Browse Topic: Airworthiness
In response to the current airworthiness regulations’ inability to cover the stall flight test requirements under icing conditions of civil aircraft with high-angle-of-attack restriction function and the lack of relevant flight test technologies in China, a study was conducted on the differences in airworthiness provisions for stall characteristics under icing conditions of such aircraft. Key technologies, including simulated ice accretion stall flight test methods, ice installation strategies, and data analysis techniques, are proposed and successfully applied to a specific civil aircraft. The results demonstrate that the methodologies proposed in this paper can effectively support simulated ice accretion stall tests, providing valuable insights for other similar aircraft.
Rolling-element bearings in rotorcraft dynamic systems are critical components susceptible to rolling contact fatigue (RCF), a dominant degradation mechanism manifesting through subsurface-initiated spalling, surface micropitting, and fatigue fractures. Robust inspection strategies compliant with EASA and FAA requirements are therefore essential. Traditional methods are often invasive, requiring disassembly, and are susceptible to human-factor errors. Smart Duplex introduces a design-for-monitoring architecture integrating in-situ videoscopic and coherence scanning interferometry (CSI) for high-resolution 3D surface mapping, including under partial grease coverage. This paper details a repeatability and reproducibility (R&R) framework ensuring metric consistency; a maintainability assessment projecting significant man-hour reductions and high availability; certification rationale emphasizing airworthiness improvements via enhanced detectability, workload reduction, and digitized inspection records; and an airworthiness mapping supporting threat assessments, Airworthiness Limitations Section (ALS) entries, and usage-based maintenance credits. By embedding sensing capability and digitizing inspection records, Smart Duplex minimizes downtime, mitigates human-factor errors, and facilitates predictive maintenance, optimizing cost, enhancing performance, and ultimately improving safety.
This paper details comprehensive analysis modeling and analysis supporting the development of the Research Aircraft for eVTOL Enabling techNologies (RAVEN). An isolated rotor model was developed in CAMRAD II, and predictions of rotor performance and rotor aeroelastic stability were generated. The rotor stability predictions are part of assessing airworthiness of the RAVEN vehicle. The performance predictions were used to calibrate the surrogate model for the NASA Design of Rotorcraft (NDARC).
Civil and military rotorcraft operators desire enhanced capabilities from their vehicles in terms of mission efficiency, effectiveness, productivity, and availability. A critical element of this challenge is associated with providing cold weather availability. Currently, cold weather operations are enabled by regulatory actions leading to Limited Approvals, Qualifications, Clearances, and Restrictions. Cold weather certification (clearance of a new aircraft) and continuing airworthiness (maintaining effectiveness of fielded aircraft) are data driven processes. This work provides guidance on an Icing Encounters Survey (IES) based data gathering method supporting continuing airworthiness organizations in improving fleet safety and capabilities during cold weather operations.
Airworthiness certification of aircraft requires an Airworthiness Security Process (AWSP) to ensure safe operation under potential unauthorized interactions, particularly in the context of growing cyber threats. Regulatory authorities mandate the consideration of Intentional Unauthorized Electronic Interactions (IUEI) in the development of aircraft, airborne software, and equipment. As the industry increasingly adopts Model-Based Systems Engineering (MBSE) to accelerate development, we aim to enhance this effort by focusing on security scope definitions – a critical step within the AWSP for security risk assessment that establishes the boundaries and extent of security measures. However, our findings indicate that, despite the increasing use of model-based tools in development, these security scope definitions often remain either document-based or, when modeled, are presented at overly abstract levels, both of which limit their utility. Furthermore, we found that these definitions frequently lack alignment with airworthiness security regulations. To address these two distinct gaps, this paper presents a model-based approach for detailed security scope definitions using the Systems Modelling Language (SysML). Our approach aligns with airworthiness security regulations ED-202A / DO-326A and ED-203A / DO-356A and incorporates a SysML profile based on the CORAS language for accurate modeling of security scopes. This facilitates a model-based security risk assessment by creating unambiguously system models that represent assets through model elements, document entry points to the assets and determine their environment. This SysML-based approach supports certification related activities by ensuring that security scope definitions are comprehensive and aligned with airworthiness regulations, directly addressing the identified gaps. The approach's applicability and effectiveness are demonstrated through an illustrative example in the domain of aircraft cabin system development. Moreover, the approach provides valuable inputs that assist operators in deriving guidance for the safe operation and maintenance of the aircraft, complementing existing methods and practices.
