Cycletime Reduction for Naval Aviation Deports

A considerable amount of valuable operational life of an frontline aircraft can be conserved and effectively utilized for routine operational requirements, if component replacement downtime can be avoided during the operational cycle of an frontline aircraft. Component replacement downtime compounds to the existing scheduled routine maintenance downtimes and at times it extends much longer as certain critical components replacements warrants for a series of post replacement checks during flying prior declaring aircraft fit for routine operational commitments without restrictions. Hence optimal scheduling of the component replacement periodicity or avoiding component replacement during aircraft operational life always contribute to the increase in the operational exploitation of an frontline aircraft. This paper discusses the various downtime associated with the routine aircraft inspections during the operational cycle of aircraft. The paper also provides a brief on the various methods and tools prescribed in Maintenance Repair and Overhaul agencies undertaking major overhaul / inspection of aircraft in scheduling the component life, with an aim to achieve increased operational exploitation time during frontline exploitation.

2010

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2004

Successful military mission planning and execution depend critically on equipment serviceability and resupply. Due to the stochastic nature of demands, the forecast of optimal spares and resources needed to guarantee the level of serviceability is a complex problem, especially in a multi-echelon setting. In this paper, we propose a decision-support concept and software tool known as Corrective Maintenance Optimizer (CMO) that helps to optimize system availability, through proper allocation of spare parts, both strategically and operationally.

Thesis Advisor: John Osmundson Thesis Associate Advisor: Alice Crawford ii THIS PAGE INTENTIONALLY LEFT BLANK i NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. 239-18 298-102 REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instruction, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington DC 20503.

2000

The 1998 Department of Defense (DoD) Logistics Strategic Plan directed a sweeping program to reform the "business" of the DoD. A key component of the plan is that inventories be established at the lowest possible levels and be positioned to permit rapid delivery to the customer. In response, the Marine Corps has established a "virtual float" concept that seeks to reduce inventory levels for secondary repairables (SecReps). We show through a simulation model that the Marine Corps should not expect large savings from a virtual float operating with a lateral transfer inventory policy. For the items we selected, additional transportation costs for lateral transfers almost entirely eliminated savings due to reduced inventory. We also address organizational issues involved with a centralized system. 14. SUBJECT TERMS Marine Corps Inventory Management, Secondary Repairables, Virtual Warehouse, Logistics, Supply Chain Management, Modeling and Simulation 15. NUMBER OF PAGES "" 68 16. PRICE CODE 17. SECURITY CLASSIFICATION

2021

… of the 32nd conference on Winter …, 2000

The Argentine Air Force and the Brazilian Navy recently added the Douglas A-4 Skyhawk aircraft to their military services. Each country maintains its own limited repair facility and spare parts inventory. Major repair work (depot-level maintenance) must be sent to the manufacturers in the United States, and the long repair cycle times adversely affect military readiness. It is critical to implement an effective spare parts management system to compensate for such long repair cycle times. We developed a simulation model to study the impact of consolidating aviation component spare parts inventory management and reducing transportation cycle times. Our results indicate that both countries will greatly benefit if they collaborate on the inventory management of their A-4 fleet maintenance. Their benefits will be significantly increased if they change the sea transportation mode to air transportation for transporting avionic components back and forth to the United States for repair.

Naval engineers journal, 1999

A major goal of the US Navy's Fleet maintenance and modernization strategy is to reduce the cost and time of ship availabilities, while improving the quality of the work performed. A pilot project was commissioned by the Commander Naval Surface Force ...

This thesis analyzes the impact of reducing transportation cycle time and consolidating aviation electronic component inventory management on the operational availability of the Brazilian Navy and Argentine Air Force A-4 fleets. The research is based on a scenario where the Brazilian Navy operates twenty A-4 aircraft, while the Argentine Air Force operates thirty A-4s, and both countries rely on manufacturers in the United States for depot-level maintenance. The transportation turn-around-time is extremely long and the cost of some inventory items is very high. A simulation model was developed representing the repair process of a selected group of A-4 critical electronic components. This particular model provides an effective managerial resource for long-term decision making to improve the readiness of aircraft fleet for both countries. We also developed a multiple regression analysis model (metamodel) to find the relationship between spare inventory levels and the operational avail...

