Browse Topic: Fleets
On July 19, 1990, Senator Danial Inouye chaired a subcommittee to address the fate of the USMC V-22 Osprey program. Prior to this meeting, Secretary of Defense Dick Cheney, at a time of increasing fiscal constraints on defense spending, in a controversial decision, terminated the V-22tilt rotor aircraft program. However, it was resurrected by Congress. Proponents of the V-22claimed the aircraft costs were justified since it represented revolutionary technology with long-term benefits to military and civil aviation. Therefore, a study was authorized through the office of the Honorable David Chu, then Assistant Secretary of Defense for Program Analysis and Evaluation. The Institute for Defense Analyses (IDA), a Federally Funded Research and Development Center (FFRDC), was tasked to conduct the analyses. IDA conducts studies and analyses for the Office of the Secretary of Defense, the Joint Staff, the unified commands, and the Defense agencies. IDA was specifically tasked to conduct an
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.
The subject of this paper is the conceptual development of two new configurations for HEMS Operations as a new fleet concept for the European theater. Previous studies showed an increase of the required flight range for an emergency patient transport. But in conjunction with an average share of less than 30% of the flights actually with the patient. In the most rescue missions an emergency physician is transported to the scene, the patients further transport is conducted on-road by an ambulance. Considering an improved flight performance, the first DLR design study revealed a growth of the maximum take-off mass of the primary rescue helicopter of 32%. That makes the rescue helicopter inefficient for the transport of only the emergency physician. Consequently, if an ambulance is already at the scene, an emergency doctor shuttle is the sensible approach. The requirements for such a configuration are developed from a feasibility study lead by the ADAC Air Rescue (ADAC Luftrettung
This paper presents a framework with associated concepts to define a method of compliance for the failure rate requirements of the Army Military Airworthiness Certification Criteria (AMACC), Chapter 5, for fleet qualification and first flight. The fleet failure rate requirement is paraphrased as less than one structural failure in 20 million flight hours at 95% confidence and applies specifically to fatigue failure of primary structural elements (PSEs). This method of compliance assumes a reliability model sufficient to support an analytical failure rate that bounds the uncertainty arising from practical constraints of an aircraft qualification program and aims to optimize the competing objectives of safety of flight and operational capability. The requirements as defined verify that the aircraft system will perform as intended for a specified fleet life and flight test program duration and serve as the analytical basis for the assessment of emergent issues identified throughout the
Applications of Unmanned Aerial Vehicles (UAVs) are on the rise. Particularly within the healthcare sector the potential is huge as its cited as the most accepted application. This paper introduces an agent-based simulation to evaluate the network performance of UAV-based logistics networks in healthcare. The simulation is applied to a hypothetical real-world network. During a simulated day, the UAV fleet performs 212 flights, including 97 delivery flights, amounting to 4264 minutes enroute and covering a distance of 5941 kilometers. The analysis reveals average non-idle and mission utilization of 66% and 33%, respectively. The study also calculates annual network costs of EUR 2.23Mn, with a majority of it being direct costs (54.5%). Further sensitivity analysis identifies the biggest influences of battery capacity, C-Rate, and operator-to-UAV ratio on network performance and costs, highlighting these factors as critical for future optimization. Additionally, the benefit of
As military organizations internationally assess life extension and replacement actions for current legacy helicopter fleets and next generation rotorcraft are under development, novel rotor system technologies are required to fulfill challenging low-speed and high-speed flight envelopes and mission requirements. Proposed by the Department of National Defense (DND) and in collaboration with the National Research Council of Canada (NRC), a TTCP AER CP13A.1 Collaborative Project (CP) has been initiated supporting multi-nation development of numerical methods for optimizing and designing next generation main rotor blades. Four NRC laboratories collaborated to assemble a data set comprising design, performance, aerodynamics, structures, dynamics, and flight sciences elements. Acquired through research and testing, this information provides reference, technical, and engineering knowledge to support aero-structural model definition, model output validation, and the numerical optimization
Previous work documented the use of IVHMS data on the U.S. Army's fleet of UH-60 Black Hawk helicopters to update the fatigue lives of six specific components on the A/L and M models. This paper documents a significant expansion of the level of data applied to the usage spectrum, as well as applying it to all components on the aircraft. As a design spectrum for the yet to be fielded Improved Turbine Engine (ITE) equipped UH-60M, changes due to new engine capability needed to be addressed. The new spectrum has been developed and is being used for planning of flight testing. The spectrum along with flight test loads will be used to generate fatigue lives for the new aircraft. Once deployed for several years the spectrum will be reviewed to determine if any changes are needed. This work highlights what the Army considers to be the most significant issues when applying monitored usage to critical fatigue components, and rationale for dealing with issues such as insufficient data for
