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【范围】
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This document describes a life cycle cost model for commercial aircraft composite structure. The term life cycle cost used
herein, refers to the airline costs for maintenance, spares support, fuel, repair material and labor associated with
composites after introduction into service and throughout its useful life. This document contains the equations that can be
programmed into software which is used to estimate the total cost of ownership aircraft, including structure. Modification
costs and operating costs are estimated over a specified life (any period up to 30 years). Modification costs include
spares holding, training, support equipment, and other system related costs. Annual operating costs include: Schedule
interruption, fuel, spares, insurance, and maintenance. Maintenance costs are separated by scheduled maintenance or
unscheduled damage, or can by grouped into the typical organizations of line, shop, and hangar maintenance. This
Lifecycle Cost allows users to evaluate the impact of Service Bulletins, potential design changes, changes in maintenance
programs, or effectiveness of maintenance operations.
1.1 Purpose
This document describes a way to estimate Maintenance Life Cycle Cost (MLCC) using a model that is a consensus
among airframe manufacturers, airlines maintenance organizations, and repair stations. The CACRC is co-sponsored by
the Air Transport Association (ATA), the International Air Transport Association (IATA), and the Society of Automotive
Engineers (SAE), which acts as secretary and publishes documents. Since this document is in the public domain, it can
be used by Original Equipment Manufacturer’s (OEM), suppliers, and airlines who desire to estimate these costs for
internal use or to communicate externally.
Some of the potential changes that can be justified with the MLCC model include: Service Bulletin implementation, design
changes during original production, optimization of airline maintenance programs, overhaul turn-times reduction by
additional investing in tooling or facilities, reliability improvements, overhaul program justification, additional training
justification, or nearly any other component or operational change.
The CACRC goal for this document is to provide:
a. an educational tool for designers describing life cycle costs,
b. a tool for use by airlines and OEM with which to carry out trade studies that are representative of the cost of airline
maintenance, and
c. A standard model that is a consensus of the CACRC members that will hopefully lead to a common language spoken
by various airlines amongst themselves and to the various OEMs or suppliers.
Since the actual cost must be calculated with many equations, this document is intended to act only as a blueprint or plan
for software that can be developed to meet the specific needs of the using companies. The features of such software can
vary considerably, so we have tried to suggest desirable options. Sometimes the optional features are enhancements to
increase functionality, and sometimes they are desired to accommodate the different methods airlines use to account for
cost and/or gather reliability information. In support of this goal, Boeing has created an MS Excel-based file which
implements the equations in this document, available from the SAE.
1.2 Background
This task grew out of a concern by the CACRC that the changes identified by the Design Task Group (see Guide for the
Design of Repairable, Maintainable and Reliable Composite Structures - SAE Document AE-27) that could reduce airline
burdens were economically unjustifiable and were therefore not implemented. Often this was due to a lack of cost data
available to the aircraft designer for anything other than original production cost and weight (and associated fuel burn).
The Design Task Group then examined the existing LCC models used in design trade studies and discovered that they
universally focus on Line Replaceable Units (LRUs). LRUs account for a large portion of airline cost, and are the most
unreliable as defined by the commonly used measures of MTBUR or delays and cancellations. However, existing LCC
models do not adequately deal with structure, which sometimes is not removable but repaired on the aircraft, and
therefore not captured in the usual measures.
This MLCC model focuses on the system life cycle from the airline perspective, especially the operational and support
costs. Unlike systems engineering or at aircraft manufacturers, this MLCC excludes costs of research and development,
production, retirement and disposal - except as these costs are reflected in the acquisition costs from the airframe
manufacturer or in airline overhead. Since this model is intended to reflect the cost to the airline, all costs are from the
airline perspective which often differs from the OEM costs. For example, the price of a spare part for the airline may be
much different than the manufacturer’s cost to produce it or to procure it.strRefField
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