—This paper considers the effect of fleet size on a joint policy of maintenance and spare parts inventory when spare parts are of varying quality. We consider identical one-component systems subject to age-based replacement, and with a single ech-elon periodic review spare-parts policy. The joint policy is opti-mised with regard to the long-run total cost per unit time, where the cost components include both replacement and inventory related costs. In particular, we are interested in the effect of spare parts quality and the size of the fleet on the variability in the demand for spare parts. Furthermore, the effects of changing lead time, different failure characteristics, and simultaneous deployment of the systems over a finite horizon on the optimal joint policy are investigated. We develop a stochastic simulation model to investigate these effects. We find that the scale effect varies with the quality of spare parts: the poorer the quality of spare parts, the smaller the scale effect. Our approach allows the value (e.g. cost of poor quality spare parts) in spare parts provisioning for maintenance to be quantified. Index Terms—Age-based replacement, maintenance quality, mixtures, spare parts inventory, supply chain management.

International Journal of Services and Operations Management, 2011

Preventive maintenance (or overhaul) is crucial for military aircraft operations because it dictates the mission readiness level and aircraft operating costs. For example, preventive maintenance not only improves the lifetime aircraft reliability/safety by avoiding unexpected equipment failure and downtime, but it also enhances the efficiency of managing spare-part by planning the replacements and replenishment of spare parts within the predetermined time interval. Despite such benefits, preventive maintenance may not be economical, unless its schedule is determined in such a way that its overall preventive maintenance costs including costs associated with the purchase of spare modules is less than the total costs of corrective actions including downtime/idle costs, repair costs, and mission failures. With that in mind, we propose a dynamic goal programming (GP) model that aims at determining the optimal number of spare modules, while meeting the scheduled due dates for preventive maintenance under budget constraints.

IIE Transactions, 2000

In this paper, we study the operational availability of a complex technical system consisting of several components. The components are subject to breakdowns, and hence for each component a limited number of spare parts are held in stock. If a system's component fails and it can not be replaced immediately, due to a lack of spares, the system becomes unavailable until a new component is installed. Failed components are disposed of and hence, to keep the spare parts stock at an appropriate level, new components have to be purchased. We assume that only a limited annual budget is available for procurement, while any further procurement requires a considerable lead time. We investigate at an aggregate level what budgets are needed to attain a target availability level for the system. In addition, we develop various operational strategies for spending the annual budget during each year. Numerical results indicate that the so-called Balance Focussed strategy provides the best results in terms of system availability as a function of time.

2008 6th IEEE International Conference on Industrial Informatics, 2008

Airlines can minimize the chances of flights arriving at airports with failed components and no replacements by positioning spare components at strategically selected airports. In this paper, we describe a high-fidelity simulation system that can simulate component failures, replace-and-repair cycles, and inventory re-balancing policies in global commercial passenger flights. This simulation system is used together with other modules such as a user interface and an optimizer to provide inventory management and decision support for airlines or Maintenance, Repair, and Overhaul (MRO) service providers. We present some results from simulating failures of critical and noncritical spare components and show how they can be of use for decision support in the inventory management.

2012

Avoidable unscheduled maintenance events and unnecessary spare parts deliveries are mostly caused by an incorrect choice of the underlying maintenance strategy. For a faster and more efficient supply of spare parts for aircrafts of an airline we examine options for improving the underlying logistics network integrated in an existing aviation industry network. This paper presents a dynamic prediction model as decision support for maintenance method selection considering requirements of an entire flight network. The objective is to guarantee a high supply of spare parts by an optimal interaction of various network levels and thus to reduce unscheduled maintenance events and minimize total costs. By using a prognostics-based preventive maintenance strategy unscheduled component failures are avoided for an increase in availability and reliability of the entire system. The model is intended for use in an aviation company that utilizes a structured planning process based on collected fail...

We consider a maintenance shop that is responsible for the availability of a fleet of assets, e.g., trains. Unavailability of assets may be due to active maintenance time or unavailability of spare parts. Both spare assets and spare components may be stocked in order to ensure a certain percentage of fleet readiness (e.g., 95%), i.e., having sufficient assets available for the primary process (e.g., running a train schedule). This is different from guaranteeing a certain average availability, as is typically done in the literature on spare parts inventories. We analyse the corresponding system, assuming continuous review and base stock control. We propose an algorithm, based on a marginal analysis approach, to solve the optimization problem of minimizing holding costs for spare assets and spare parts. Since the problem is not item separable, even marginal analysis is time consuming, but we show how to efficiently solve this. Using a numerical experiment, we show that our algorithm generally leads to a solution that is close to optimal, and we show that our algorithm is much faster than an existing algorithm for a closely related problem.