited‐life AM replacement parts for fixed and rotary wing aircraft and drones. [ABSTRACT FROM AUTHOR]

Urban Air Mobility (UAM) aims to transform urban transportation through innovative applications of electric Vertical Take-Off and Landing (eVTOL) aircraft. This paper focuses on tilt-wing eVTOLs, which offer significant advantages in energy efficiency and operational versatility. However, their unique flight characteristics present challenges, particularly during emergency landings. To address this, we propose a novel control framework that utilizes control barrier functions (CBFs) to ensure safe landings within urban environments, characterized by numerous obstacles and varying conditions. By integrating trajectory generation, tracking, and attitude control under stringent safety constraints, our method prioritizes occupant safety while complying with FAA airworthiness standards. We illustrate the framework's effectiveness through simulations, demonstrating its ability to guide eVTOLs to safe touchdowns despite power loss or other emergencies. This study not only advances the understanding of emergency landing mechanisms for eVTOLs but also contributes to the broader field of urban air traffic management, offering a foundation for future research and practical implementations of UAM. The innovative combination of CBFs and global optimization techniques sets a new precedent for resilient aircraft control in complex urban scenarios, paving the way for the safe integration of eVTOLs into everyday urban life. [ABSTRACT FROM AUTHOR]

This study introduces a model for predicting airworthiness in terms of meteorology information within the viewpoint of not only formal regulations but also informal rules based on acquired indicators from flight training organization experience (AIs‐FTOE). The case study is carried out in the Hasan Polatkan Airport which is used by the Department of Flight Training of Eskişehir Technical University (ESTU‐P), which is also recognized as a flight training organization. Within the study, the constraints (derived from regulations and AIs‐FTOE) and the data set used in models are explained. Also, the models are introduced based on the gated recurrent unit (GRU) and long short‐term memory (LSTM) with the use of empirical mode decomposition (EMD) and variational mode decomposition (VMD). Finally, a model‐selective mechanism (MSM) is proposed to use the models in common. The findings show that the models presented in the study produce successful results that can be used in flight training organization's (FTO) planning studies. The MSM uses GRU and LSTM together with decomposition techniques to provide more advanced prediction capabilities. When the literature is examined, it is observed that although meteorological conditions are of vital importance in the efficiency of FTOs, there are not enough studies on airworthiness based on meteorology. So, a model that will assist in scheduling plans is presented for FTOs. Airworthiness analysis of forecasting can provide a comprehensive reference to support planning efficiency in FTOs. To the authors' knowledge, this study will be the first in the literature on airworthiness that presents the MSM using a hybrid deep learning algorithm and decomposition of time series models in concurrent. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrogen power is one of the important forms to promote the realization of the "double carbon" goal in aviation field. The manufacturing，testing and qualification of hydrogen power will provide important support for the realization of the "double carbon" goal in aviation field. In this paper，the development background of hydrogen energy power at home and abroad is analyzed in combination with the "double carbon" goal in aviation field，and the forward planning of hydrogen energy power and the latest progress of the overall flight test of hydrogen energy power are systematically reviewed. The key technologies of hydrogen power flight test are analyzed in detail，and the technology of adapting to aeroengine flight platform is analyzed emphatically. It covers hydrogen storage and transportation，adaptation transform of hydrogen powered flight platforms，special measurement technologies，safety protection and control technologies，flight test supporting facilities，flight test verification and evaluation technologies，and airworthiness compliance studies. The aim is to provide reference for the research on hydrogen power demonstration，hydrogen power product evaluation，safe operation of hydrogen power，aviation technology innovation，low carbon and high quality development of aviation.

Non-destructive testing (NDT) plays an important role in aircraft maintenance and repair processes, ensuring the structural integrity necessary for safe operation. The paper presents the design and evaluation of an animated, low-cost robotic NDT system tailored for inspecting composite bonding agents. The system integrates commercially available components, including a three-degree-of-freedom robotic arm and a Raspberry Pi 4B, managed by custom Python software with a user-friendly graphical interface. Mechanical Impedance Analysis (MIA) and Eddy Current Testing (ET) methods were employed to assess the system’s performance on representative test specimens. Results indicate that the system delivers reliable and accurate measurements comparable to commercial tools like the MAUS V, while offering simplicity and modularity. Limitations such as scanning speed and handling of complex geometries are acknowledged, with potential solutions proposed for future enhancement. The system provides an affordable and customizable alternative for NDT automation in the aerospace industry.