Airworthiness Considerations for Human Engineering in Acquisition.
Aerospace is an industry where competition is high and the need to ensure safety and security while managing costs is foremost. Stakeholders, who gain the most by working together, do not necessarily trust each other. Changing backbone technologies that drive enterprise systems and secure historical records does not happen quickly (if at all). At best, businesses adapt incrementally, building customized applications on top of legacy systems. The complexity of these legacy systems leads to duplication of efforts and data storage, making them very inefficient. Technology that augments, rather than replaces, is needed to transform these complex systems into efficient, digital processes. Blockchain technology offers collaborative opportunities for solving some of the data problems that have long challenged the aerospace industry. The industry has been slow to adopt the technology even though experts agree that it has real potential to revolutionize the global supply chain—including maintenance, repair, and overhaul (MRO)—driving tremendous cost, excess inventory, and inefficiencies out of the system. This chapter discusses how the adoption of blockchain technology could have a significant impact on the aerospace industry and addresses some of the unsettled concerns surrounding the implementation of the technology.
The extent of automation and autonomy used in general aviation (GA) has been steadily increasing for decades, with the pace of development accelerating recently. This has huge potential benefits for safety given that it is estimated that 75% of the accidents in personal and on-demand GA are due to pilot error. However, an approach to certifying autonomous systems that relies on reversionary modes limits their potential to improve safety. Placing a human pilot in a situation where they are suddenly tasked with flying an airplane in a failed situation, often without sufficient situational awareness, is overly demanding. This consideration, coupled with advancing technology that may not align with a deterministic certification paradigm, creates an opportunity for new approaches to certifying autonomous and highly automated aircraft systems. The new paths must account for the multifaceted aviation approach to risk management which has interlocking requirements for airworthiness and operations (including training and airspace integration). They occur across a variety of different operational paradigms with varying roles for the human and the systems in question. If implemented properly, autonomy can take GA safety to the next level while simultaneously increasing the number and variety of aircraft and transportation options they provide.
To this point in aviation history, a typical aircraft type certification program has focused on the constituent systems that make up the aircraft, decomposing them further and further down until reaching their elemental parts and how they interact. This approach has traditionally treated the actual communication technology as only an interface, with technology and implementation based on a decision between multiple stakeholders via an ICD and high-level requirements. This has been necessary to ensure the accurate and on-time delivery of safety-critical data between nodes. When using legacy point-to-point or bus-based data communication technologies like ARINC 429 or MIL-STD-1553, this approach has worked well enough as these technologies are relatively straightforward and proven technologies. However, as onboard bandwidth needs for safety-critical data increase, these legacy technologies are increasingly no longer capable of meeting the needs of system integrators. Ubiquitous, high-bandwidth Ethernet is the obvious solution to these needs and, indeed, it has been used for quite some time in onboard networking applications for low Development Assurance Level (DAL)/non-safety critical data. However, as Ethernet moves into high-DAL applications, the certification of the Ethernet network itself becomes a major complexity that must be addressed directly.
The development of turbulence criteria to provide early guidance for the design of vertiports is presented in this paper. For any aircraft, winds, in particular crosswinds and gusty winds, are top of mind for all pilots engaging in take-off and landing maneuvers. It is anticipated that the same will be true for VTOL and eVTOLs landing on vertiports, in particular as new vertiports are built closer and closer to urban centres. First, a review of the current design criteria for vertiports around the world related to wind is presented, highlighting the commonality between the guidance and the gaps in their content. Second, the controllability criteria that VTOL and eVTOLs will likely need to meet in the pursuit of an airworthiness certification are reviewed and their pertinence with regards to vertiport design are discussed. Third, the characters of the wind and their impact on eVTOL flights at or near take-off and landing infrastructure is explored. Finally, a set of turbulence criteria for vertiports and a turbulence index are proposed. The index includes a scale for conditions ranging from favorable for take-off and landing; to more and more demanding conditions; up to turbulence conditions to be firmly avoided.
