Enhancing System Predictability and Profitability: The Importance of Reliability Modelling in Complex Systems and Aviation Industry (original) (raw)
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Aircraft operational reliability—A model-based approach and a case study
Reliability Engineering & System Safety, 2013
The success of an aircraft mission is subject to the fulfillment of some operational requirements before and during each flight. As these requirements depend essentially on the aircraft system components and the mission profile, the effects of failures can be very severe if they are not anticipated. Hence, one should be able to assess the aircraft operational reliability with regard to its missions in order to be able to cope with failures. We address aircraft operational reliability modeling to support maintenance planning during the mission achievement. We develop a modeling approach, based on a meta-model that is used as a basis: (i) to structure the information needed to assess aircraft operational reliability and (ii) to build a stochastic model that can be tuned dynamically, in order to take into account the aircraft system operational state, a mission profile and the maintenance facilities available at the flight stop locations involved in the mission. The aim is to enable operational reliability assessment online. A case study, based on an aircraft subsystem, is considered for illustration using the Stochastic Activity Networks (SANs) formalism.
A New Aircraft Maintenance Approach Based on the Markov Chains
ANNALS OF THE ACADEMY OF ROMANIAN SCIENTISTS Series on ENGINEERING SCIENCES
In the past, traveling by plane was a luxury, today it is one of the most desired transport options in the world, being at the same time accessible and safe. In the contemporary aviation industry, for an airline to remain competitive, means to carry out as many aeronautical activities as possible without any incidents. Technical problems play a significant role in establishing the root causes underlying the efficiency of an aircraft. Considering the systems complexity involved, maintenance can be difficult without an aircraft health monitoring system over time. This study aims to provide a methodology for early identification of an aircraft failures, in order to provide specific predictive maintenance. Over the 12 months, two critical systems belonging to a transport aircraft were monitored and with the help of the Markov chains model, the probability of those systems to fail in the foreseeable future was calculated.
Modeling Aircrafts Operational Reliability
2011
The success of an aircraft mission is subject to the fulfillment of some operational requirements before and during each flight. As these requirements depend essentially on the aircraft system components and the mission profile, the effects of failures can be very significant if they are not anticipated. Hence, one should be able to assess the aircraft operational reliability with regard to its missions in order to be able to cope with failures. This paper addresses aircrafts operational reliability modeling to support maintenance planning during the mission achievement. We develop a modeling approach to represent the aircraft system operational state taking into account the mission profile as well as the maintenance facilities available at the flight stop locations involved in the mission. It is illustrated using Stochastic Activity Networks (SANs) formalism, based on an aircraft subsystem.
The paper will provide a lifecycle cost-benefit analysis of the use of Prognostics and Health Management (PHM) systems and a conditioned-based maintenance (CBM) concept in future aircraft. The proposed methodology is based on a discrete-event simulation for aircraft operation and maintenance and uses an optimization algorithm for the planning and scheduling of CBM tasks. In the study, a 150-seat short-range aircraft equipped with PHM and subject to a CBM program will be analyzed. The PHM-aircraft will be compared with an Airbus A320-type of aircraft with maintenance expenditures equivalent to a conventional block check maintenance program. The analysis results will support the derivation of technical and economic requirements for prognostic systems and CBM planning concepts.
The Effects of Aircraft Preventive Maintenance on Reliability
2012
Preventive maintenance can be described as maintenance of equipment or systems before fault occurs. The main goal of maintenance is to avoid or mitigate the consequences of failure of equipment. It also improves reliability, decreases cost of replacement and system downtime. Preventive maintenance helps provide high level of availability of system function and obtains great return on investments of hardware and software. However, very frequent application of preventive maintenance is not economical though. In order to obtain optimum benefit, this maintenance should be done at proper times. This study aims at explaining the importance of preventive maintenance mathematically. The mean time to failure (MTTF) or the mean time between failures (MTBF) is taken as the reliability criteria. The reliability values obtained when preventive maintenance is applied and not applied are compared to the MTTF.