Certification of high-tech products, such as unmanned aircrafts, occupies a sufficient part of time and material resources for developers and manufacturers, which inevitably leads to the slowdown of production output. The article analyzes the methods of certification of unmanned aircrafts existing at the moment in some countries. It also reveals the existing difficulties in obtaining certification and passing tests to obtain it. In order to simplify the testing, the introduction of digital twin technology as a less resource-consuming procedure is proposed. This article can be useful both for developers and manufacturers, and certification centers.

Anomaly distribution is an essential input for the probabilistic damage tolerance assessment, which is required by the airworthiness certification criteria Federal Aviation Regulation (FAR) 33.70. The default anomaly distribution of hole features has been established and published in airworthiness advisory circular 33.70-2 based on historical anomaly data collected from cracked or ruptured parts recorded in laboratory analysis reports of the special industries before 2005. However, for other industries, this default anomaly distribution fails to reflect the machining level of these industries. Besides, insufficient historical maintenance anomaly data makes the mathematical model of the default distribution inapplicable, and few models can deal with the production data. Therefore, this paper proposes a model for achieving the anomaly distribution of hole features induced by machine or maintenance process, including collecting anomaly data, deriving the exceedance number by the probability of detection (POD), conducting the curve fitting process, and calibrating and modifying the anomaly distribution. The anomaly distribution and the probability of failure (POF) are dependent on defect numbers as well as confidence levels. To recommend the number of collected data and the correction factor for the POFs with different sample numbers and confidence levels, the sensitivity analysis is conducted by quantifying the influence of the anomaly distributions of different anomaly numbers on the POFs. Results show that when the anomaly number is 25, the differences between the POFs are less than 32.9%, and a 1.329 correction factor zP is supposed to modify the POF. When the anomaly number is larger than 50, a 1.2 correction factor zP is supposed to obtain the most conservative risk value with a 95% confidence level. [ABSTRACT FROM AUTHOR]

This paper aims to investigate phenomena that are related to SLD conditions in aircraft icing including gravity, non-spherical droplets, droplet breakup and droplet splash using an in-house computational tool. The in-house computational tool involves four modules for the computation of the flow field, droplet trajectories, convective heat transfer coefficients and ice growth rates. Droplet trajectories are computed using the Lagrangian approach, while ice growth rates are calculated using the Extended Messinger Model. In order to extend the capabilities of the computational tool to include SLD-related phenomena, empirical models that represent SLD physics are implemented. An extensive study has been performed using MS317 and NACA0012 airfoils, that aims to bring out the relative importance of the SLD-related phenomena, particularly on water catch rates and ice formation. The results of the study pointed to some important new conclusions that may shed further light on SLD physics. For example, multiple droplet breakup has been observed under certain conditions and droplet breakup emerged as a more important effect than previously reported. It was also seen that droplet splash influences both the energy balance and the mass balance in the icing process, which has been shown to have an important effect on the final ice shape, especially for very large droplets. [ABSTRACT FROM AUTHOR]

Despite children being vulnerable aircraft passengers, children's safety on aircraft does not attract enough public attention as it does in the automotive industry. Current regulations about Child Restraint Systems (CRSs) used on aircraft differ in various countries. This study introduces the potential injuries, injury mechanisms, and injury criteria for children on an aircraft. The protective effects of different CRSs are summarised. Among the four types of CRSs, automotive child seats are the most practical CRSs used on an aeroplane today. The airworthiness regulations and operation regulations of CRSs are also presented. The lack of injury criteria for the neck and abdomen in current regulations should be addressed. Finally, the social effects of mandatory regulations of using CRSs on an aircraft are discussed, and advice on the future improvement of children's safety in aircraft is provided. [ABSTRACT FROM AUTHOR]