This paper describes the methodology, involving testing and simulation activities, to assess malfunction conditions of complex systems installed on fly-by-wire vehicles, including the evaluation of their effects. This paper provides also a description about how the system malfunction tests are designed, driven by input requirements and systems capability and behavior. With respect to prior publications, this paper includes some practical test examples, based on systems monitoring, logics and alerting functions. The case study described here comes from a portion of multiple laboratory certification tests done for AW609 Tiltrotor, focused on Avionics System malfunctions. These tests and simulations are a valuable Means of Compliance with respect to applicable airworthiness rules, and a suitable means to verify the design safety requirements. Three relevant examples are presented, grouped by input requirement and safety conditions. The effect of such malfunctions is evaluated, with respect to the Avionics System output produced to keep adequate flightcrew awareness about the vehicle status.
Additive manufacturing (AM) is currently being used to produce many aerospace components, with its inherent design flexibility enabling an array of unique and novel possibilities. But, in order to grow the application space of polymer AM, the industry has to provide an offering with improved mechanical properties. Several entities are working toward introducing continuous fibers embedded into either a thermoplastic or thermoset resin system. This approach can enable significant improvement in mechanical properties and could be what is needed to open new and exciting applications within the aerospace industry. However, as the technology begins to mature, there are a couple of unsettled issues that are beginning to come to light. The most common question raised is whether composite AM can achieve the performance of traditional composite manufacturing. If AM cannot reach this level, is there enough application potential to warrant the development investment? The answers are highly dependent on the individual processors and will require significant research. Yet, there are still other common challenges that are not isolated to a singular processor. The focuses of this chapter are the capability to design and provide robust structural analysis for continuous fiber-reinforced polymer AM—two unsung aspects that can make or break this new technology as it finds its way into the aerospace market. These two unsettled issues, out of many, may require fundamental changes to the design, analysis, and manufacturing process. Without solutions to them, adoption by the aerospace industry will be limited to point design applications, thus constraining the technology to being nothing more than a specialized tool.
Validation of Mission Performance Calculator (MPC) for Airworthiness Applications of Future Vertical Lift Platforms, presentation by US Army DEVCOM AvMC.
Australia has embarked on an extraordinary reform to design, develop and implement a new and contemporary Defence Aviation Safety Framework. The program seeks to establish a single Defence Aviation Safety Authority (DASA) and issue a comprehensive and integrated suite of Defence Aviation Safety Regulation (DASR) for initial and continuing airworthiness, flight operations, air navigation, aerodromes (inclusive of ship-borne heliports) and safety management systems. While reforms of this scale can often be triggered by reviews into major aircraft accidents, such as The Nimrod Review by Charles Haddon-Cave QC in October 2009, Australia initiated the reform when new aircraft fleets were being introduced and at a time of arguably high-levels of aviation safety. The purpose of this paper is therefore to explain the compelling reason for change; providing a twenty-five-year retrospective analysis of Australia’s previous Defence aviation safety framework to give a rich picture of the difficulties faced by increased commercialization from the late 1990s, globalization in the 2000s, and the recent emergence of strict work, health and safety legislation in Australia.
As imbedded as it is in technology, the history of flight is also chock full of people stories. The history of the helicopter, one of the most versatile flying machines ever designed, abounds in such stories. This text looks at the development of Intercity Airlines Company's SG Mark VI by a unique team based for a time in Montreal, Quebec. Bernard W. Sznycer and Selma G. Gottlieb conceived one of the most advanced and innovative helicopter of its day. Designed to minimize vibrations and facilitate production, the SG Mark VI first flew in July 1947. Canada's Department of Transport awarded a Certificate of Airworthiness to a second prototype, in April 1951. The SG Mark VI was the first helicopter designed within the British Commonwealth of Nations to be so honored. Sadly, by then, American helicopters all but dominated the civilian and military markets. The SG Mark VI was abandoned during the winter of 1953-54 and both Sznycer and Gottlieb returned to the United States.
Under the Rotorcraft Structural Integrity Program (RSIP) Pilot Demonstration effort, the requirements defined in MILSTD-3063 were applied to a Future Vertical Lift (FVL) representative, model performance specification objective aircraft to demonstrate a standardized RSIP process. This paper covers application of the MIL-STD-3063 approach on SB>1 DEFIANTTM airframe structural components and presents the evolution of the resulting RSIP Master Plan. Elements of the resulting Master Plan are discussed in detail. The Master Plan is the basis for collaborative establishment of structural integrity with an efficient and effective airworthiness substantiation footprint. The discussion includes case studies of the application of logic flow to requirements in MIL-STD-3063 for the determination of specific, relevant action items to airframe structural demonstration components. Execution of this pilot effort led to lessons learned and highlighted feedback to inform the ongoing development of the MIL-STD-3063 process, through ongoing collaboration between the SB>1 DEFIANTTM team and the U.S. Army.
