Aircraft Cost Research Articles

Research on Application of ERP System in Airlines

With the rapid development of civil aviation of China, it is quite important for enterprise to develop strongly, adapt to fierce competition in the air transportation market and improve the competitiveness of enterprises. For the main features of the airlines business systems, this paper explains the integration of ERP systems, the airlines operation systems and maintenance system, which optimizes the main processes of airlines and accurately realizes the single aircraft cost accounting in the ERP systems from the information collected in the airlines operation systems and maintenance system, aiming to enhance the flight punctuality rate and to ensure flight safety.

The airline perturbation problem: considering disrupted passengers

When airlines are faced with some unforeseen short-term events, they have to reconstruct their flight schedules. Although aircraft recovery decisions affect passengers, these disrupted passengers and recovering them have not been explicitly considered in most previous aircraft recovery models. This paper presents an assignment model for airline schedule recovery which recovers both aircraft and disrupted passengers simultaneously, using a rolling horizon time framework. Our model examines possible flight retiming, aircraft swapping, over-flying, ferrying, utilization of reserve aircraft, cancellation and passenger reassignment to generate an efficient schedule recovery plan. The model ensures that the schedule returns to normal within a certain time and the objective is to minimize operational recovery aircraft cost, cancellation and delay cost as well as disrupted passenger cost. The model is tested using a data-set with two disruption scenarios. The computational results show that it is capable of handling the integrated aircraft and passenger recovery problem successfully.

The turbo fan aircraft minimum cost climb technique

PurposeThe purpose of this paper is to define minimum cost technique of turbo fan transport aircraft in the presence of dynamic change of aircraft performance. Results can be practical applicable in airlines for achieving minimal operation costs.Design/methodology/approachLogarithmic differential is applied for defining conditions in order to achieve optimal Mach number for minimal climb cost. This condition is solved numerically by using Newton‐Ramphson method, to obtain optimal Mach number distribution with altitude. Conclusion about optimal top of climb (TOC) is defined after analyses for different aircraft mass and cost indexes.FindingsProposed method of minimum cost climb resulting in potential savings up to 5 per cent compared to Aircraft Flight Manual climb law. Proposed method also made correction of climb law and optimal TOC under existence of aircraft performance degradation.Practical implicationsUse of defined climb law and optimal TOC will minimize cost of en route flight profile.Originality/valueAt present, there is no definition of climb technique for minimum cost of en route flight profile, under dynamic degradation of aircraft performance. Final results are standardized to become applicable and easy to use with modern and old type of flight management system.

Empirical Evidence Relating Aircraft Age and Operating and Support Cost Growth

Abstract Since the mid-1990's, senior Air Force leaders have pointed to an aging fleet for justification to procure new aircraft. They believe rising Operating and Support (O&S) costs are inhibiting new investments and leading the Air Force into a ‘death spiral’ (Tirpak 2006). Using 11 years of data from the Air Force Total Ownership Cost (AFTOC) database, this study investigates the relationship between aircraft age and ownership Cost Per Flying Hour (CPFH) cost growth from seventy four different airframes in the Air Force's inventory. The analysis reveals that cost growth follows a ‘bathtub’ curve where the burn-in, steady-state, and end-life display cost growth rates of 6.6%, 3.1%, and 6.9% respectively. Furthermore, the variability associated with this increase follows the same functional form as the cost growth. This research suggests that very young and very old aircraft exhibit significantly higher levels of cost growth and variability, but the magnitude of the cost growth and variability for old a...

Mechanic treatment of fastener holes: The influence of compressive residual stress on the corrosion behaviour of aluminium alloys

AbstractCorrosion has a significant impact on the life cycle cost of military aircraft. Fleet experiences show that structural areas around joining elements (rivets, bolts) and faying surfaces are particularly sensitive to corrosion. During the repair currently performed the corrosion usually is blended out, the surface protection applied, the fastener inserted and a new top coat applied. Blending out corrosion often results in a reduction of fatigue life. To restore fatigue life the induction of compressive stress in the area affected is common practice. It is generally accepted that the induction of compressive residual stress extends fatigue life but its impact on the overall corrosion behaviour of alloys is discussed controversially in the literature. For this reason the influence of compressive residual stress on the corrosion behaviour was investigated in a joint experimental project. The compressive residual stress was introduced in different ways on laboratory scale and the specimens artificially weathered to simulate the effect of corrosion.