The regulatory framework of Remotely Piloted Aircraft Systems (RPASs) has recently experienced an extraordinary evolution. This article seeks to improve the integration of certification considerations in RPAS conceptual design approaches so as to enhance the safety, certifiability and competitiveness of their resulting designs. The first part of the research conducts a two-stage analysis of contemporary regulations related to an RPAS's initial airworthiness. In the first stage, the broad international regulation paradigm is evaluated attending to a set of criteria that are tightly related to both airworthiness and design considerations. The second stage keeps the most promising documents from a design–integration standpoint, which are assessed according to their applicability considering both design and operational aspects. The results of this analysis provide insights regarding the main issues in airworthiness design criteria extraction and integration in design methodologies. To aid the designer in surmounting these challenges, a flexible procedure named DECEX is developed. Considering the documents and findings from the survey, and attending to the scope of the design methodology being developed, it aids in establishing a complete regulatory document corpus and in comparing and extracting the applicable airworthiness design criteria. Two case studies for different RPAS types are conducted to demonstrate its application. [ABSTRACT FROM AUTHOR]

Determining the criticality of ice shapes is a necessary condition for verifying compliance with icing airworthiness regulations. However, the clear, concise, and applicable criterion based on the geometric characteristics of ice shapes has not been clearly given out by current advisory circulars. To address this problem, this paper summarizes aerodynamic performance items and recommended ice shapes the latest version of CCAR-25 and corresponding advisory circulars for a variety of flight phases, including takeoff, holding, en route, DTO, etc., instead of the single phase of holding in the previous research. Based on the geometric classification of the ice shapes, the dominant parameters of various ice shapes are clarified by the correlation between the geometric parameters and aerodynamic effects. The geometric parameters to determine the criticality of specific ice shapes are defined as the roughness height and range for the roughness ice and the total projection height in the direction of lift for the horn ice. On this basis, the detailed determination criterion of critical ice shape geometries corresponding to different flight phases and aircraft components is formulated, which will provide an operational selection methodology for determining the geometries of critical ice shapes at the airworthiness certification stage. [ABSTRACT FROM AUTHOR]

The consequences of new airspace entrants, such as novel aircraft concepts with innovative propulsion systems, on air traffic management operations need to be carefully identified. This paper aims to assess the impact of future aircraft with different performance envelopes on the European air traffic network from a flow-based perspective. The underlying approach assumes that all certification-related questions concerning airworthiness have been resolved and do not take into account any economic factors related to airline operations. For example, for an innovative propulsion system, a short range all-electric aircraft is considered in this study. Aircraft trajectory calculations are based on the dataset of base of aircraft data (BADA), which are developed and maintained by EUROCONTROL. The new design concept is integrated into BADA as well, resulting in a new set of coefficients for the all-electric aircraft. In addition to the adjusted parameters which affect airborne performances, ground-related aspects are also taken into account. This includes assumptions on operational procedures, charging capacities and adaptions in infrastructure. Investigations are carried out at the trajectory level as well as at the airport and the entire network. [ABSTRACT FROM AUTHOR]

The safety of Jettisoned FDRS in the process of separation from an aircraft is a key factor in designing Jettisoned FDRs and enabling them to pass airworthiness certification and be widely used in civil aircraft. The separation process of Jettisoned FDR installed on NASA Common Research Model is studied by the simulation method based on anisotropic unstructured hybrid grid and overset grid technology coupled with the rigid body 6-DOF equation. First, the numerical simulation accuracy of software under same simulation method is verified by WPFS standard model. Then, according to the three main aerodynamic parameters, including incoming Mach number, angle of attack α and sideslip angle β, 10 conditions including standard condition are designed and the separation process of recorder is simulated numerically. The simulation obtained the movement of Jettisoned FDRs in 6 degrees of freedom relative to the body coordinate system in different operating conditions during the separation process and confirmed that Jettisoned FDRs can be safely separated under these operating conditions. Finally, combined with the standard operating condition, the impact of three parameters' changes on recorder's 6 degrees of freedom motion and the time required to complete separation are analyzed, and conditions to ensure the safe separation of Jettisoned FDRs are summarized according to the requirements of airworthiness terms. [ABSTRACT FROM AUTHOR]

This paper introduces the development history and process of low altitude economy, explains the characteristics and advantages of low altitude economy, and further discusses the development direction and trend of commercial low-altitude aircraft. By analyzing the current popular commercial aircraft avionics system design features and considering the current low-altitude economic application scenarios, the characteristics of commercial low-altitude aircraft avionics systems design are described. Then, through the analysis of the design of low-altitude aircraft avionics systems, this paper puts forward the additional airworthiness requirements of commercial aircraft avionics system designs in low-altitude operation environments and explains the problems that should be paid attention to in the low-altitude operation application scenario. Through the research application of the airworthiness requirements of commercial aircraft avionics system design in the low-altitude economy, this paper provides guidance for the future development of low-altitude aircraft avionics systems. [ABSTRACT FROM AUTHOR]