Inspecting an aircraft after a known or suspected lightning strike can be a tedious and subjective task. While aircraft technical manuals do provide conditional inspections following a lightning strike, these inspections tend to be broad in their approach and based solely on the presence of visual damage. This paper discusses the simple technique of tracing the lightning path through the aircraft by the use of an analog magnetometer to identify ferromagnetic parts that have been magnetized by the substantial electrical current of a lightning strike. While this technique is not novel, it is not often published as an inspection technique. Knowing the approximate path of the lightning can assist aircrews and maintainers in the identification of suspect parts that may require further inspection, repair and/or replacement thereby increasing safety and ensuring continued airworthiness of the aircraft.
As the U.S. Army endeavors to maintain overmatch capability in the global arena, Future Vertical Lift has become a high priority. In a climate that demands a more efficient and affordable acquisition process, it is imperative that structural integrity requirements are maintained as a priority to ensure initial quality, supportability, and maintainability considerations. Therefore, it is paramount that a standard practice be utilized so that structural integrity requirements are clearly understood by the Product Office, the Airworthiness Authority, and the Original Equipment Manufacturer(s). This paper highlights how the MIL-STD-3063 U.S. Army Standard Practice for Rotorcraft Structural Integrity Programs can meet these demands by laying out interrelated functional tasks in a concise manner to allow for decision makers to make sound choices with regards to structural integrity for any new developmental aircraft. The paper also details how the standard practice is being utilized to assist and guide Future Vertical Lift efforts.
As autonomous-drone and air-taxi concepts debut, legal hurdles will need to be cleared before the skies are automated. Autonomous vehicle technology literally has nowhere to go but up. At CES '19, more than 170 exhibitors showed aerial drones of various shapes and sizes. Potential use cases for these devices appear to be limitless, but technical, legal and regulatory hurdles must first be overcome. Drones are categorized by vehicle weight. The small devices weighing between 0.55 and 55 pounds (.25 kg to 25 kg) are known as Unmanned Aircraft Systems (UAS) and are lightly regulated. Drones exceeding 55 lb are regulated as traditional aircraft. Operators must obtain proper registration, licenses and certification for airworthiness.
Oxygen system integration and performance precautions are in particularly dependent on applicable sections of airworthiness requirements per FAR/JAR 25. In this document information will be provided on common principles and good practices regarding design criteria, installation, manufacturing, safety aspects and system handling during maintenance and inspection.
Over the past several years, a focus on and vision for data science in operational aviation data sets has emerged from the United States Armys Aviation Engineering Directorate (AED) team that has traditionally focused on vibration diagnostics and HUMS applications. Recently formed into a separate team under the Aerodynamics and Simulation Branch, this team has pursued the organizational, technological and intellectual challenges required to apply data science to aviation data, and to field data science products to systems under airworthiness governance. This paper provides an update on several of the specific areas of accomplishment and direction, with further detailed information referenced.
This paper provides insight into the methods used by U.S. Army Aviation Engineering Directorate personnel to assess airworthiness impacts due to changes in loads, usage, or strength, and resulting effects on calculated safe-life retirement times. Statistical analysis of system reliability for overflight of the safe-life time for components with assumed failure distributions forms the mathematical basis for the method. Topics include failure rate, baseline failure rate, percent change in system level risk, immeasurable risk, and mathematical relationships between each. Results include figures to aid in visualization and tables to enable the reader to check an implementation of the method for specific examples. The paper presents the results of analysis used to derive Weibull slope parameters based on recently developed fatigue reliability methods and available mission loads spectra. Finally, the paper presents a new method to establish life factors required to convert retirement intervals with a delta failure rate (for an airworthiness impact) into retirement intervals with immeasurable risk. Modified life factors address special cases of incompatible confidence and analysis uncertainty.
