Parking Effects on Aircraft Reliability and Flight Performance

During the pandemic period caused by Coronavirus (COVID-19) in 2020, the airlines have parked or stored their fleets partially or wholly worldwide. The International Air Transport Association (IATA) estimated a major downsize in approximately 65% of the worldwide airline fleet\u27s airline operational activity at the end of April 2020. With that said, mechanical and electrical systems, when stopped during long periods, can deteriorate by corrosion, contamination, discharge, and oxidation (Boeing, 1998). During the aircraft parking or storage process, it is not different (Airbus, 2020). This study aims to understand how much the aircraft performance and reliability are affected by parking and storage processes when these processes are correctly applied following the aircraft manufacturer\u27s manuals and instructions. The research is applied regarding the study\u27s nature, exploratory in front of the study\u27s objective, quantitative in light of the research approach since all reliability databases are numeric. The study group will apply a t-test statistical tool to compare the averages among the reliability and operational database. The results suggest a real impact on the aircraft\u27s technical performance that stopped in the parking process during this critical period for airlines. The post-pandemic findings show more than 20% of worsening in the average of failure reports in general and identify worsening in pre-established subgroups according to the aircraft\u27s downtime or age. It was also identified 5 aircraft systems that should focus on the engineering and support areas in the return of operations, by the considerable increase in failures. Durante o período de pandemia causado pelo Coronavírus (COVID-19) em 2020, as companhias aéreas estacionaram ou armazenaram suas frotas de forma parcial, ou total, ao redor de todo o mundo. A Associação Internacional de Transporte Aéreo, da sigla em Inglês IATA (International Air Transport Association) estimou uma redução de aproximadamente 65% da atividade operacional da frota aérea mundial no final de abril de 2020. Desta forma, os sistemas mecânicos e elétricos, quando parados durante longos períodos, podem se deteriorar por corrosão, contaminação, descarga e oxidação (Boeing, 1998), e durante o processo de estacionamento ou armazenamento de aeronaves, não é diferente (Airbus, 2020). Este estudo tem como objetivo compreender o quanto o desempenho e a confiabilidade das aeronaves são afetados pelos processos de estacionamento e armazenamento, mesmo quando esses processos são corretamente aplicados seguindo as instruções e manuais do fabricante da aeronave. A pesquisa é aplicada quanto à natureza do estudo, exploratória frente ao objetivo do estudo, quantitativa à luz da abordagem da pesquisa, uma vez que todas as bases de dados de confiabilidade são numéricas. O grupo de estudo aplicará uma ferramenta estatística de teste t para comparar as médias entre o banco de dados de confiabilidade e operacional. Os resultados sugerem um impacto real no desempenho técnico das aeronaves que pararam no processo 7 de estacionamento neste período crítico para as companhias aéreas. Os achados pós-pandêmicos mostram mais de 20% de piora na média dos relatos de falhas em geral e identificam piora em subgrupos pré-estabelecidos de acordo com o tempo de inatividade ou idade da aeronave. Identificamos também sistemas de aeronaves que devem focar nas áreas de engenharia e suporte no retorno das operações, pelo aumento considerável de falhas

A Formal Framework for Modeling and Prediction of Aircraft Operability using SysML

Aircraft operability characterizes the ability of anaircraft to meet operational requirements in terms of reliability, availability, risks and costs. Airlines policy must cope with operational decision-making and maintenance planning to handle the impacts of any event that generates a maintenance demand during operations. Aircraft operability is therefore considereda major requirement by each airline. The subject reaches a complexity level that deserves investigations in a Model-Based System Engineering (MBSE) approach enabling abstractions, as well as simulation and formal verification of models. In this paper, aircraft operability is modeled using Finite State Machines(FSM) supported by SysML. Simulation and model checking techniques are used to evaluate the impact of an event on airline operations using operability Key Performance Indicators (KPIs)such as reliability, availability and cost. The modeling frameworkis demonstrated on a case study of air-conditioning pack. This kind of operability analysis helps to project the potential impactof aircraft design on airline operations early in the aircraft development

Reliability and Cost Impacts for Attritable Systems

Attritable systems trade system attributes like reliability and reparability to achieve lower acquisition cost and decrease cost risk. Ultimately, it is hoped that by trading these attributes the amount of systems able to be acquired will be increased. However, the effect of trading these attributes on system-level reliability and cost risk is difficult to express complicated reparable systems like an air vehicle. Failure-time and cost data from a baseline limited-life air vehicle is analyzed for this reliability and reparability trade study. The appropriateness of various reliability and cost estimation techniques are examined for these data. This research employs the cumulative incidence function as an input to discrete time non-homogeneous Markov chain models to overcome the hurdles of representing the failure-time data of a reparable system with competing failure modes that vary with time. This research quantifies the probability of system survival to a given sortie, S(n), average unit flyaway cost (AUFC), and cost risk metrics to convey the value of reliability and reparability trades. Investigation of the benefit of trading system reparability shows a marked increase in cost risk. Yet, trades in subsystem reliability calculate the required decrease in subsystem cost required to make such a trade advantageous. This research results in a trade-space analysis tool that can be used to guide the development of future attritable air vehicles

Aircraft Operational Reliability-A Model-based Approach and a Case Study

International audienceThe 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