This paper presents a new approach, variant of the Direct Load Recognition (DLR) methodology, to estimate the main rotor (MR) pitch-link load on customer flights. The original DLR methodology is based on the combination of a harmonic decomposition and the use of Machine Learning algorithms. The DLR variant replaces the harmonic decomposition by a wavelet decomposition. The application of this paper consists in two parts. First, the comparison between the original DLR and DLR variant on prototype flight test data. Two results are highlighted in this part. The capacity of representation of the pitch-link load is better for the wavelet decomposition. The modelling of its coefficients enables to slightly improve the pitch-link load estimation, especially on the high load values having more impact on the fatigue computation. This first part allows to study the feasibility of the DLR variant to estimate the pitch-link load. The second part of this paper focuses on the application of the
Corrosion occurs in diverse environments mainly on metallic parts. Helicopters are made of a huge percentage of metallic parts and need to have several maintenance steps to guarantee its functioning and its durability. The military helicopters are flying in different kinds of environment, which cover large spectrum of severity of the atmospheric corrosion [1]. In maritime conditions, the most influencing factor is the Time of Wetness, which is a direct result Relative Humidity and Salt loading. The main material used for aircraft and that is suffering from corrosion is aluminium. There are plenty of data to follow the corrosion as a function of the environmental conditions, mainly on the sensitivity with sodium chloride, Relative Humidity, film thickness, etc... [2][3]. The maintenance efficiency on helicopters is dependent on the environmental severity. The U.S. armed forces estimate $10.2 billion in corrosion costs for their aviation and missile fleets during 2016 [4] [5] [6]. The
For the last few decades, Canada's National Research Council (NRC) has been at the forefront in analyzing dynamic systems and developing tools to construct aircraft models based on flight test data. With a fixed and rotary-wing aircraft fleet available, NRC has the capability to perform leading edge R&D System Identification (SI); this worldleading SI technology has been developed and has assisted industry partners, Department of National Defense (DND), and various universities in aircraft simulation and development. As a result, NRC has gained extensive experience in modeling aircraft using SI techniques. In collaboration with CAE, this paper demonstrates the acceleration of the NRC's current flight modeling techniques, highlighting recent advances in Artificial Intelligence (AI) and Machine Learning (ML). A new Bayesian ML software is being developed to identify a 6 degrees of freedom (6-DoF) quasisteady model using simulated flight test data. To achieve this, data from the CAE
In the last decade, in order to respond to the emerging market of unmanned applications, Airbus Helicopters has developed a generic Flight Control System (FCS) for heavy unmanned helicopters. This paper describes the development of this system from the applicable high-level requirements to the design of the redundant fail safe-operative architecture and the flight modes. A focus is made on two specific flight sequences: Automatic Take-Off and Landing from ship deck which is one of the most complex maneuvers for a drone and 4D navigation (including relative to a target). The system has been brought to a maturity level with more than 100 flight hours in unmanned configuration and a level of Validation & Verification close to a certification. The portability of the developed solution on other helicopters to derive new Unmanned Aircraft Vehicle or Optionally Piloted Vehicle is also addressed thanks to commonalities with FCS that are already in use on the Airbus Helicopters fleet.
Launch, recovery, and deck handling operations are among the most challenging tasks in the deployment of fleet piloted and unpiloted air vehicles on board of air capable ships. In today's long-lead acquisition process, some existing devices are installed on new ship platforms for which the air vehicle was not initially designed. As part of the Navy deployment process, a ship suitability assessment is conducted in the form of Dynamic Interface (DI) testing. DI testing evaluates all aspects of shipboard helicopter including suitability, compatibility, adequacy, effectiveness, safety of air vehicle shipboard Flying Qualities and Performance (FQ&P), aviation support facilities and procedures for all ship-based aircraft types. With monohulled rudder/screws steered legacy vessels, certain seakeeping and turbulent boundary properties have open-ocean performance similarities. When faced with a deployment target ship producing different ship properties, a systematic approach to adapt to the new
A limited flight load survey was performed on a fleet representative UH-60L aircraft flown with various degrees and combinations of dynamically imbalanced blades. Blades selected for this test ranged in both positive and negative severity of pitching moment slope values to substantiate rotor smoothing efficacy and the effect on dynamic component oscillatory loads for dynamically imbalanced blades compared to a baseline of nominally balanced blades. For every component analyzed, greater than 70% of the maneuvers presented showed an increase in structural loads in the unbalanced configuration compared to the baseline balanced blades. Most components and maneuvers that did experience an increase in loads remained non-damaging. However, the damper experienced several maneuvers where an increase in loads may have indicated a change in fatigue lives. Based on a colloquial rule of thumb.
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