Hail absorption test of aeroengine is one of the important components of airworthiness certification. The accurate test data are closely related to the density and mechanical properties of the artificial hail used in airworthiness tests. Through experimental research, this study explores the impact of distilled water, carbonated water and deionized water on the density and mechanical properties of artificial hail. The study addresses the significant differences between the density and mechanical properties of artificial hail and natural hail in existing studies. Based on this, a new method for preparing airworthiness test hail is proposed. The results indicate that artificial hail samples with distilled water as the hail core and carbonated water as the hail shell have densities ranging from 0.87 cm3 to 0.89 cm3. Furthermore, the estimated average maximum compressive strength of samples is 6.538 MPa, with some samples as low as 3.681 MPa. The mechanical properties of this artificial hail are more similar to those of natural hail. This method can more realistically simulate natural hail environments and can be used for the fine design of airworthiness certification criteria. [ABSTRACT FROM AUTHOR]

Copyright of Ingenius, Revista Ciencia y Tecnología is the property of Universidad Politecnica Salesiana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Maintenance, Repair, and Overhaul (MRO) is a critical industry sector that ensures the optimal performance and safety of aircraft and marine systems through comprehensive servicing, inspection, and repair. This literature review explores the complexities and challenges of MRO management, emphasizing its significance in maintaining airworthiness, operational safety, and compliance with regulations. It examines various risk management techniques, including Failure Mode and Effect Analysis (FMEA) and its extensions, to address equipment failures and enhance maintenance strategies. The review highlights how proactive and systematic approaches, such as risk analysis and Pareto analysis, are used to identify key issues impacting production efficiency and safety. Additionally, it discusses the growing role of advanced organizational practices and interdisciplinary considerations in optimizing maintenance outcomes. The review concludes by introducing the concept of modeling and simulation as valuable tools for improving MRO processes. By leveraging these techniques, organizations can better predict and manage maintenance needs, optimize resource allocation, and enhance overall operational performance. [ABSTRACT FROM AUTHOR]

The accumulation of ice on aircraft surfaces is known to endanger flight safety, which has driven the study and development of various methods to prevent this issue. A frequent problem aircrafts suffer is the ice accumulation on wings when flying across clouds with supercooled droplets. The shape and size of the ice accretion depend essentially on the flying speed, air temperature, number and size of microdroplets present in the atmosphere, and the exposure time to ice formation conditions. The numerical analysis of ice accretion involves differential equations for the resolution of the air velocity field, the transport of droplets, and their icing and melting. In this work, numerical models implemented in ANSYS CFD and Fensap-Ice codes are validated against experimental results and then applied to compute the ice formation on an MS(1)-0313 airfoil, used in a SAAB 340 wings, an aircraft that suffered a lethal accident in the Argentine Patagonia on May 18th, 2011. The simulation parameters were chosen based on meteorological reports of that day and the type of clouds that were present at the time of the accident. The goal of this work is to apply Fensap-Ice to verify whether icing on the wings could have been the cause of the accident. The results of this study confirm that the hypothesis is highly probable.

Double–double (DD) laminates approach enables the design of mass‐minimized composite structures with number and orientation of plies tailored on the acting loads. Thus, the investigation of the crashworthiness capabilities is crucial in assessing the airworthiness of DD designed structures. In this work, two composite fuselage barrel configurations with conventional and DD designed frames have been compared to study their crashworthiness performance during an impact event. Numerical results highlight that configurations with DD optimized frames exhibit performance in terms of crashworthiness and passive safety for passengers comparable to the one with conventional designed frames while reducing the structure's total mass by up to 13%. [ABSTRACT FROM AUTHOR]