Modeling Aircraft Operational Reliability
Lecture Notes in Computer Science, 2011
There has been considerable debate over organizational learning strategies as a worthwhile endeavor. This paper examines the issue within the context of High Reliability Organizations (HROs) through a recent ethnographic study that focused on organizational learning and its role in understanding of the dynamics of operational reliability. A review of the literature examines factors that influence organizational learning effectiveness within the context of the Sullivan-Beach model (Sullivan & Beach, 2009), which provides a conceptual framework from within which the dynamics of High Reliability Organizations (HROs) can be explained. Empirical data was gathered over a six month period in a high reliability environment supporting US Navy operations. An operational failure and the organization's response are analyzed using the Sullivan-Beach model. The analysis assisted in identifying factors that led to the operational failure and the remedial action that ultimately resulted in a dramatic improvement in operational reliability. The findings of the study support the notion that effective organizational learning strategies are critical to operational reliability, particularly in recovering from operational failures or preventing them altogether (Sullivan, 2007). In addition, the discovery of the Organizational Learning Loop within the Sullivan-Beach model suggests that success and failure with organizational learning depends on the... Read complete abstract on second cover page.
IEEE Transactions on Engineering Management, 2000
Reliability improvement is the conceptual norm but has not been achieved by all sectors of industry. The U.K. aerospace industry is one that has aspired to make the transition from a culture of reliability demonstration to enhancement. This paper presents action research that examines the challenges facing this industry. A statistical model is developed to help measure the likely impact of failure modes on operational performance, hence providing a basis for managing the enhancement process. The model, which has general applicability to other product development processes, is stated and justified. The industrial interventions are described and an analysis of findings is presented. The proposed model is better than traditional approaches because it provides a systematic process to capture and integrate data from different sources to estimate reliability by directly measuring the engineering improvement achieved through product design and development. The estimates can be used to inform a traceable coherent argument about the level and growth in reliability to management and the customer as well as to provide insight into the impact of alternative engineering modifications to the design team. The modeling process has contributed to the partial transition to reliability enhancement of a consortium of companies who have changed their standard operating procedures to reflect the lessons learned from the research intervention. The insights gained contribute to an understanding of how the U.K. aerospace industry is changing its management of reliability enhancement in design.
Modeling for reliability optimization of system design and maintenance based on Markov chain theory
Computers & Chemical Engineering, 2019
Motivated by the reliability/availability concerns in the design and operation of air separation plants, this paper proposes an MINLP model that represents the stochastic process of system failures and repairs as a continuous-time Markov chain, based on which it optimizes the selection of redundancy and the frequency of inspection and maintenance tasks for maximal overall profit. The model explicitly accounts for every possible state of the system, which gives it the potential of incorporating various types of design and operational decisions while causing difficulties in scaling up. Therefore, effective decomposition and scenario reduction methods are also proposed in the paper. A small example with two processing stage is solved to demonstrate the impact of incorporating maintenance considerations. In contrast to directly solving the original MINLP model, the decomposition and scenario reduction methods are applied to this example and is shown to have drastically improved the computational efficiency. Moreover, a larger example with four stages, which is not directly solvable, is also successfully dealt with using the proposed algorithm. Lastly, we show that the proposed model and algorithm is capable of solving the practical problem of the air separation process, which features multiple stages, potential units and failure modes.
The Importance of Preventive Maintenance in terms of Reliability in Aviation Sector
Aircraft is a system that requires high reliability levels throughout flights. Preventive maintenance procedures are applied to maintain this reliability at an optimum level. The higher frequency of preventive maintenance applications means higher reliability level; however, very frequent application of preventive maintenance is not economical though. In order to obtain optimum benefit, this maintenance should be done at proper times. This study aims at explaining the importance of preventive maintenance mathematically. The mean time to failure (MTTF) or the mean time between failures (MTBF) is taken as the reliability criteria. The reliability values obtained when preventive maintenance is applied and not applied are compared to the MTTF.