Aircraft cost modelling using the genetic causal technique within a systems engineering approach

AbstractThe paper is primarily concerned with the modelling of aircraft manufacturing cost. The aim is to establish an integrated life cycle balanced design process through a systems engineering approach to interdisciplinary analysis and control. The cost modelling is achieved using the genetic causal approach that enforces product family categorisation and the subsequent generation of causal relationships between deterministic cost components and their design source. This utilises causal parametric cost drivers and the definition of the physical architecture from the Work Breakdown Structure (WBS) to identify product families. The paper presents applications to the overall aircraft design with a particular focus on the fuselage as a subsystem of the aircraft, including fuselage panels and localised detail, as well as engine nacelles. The higher level application to aircraft requirements and functional analysis is investigated and verified relative to life cycle design issues for the relationship between acquisition cost and Direct Operational Cost (DOC), for a range of both metal and composite subsystems. Maintenance is considered in some detail as an important contributor to DOC and life cycle cost. The lower level application to aircraft physical architecture is investigated and verified for the WBS of an engine nacelle, including a sequential build stage investigation of the materials, fabrication and assembly costs. The studies are then extended by investigating the acquisition cost of aircraft fuselages, including the recurring unit cost and the non-recurring design cost of the airframe sub-system. The systems costing methodology is facilitated by the genetic causal cost modeling technique as the latter is highly generic, interdisciplinary, flexible, multilevel and recursive in nature, and can be applied at the various analysis levels required of systems engineering. Therefore, the main contribution of paper is a methodology for applying systems engineering costing, supported by the genetic causal cost modeling approach, whether at a requirements, functional or physical level.

Method for Multivariate Analysis with Small Sample in Aircraft Cost Estimation

Method for Multivariate Analysis with Small Sample in Aircraft Cost Estimation

Innovations in over-snow cargo transport

The United States Antarctic Program (USAP) is developing tractor-sled trains to haul heavy cargo 1600 km from McMurdo Station to South Pole Station. In 2003, the proof-of-concept fleet experienced poor mobility and numerous sled breakdowns when attempting to cross the Ross Ice Shelf. Based on in-situ mobility tests, we recommended several expedient changes to the sled trains: tow the sleds outside of the tractor ruts, build larger skis with elliptical noses, and accommodate sled motions via compliant bushings. The USAP adopted these recommendations, the sleds performed well, and the fleet completed its first successful cargo delivery to South Pole in December 2005. For that season, we designed and the fleet successfully trialed a novel fuel sled consisting of a transportable fuel bladder strapped onto a sheet of durable, low-friction plastic. The resulting sled costs about one-quarter that of a steel tank sled, has about one-eighth of the tare weight and increases the expected fuel delivered per tractor almost nine times. The durability of these bladder sleds over rough terrain must yet be assessed, but their high fuel-delivery efficiency, compared with the present method of aircraft delivery, is worth pursuing. For example, a seven-tractor fleet completing three round trips per season could deliver fuel to South Pole equivalent to 92 LC-130 flights while consuming about one-quarter of the fuel required for aircraft delivery. Economic analysis shows that reduced aircraft costs could payoff the capital cost of a traverse fleet within a single season.

A methodology for the assessment of unit cost drivers for commercial aircraft

AbstractPresented in this paper are the prerequisite steps in a methodology for the identification and assessment of unit cost drivers for use in the development of a new design-oriented unit cost estimation methodology for large commercial jet aircraft with minimum seating capacity of 100 passengers. The work presented here focuses on unit cost, which is a significant element of the total aircraft cost and for the initial aircraft design process in particular. The methodology aims to investigate how aircraft design properties could influence cost. Cost estimation relationships, containing a wide range of the most highly correlated parameters, are retrieved from detailed regression analysis conducted on two different aircraft generation categories. Since the methodology is based on actual cost and technical data, it is accurate both in terms of predicting the aircraft unit cost or conducting cost-comparative studies between different aircraft concepts. The emphasis in this paper is mainly on the development approach and parameter assessments, adopted towards the final unit cost estimation methodology.

Integrating Aircraft Cost Modeling into Conceptual Design

The article presents cost modeling results from the application of the Genetic-Causal cost modeling principle. Industrial results from redesign are also presented to verify the opportunity for early concept cost optimization by using Genetic-Causal cost drivers to guide the conceptual design process for structural assemblies. The acquisition cost is considered through the modeling of the recurring unit cost and non-recurring design cost. The operational cost is modeled relative to acquisition cost and fuel burn for predominately metal or composites designs. The main contribution of this study is the application of the Genetic-Causal principle to the modeling of cost, helping to understand how conceptual design parameters impact on cost, and linking that to customer requirements and life cycle cost.