Purpose: To ensure the safety of aircraft fuel tanks, the FAA issued an airworthiness clause (25.981(b)) suggesting that the risk of combustion and explosion be reduced by installing a Flammability Reduction Means or an Ignition Mitigation Means. The airflow distribution method has a significant effect on the inerting performance. Therefore, this study aims to determine an optimum airflow distribution method of the inerting system. Design/methodology/approach: This paper establishes the calculation model of the oxygen concentration in the ullage of a multi-bay fuel tank, calculates the oxygen concentration in the ullage of an aircraft tank in single-flow and dual-flow modes under series and parallel ventilation methods and analyses the inerting performance of the tank under different airflow distribution methods. Findings: The results show that: (1) the bleed flow rate required to achieve whole process inerting of multi-bay fuel tank in dual-flow mode is lower than that in single-flow mode; (2) under the parallel ventilation method, the decrease of oxygen concentration and the uniformity of each bay are better than that in the series ventilation method; (3) dual-flow mode staged ventilation method can be used to achieve the whole process inerting of the tanks under the minimum engine bleed consumption. Originality/value: The novelty of this paper is to analyze and optimize the airflow distribution method of the inerting system under the whole flight envelope to minimize the engine bleed consumption. [ABSTRACT FROM AUTHOR]

With the significant expansion of civil aviation, particularly in the low-altitude economy, there is a significant gap between the escalating demand for airworthiness certification of novel aircraft designs, such as electric vertical take-off and landing (eVTOL) vehicles, and the inefficiency of the current safety assessment process. This gap is partially attributed to safety assessors' limited exposure to these innovative aircraft models in the safety assessment process, necessitating extensive efforts in identifying precedents and their handling strategies. Complicating matters further, pertinent case studies are scattered across diverse, unstandardized digital formats, obliging assessors to navigate voluminous electronic records while concurrently establishing links among fragmented information scattered across multiple files. This study introduces an advanced information integration methodology, comprising a multi-level path-based architecture and a self-updating algorithm. The proposed method not only furnishes safety assessors with pertinent knowledge featuring explicative interconnectedness automatically, but also dynamically enriches this knowledge corpus through operational usage. Additionally, we devise a suite of evaluative criteria to validate the capacity of our method in processing and consolidating relevant safety datasets. Experimental analyses affirm the efficacy of our proposed approach in streamlining and refreshing safety assessment data. The automation of the retrieval of analogous cases, which relieves the reliance on expert knowledge, enhances the efficiency of the overall safety appraisal procedure. Consequently, this research contributes a solution to enhancing the velocity and accuracy of aircraft certification processes. [ABSTRACT FROM AUTHOR]

In the stage of aircraft development and airworthiness verification, it is necessary to master the influence of lithium-ion battery (LIB) thermal runaway (TR) propagation. In this paper, the battery TR propagation behavior under different trigger positions and modes is studied experimentally, and the calculation and comparison are carried out from the parameters of real-time temperature, voltage, propagation speed, total energy released, and solid ejecta. When the two adjacent cells at the top corner, side, and center of the module are overheated, TR occurs at about 1000 s for the triggered cells, while the whole-overheating trigger mode takes a longer time. The latter's transmission speed is extremely fast, spreading 2.67 cells per second on average. The heat generated by the solid ejecta of the whole-overheating trigger mode is 82,437 J, which is more destructive. The voltage of the triggered cell fluctuates abnormally in a precursor manner when the internal active substances in the cell undergo a self-generated thermal reaction. This work can provide a reference for the safety and economical design of system installations and the correct setting of airworthiness verification Method of Compliance (MoC) experiments to verify whether the aircraft can bear and contain the adverse effects caused by LIB TR. [ABSTRACT FROM AUTHOR]

Featured Application: The paper demonstrates key structural characteristics of a novel aluminum alloy conceived for AM-based components in the aviation frame. The recent advances achieved in additive manufacturing (AM) technology demonstrate the potential to realize customized metal components, ensuring weight reduction opportunities. These benefits make AM attractive for high-cost aerospace applications, especially where high geometric complexity is required. In the context of an EU research scenario, the H2020 MANUELA (Additive Manufacturing Using Metal Pilot Line) project promotes the development of new technologies for design optimization by enabling the application of novel materials in AM. This paper illustrates recent advances in a new aluminum alloy (Al-HS1) with high strength emphasizing all of the characterization steps at the coupon level. This material has been employed in the re-engineering of a conventional hydraulic manifold using a powder bed fusion-laser beam (PBF-LB) process. Both the simulations and structural tests allowed for proving its compliance and technological maturity with industrial standards and applicable airworthiness requirements. [ABSTRACT FROM AUTHOR]