The Future Airborne Capability Environment (FACETM) Technical Standard has set the stage for avionics software reuse by establishing a computing environment for the deployment of portable software components. This reduces the rework necessary to integrate an avionics software component into multiple aviation platforms with varying operating environments. Since the evaluation and demonstration of airworthiness of software components and the systems they comprise can add significant cost and schedule impact, areas most affected by the portability of the software need to be considered in order to maximize the benefits of reuse. Existing guidance for the acquisition of airworthy software often does not specifically address the reuse of components across multiple platforms, although work is being done in this area. Within United States (U.S.) Army Aviation, airworthiness evaluators concerned with the qualification of software conceived a Reusable Verification Component (RVC) that would be portable alongside the reusable software component. This RVC could ensure proper integration and correct functionality of the component for future systems. Existing developmental processes could be leveraged when using the RVC to verify the software implementation, resulting in efficient regression testing over the software lifecycle. The U.S. Army's Joint Common Architecture Demonstration (JCA Demo) project procured a FACE software component and an RVC from two vendors that were then integrated into multiple undisclosed operating environments. This paper captures the effort, results, conclusions, and recommendations for an RVC as an outcome of the experiment.
In recent year, with the booming of Chinese economy and domestic civil air transportation market, China's aircraft manufacturers have been trying to develop their own commercial aircraft and changing from the subcontracting-manufacturer to aircraft developer, which turned to be a very hard task. One of the main challenges in front of China's aircraft manufacturers and airborne equipment suppliers is how to apply the airworthiness standards, such as ARP4754A, ARP4761, DO-178B(C) and DO-254, etc, into their engineering practice. Chinese companies are struggling in improving their capabilities to satisfy certification requirements and are making some remarkable progress these years. The paper first introduces the current status of Chinese aviation industry, and then the challenges to China's airborne equipment suppliers are analyzed. Based on these, the customization considerations of airworthiness standards and ARP4754 Practice in Chinese context are discussed.
Avionics Reference Embedded System (ARES) is a Government owned reconfigurable avionics software integration environment developed by the United States (U.S.) Army's Aviation and Missile Research, Development, and Engineering Center (AMRDEC) Software Engineering Directorate (SED). ARES was developed in support of multiple Aviation Development Directorate (ADD) Science and Technology (S&T) programs including Modular Integrated Survivability (MIS), Route Optimization for Survivability Against Sensors (ROSAS), Architecture Centric Virtual Integration Process (ACVIP), Joint Common Architecture (JCA), and Joint Multi-Role Technology Demonstrator (JMR TD). The creation and evolution of ARES was born out of the need to demonstrate an innovative software integration approach by exercising integration of 3rd party-developed software capabilities on multiple operating environments. Development of ARES utilized a Model Based Engineering (MBE) approach to implement a rapid capability integration strategy incorporating Systems Modeling Language (SysML) models incorporating Unified Modeling Language (UML), Systems Modeling Language (SysML), and Architecture Analysis & Design Language (AADL); optimization of airworthiness resources through automatic artifact generation and asset reuse; and alignment of DO-178C, DO-331, AC 20-148, and the Future Airborne Capability Environment (FACE) Technical Standard for application to Aviation Engineering Directorate's (AED's) AR 70-62 airworthiness qualification process.
The current avionics integration approach is becoming unaffordable partly due to the schedule and cost associated with integrating an avionics system into each configuration of each platform using its native interface. The United States (U.S.) Army's Aviation and Missile Research, Development, and Engineering Center (AMRDEC) Director for Aviation Development tasked the Modular Integrated Survivability (MIS) team to work with the U.S. Army Aviation Engineering Directorate (AED), the Army's airworthiness authority, to explore innovative integration approaches to streamline the integration process while still satisfying airworthiness certification requirements. AED has been engaged since the inception of the MIS Science and Technology (S&T) program. The MIS team, along with AED, has focused on developing the concept of using capability interfaces to communicate with similar avionics systems. The capability interfaces are built by abstracting the native interfaces allowing for a single integration into the platform for an entire suite of avionics systems. To build upon the capability interface approach, the AMRDEC MIS team has aligned its approach with the Future Airborne Capability Environment (FACE™) Technical Standard to enable portability and reuse of the capability interfaces across platforms. The paper discusses the time and cost challenges of the current avionics integration approach. It explores the MIS integration approach of developing and utilizing capability interfaces to integrate entire avionics system suites. The paper also discusses how incorporating the FACE Reference Architecture into the approach promotes software portability and reuse to reduce integration effort. The paper concludes by discussing the synergy realized by combining the MIS capability interface approach with the software portability enabled by the FACE Technical Standard.
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