Design case study for a comparative performance analysis of aerospace materials

Reduction of the life cycle cost of aircraft is the main focus of aerospace material development at the moment. By improving the performance of aluminium alloys and using other material systems such as carbon fibre reinforced plastics (CFRP), the life cycle cost can be reduced. This paper presents a design study of a pressurised fuselage section in aluminium and CFRP, focussing on the appropriate design criteria that are to be included for each material to get a sound comparison. Furthermore, a new reference for the aluminium fuselage will be presented applying new alloys and production techniques. Damage tolerance characteristics of both aluminium and CFRP are discussed, and appropriate design philosophies are presented. A correlation between residual strength and stiffening ratio is identified and used for the optimisation of the designs. It is concluded that limited fatigue damage growth and residual strength are the main design drivers for a pressurised fuselage, and the main weakness of CFRP is identified in this field, especially when looking at the compressive strength after impact and sensitivity to damages in tension. The new and improved aluminium alloys show an increase in yield stress and fracture toughness, and by laser-welding the stiffeners to the skin, the performance in compression and the fatigue life of the panel increases.

Network Centric Operations Impact on Avionics

In network centric operations, avionics on an aircraft will be both a source and destination of information. The U.S. Department of Defense (DoD) has mandated capabilities required for transforming to network centric operations. These capabilities are called out in the Joint Technical Architecture (JTA) Version 6.0 (Ref. 2). The Weapon Systems Domain, Aviation Subdomain, identifies preferred interoperability standards for communications, data links, navigation/landing aids, and identification aids. Communications, navigation, and surveillance (CNS) avionics systems and functions impacted by the JTA include nearly all avionics hardware, software, and the human system interface. Existing avionics architectures may require major changes for integration in network centric operations. A key question is whether these changes are affordable. The controller pilot data link communication (CPDLC) retrofit into existing commercial aircraft is expensive and many airlines are in bankruptcy or have a weak financial report. Most existing military aircraft have wiring installed during production, with few upgrades since the aircraft went into service. Aircraft still in the design phase will utilize a network centric architecture that will be upgradeable as technology advances provide new “plug and play” processors, displays, and sensors and the cost of new technology such as CPDLC will be built into the aircraft cost. Architecture. Network centric operations require integrated information from many avionics systems that were originally “stand alone” and implemented a function such as navigation, or had an output to the automatic flight control system. Many current avionics systems, both military and civilian, employ a federated architecture. The federated architectures are not highly integrated since they descend from stand-alone systems employed in analog avionics and first generation digital avionics. Current aircraft architectures and avionics compatibility with the capabilities required present interesting data flow challenges. Two key requirements that an architecture must provide are high bandwidth and low data latency. Technologies. Keys to implementation of net centric capabilities are software programmable radios, Gigabit Ethernet, and “smart” displays. The Joint Tactical Radio System (JTRS) software programmable radio plans to provide up to eight channels which must connect with a multiband antenna. The Gigabit Ethernet can be fiber or

REVOLUTIONARY INDUSTRIAL CHANGE IN AIR TRANSPORT — RESEARCH AND STRATEGIC APPLICATION

This paper summarizes and interprets several years of research that considered the National Aeronautics and Space Administration's assertion that the Small Aircraft Transportation System (SATS) will become an economical alternative to automobile and airline travel — a radical paradigmatic shift. However, the literature suggests that revolutionary changes to major techno-economic paradigms should not always be made in singular radical disruptions, but rather, through the commercialization of technologies in series of market niches chosen wisely. Therefore, hypothetical SATS aircraft cost and technical performance characteristics were computer-modeled to simulate SATS in the corporate aviation environment, and in the air taxi industry. Results of exploratory research based on these models are reviewed. From the standpoint of traditional Strategic Management theory, implications are offered regarding the successful incubation of this emerging industry.

Methods to reduce direct maintenance costs for commercial aircraft

Direct maintenance costs (DMC) of commercial aircraft make a significant contribution to an aircraft's cost of ownership. The aim of our research is to find out some methods to reduce DMC. The paper first points out that design and fault diagnosis are the key factors to influence DMC, disregarding factors unique to a particular airline. A new concept of R&M design – maintenance free operating period and fault diagnosis expert system are discussed in this paper, in order to reduce DMC.

Microstructure and texture evolution during solidification processing of Ti–6Al–4V

Metal-mold casting and direct laser fabrication of titanium have become topics of great interest to the aerospace industry in recent years due to the strong focus on reducing the acquisition cost of aircraft. However, little is known about the capabilities of these processes with respect to microscale characteristics such as grain morphology, grain size, microstructure, and texture/microtexture. Hence, an extensive research program was undertaken to establish the relationships between processing conditions and microstructural characteristics and to apply finite-element-method process-modeling techniques and phenomenological microstructure-evolution-modeling techniques for the prediction of microstructure during these processes. Selected results from this research are presented.