In order to scientifically sort out the differences in airworthiness management of military and civilian aircraft and improve the airworthiness safety of military and civilian aircraft, the input-process-output ( IPO) model in system engineering theory was innovatively applied, and airworthiness management was regarded as a management process in system engineering. A airworthiness management process IPO model based on system engineering theory was established. A differential analysis of military and civilian aircraft airworthiness management was conducted using the five elements of input, output, enable, control, and activity in the airworthiness management process IPO model. The similarity between military and civilian aircraft airworthiness management lies in the fact that both are comprehensive and full process control management aimed at ensuring the safety of aircraft engines. The differences lie in the level of management and enforcement in terms of security objectives, management institutions, standards/ regulatory systems, tailorability of standards/ regulations, deployment and division of labor, and regulatory methods. The specific differences between military aircraft airworthiness management and civil aircraft airworthiness management were analyzed, which provides reference opinions for the subsequent development of military and civil aircraft airworthiness management. [ABSTRACT FROM AUTHOR]

Purpose: The lightweight design of aircraft seats can significantly improve fuel efficiency and reduce greenhouse gas emissions. Metal additive manufacturing (MAM) can produce lightweight topology-optimized designs with improved performance, but limited build volume restricts the printing of large components. The purpose of this paper is to design a lightweight aircraft seat leg structure using topology optimization (TO) and MAM with build volume restrictions, while satisfying structural airworthiness certification requirements. Design/methodology/approach: TO was used to determine a lightweight conceptual design for the seat leg structure. The conceptual design was decomposed to meet the machine build volume, a detailed CAD assembly was designed and print orientation was selected for each component. Static and dynamic verification was performed, the design was updated to meet the structural requirements and a prototype was manufactured. Findings: The final topology-optimized seat leg structure was decomposed into three parts, yielding a 57% reduction in the number of parts compared to a reference design. In addition, the design achieved an 8.5% mass reduction while satisfying structural requirements for airworthiness certification. Originality/value: To the best of the authors' knowledge, this study is the first paper to design an aircraft seat leg structure manufactured with MAM using a rigorous TO approach. The resultant design reduces mass and part count compared to a reference design and is verified with respect to real-world aircraft certification requirements. [ABSTRACT FROM AUTHOR]

The European Union Aviation Safety Agency (EASA) continues to promulgate Safety Management Systems (SMS) across aviation organizations when it recently issued SMS requirements for EASA certificated Part 145 maintenance, repair and overhaul (MRO) organizations and Part 21 Design & Manufacturing (D&M) organizations. Currently, the FAA has no such rule in place for these U.S. based organizations, which may challenge those doing business in countries where EASA policies apply. Given that most of the United States' D&M and MRO population is made up of smaller organizations, it is likely a U.S. SMS regulation will require justification of the associated costs and benefits. This study explored the potential benefits SMS may provide these organizations by exploring the overall scope and nature of safety controls implemented through Airworthiness Directives (AD), which may help safety practitioners better understand how SMS in D&M organizations may reduce the number of AD related corrective actions. Researchers analyzed a sample of 189 ADs issued over a ten-year period and found that approximately 55% of the sampled ADs were the result of a new risk control, and approximately 45% were the result of a revised risk control. In these cases, the risk controls were not sufficient, and the AD action was necessary to ensure an acceptable level of safety. More effective risk controls have the potential to significantly reduce the number of ADs the industry must address. Every AD involves unplanned costs, often at multiple levels, and other variables that must be managed and implemented as part of the aircraft maintenance and manufacturing process. SMS may further improve the industry's safety performance by reducing the number of corrective actions and their associated costs. [ABSTRACT FROM AUTHOR]

Bird striking engines are most likely to cause aircraft damage and accidents in bird strike accidents. In order to study the bird strike airworthiness performance of the first stage compressor rotor of the engine, bird strike tests are conducted on the engine rotor under working conditions. The bird strike test, in which the bird weight, velocity and rotate speed of engine blades are 1 000 g, 195 m/s, 8 525 r/min respectively, is made in a vacuum space. Based on the explicit collision dynamics analysis software PAM-CRASH, a corresponding blade bird strike numerical calculation model is established, and the rationality of the calculation model in this paper is verified by comparing it with experimental results. Also, the ability of engine blades against bird strike in different situations is researched. The results indicate that big bird strike leads to a worse situation compared with medium bird flock and small bird lock. Large deformation appears at the tip of the blades due to the impact at the tip part, while impact at the root and middle of the blades will cause a large concentrated stress around the root of blades, and lead to the fracture of the blade.