Evaluation of forecasting methods for intermittent parts demand in the field of aviation: a predictive model

Owing to the sporadic nature of demand for aircraft maintenance repair parts, airline operators perceive difficulties in forecasting and are still looking for superior forecasting methods. This paper deals with techniques applicable to predicting spare parts demand for airline fleets. The experimental results of 13 forecasting methods, including those used by aviation companies, are examined and clarified through statistical analysis. The general linear model approach is used to explain the variation attributable to different experimental factors and their interactions. Actual historical data for hard-time and condition-monitoring components from an airlines operator are used, in order to compare different forecasting methods when facing intermittent demand. The results confirm the continued superiority of the weighted moving average, Holt and Croston method for intermittent demand, whereas most commonly used methods by airlines are found to be questionable, consistently producing poor forecasting performance. We have, however, devised a new approach to forecasting evaluation, a predictive error-forecasting model which compares and evaluates forecasting methods based on their factor levels when faced with intermittent demand. A simple example is presented to illustrate the performance of the mathematical model. It is suggested that these findings may be applicable to other industrial sectors, which have similar demand patterns to those of airlines. Scope and purpose Demand forecasting is one of the most crucial issues of inventory management. Forecasts, which form the basis for the planning of inventory levels, are probably the biggest challenge in the repair and overhaul industry, as the one common problem facing airlines throughout the world is the need to know the short-term part demand forecast with the highest possible degree of accuracy. The high cost of modern aircraft and the expense of such repairable spares as aircraft engines and avionics constitute a large part of the total investment of many airline operators. These parts, though low in demand, are critical to operations and their unavailability can lead to excessive down time costs. Most airline materials managers deal with intermittent demand, which tends to be random and has a large proportion of zero values. In an effort to achieve this, the study has presented a model that could be of great benefit to airline operators and other maintenance service organisations. It will enable them to select in advance the appropriate forecasting method that better meets their cyclical demand for parts. This approach is consistent with the purpose of this study, which aims to compare different forecasting methods when faced with intermittent demand.

NASA's small aircraft costs versus automobile costs and the economic value of traveler time

This paper presents the results of a study which examined the premise that NASA's Small Aircraft Transportation System (SATS) concept will be seen as an economical alternative to automobiles, when considering the economic value of a traveler's time. Grounded in previous research into SATS Life Cycle Costs, Travel$ense software was used to examine three levels of cost of a hypothetical SATS aircraft versus that of an automobile, traveling among city pairs in Florida. On the whole, NASA's premise about the contribution of the value of time, to the validity of the SATS concept, received qualified support. Without considering the value of time, the SATS aircraft was not found to be economically competitive with autos. When considering the value of time, SATS emerged as an economically viable mode of business transportation.

Parametric Optimization of Manufacturing Tolerances at the Aircraft Surface

Up until now, aircraft surface smoothness requirements have been aerodynamically driven with tighter manufacturing tolerance to minimize drag, that is, the tighter the tolerance, the higher is the assembly cost in the process of manufacture. In the current status of commercial transport aircraft operation, it can be seen that the unit cost contributes to the aircraft direct operating cost considerably more than the contribution made by the cost of block fuel consumed for the mission profile. The need for a customer-driven design strategy to reduce direct operating cost by reducing aircraft cost through manufacturing tolerance relaxation at the wetted surface without unduly penalizing parasite drag is investigated. To investigate this, a preliminary study has been conducted at 11 key manufacturing features on the surface assembly of an isolated nacelle. In spite of differences in parts design and manufacture, the investigated areas associated with the assembly of nacelles are typical of generic patterns in the assembly of other components of aircraft. The study is to be followed up by similar studies extended to lifting surfaces and fuselage

Impact of aerodynamic surface tolerance on aircraft cost driver

The cost impact of aerodynamic tolerances on the wetted surface of an engine nacelle is considered. Manufacturing tolerance data were obtained from Bombardier Aerospace Shorts, Belfast, while the corresponding costs were calculated according to various recurring elements such as basic and overtime labour, rework, concessions, redeployment, etc., along with amortized non-recurrent costs due to jigs and tooling, machinery, etc. The cost—tolerance relations were modelled statistically so that the influence of tolerance change could be ascertained. It was found that relatively small tolerance relaxations resulted in significantly reduced costs of production but that there was a large variation in the sensitivity, at current levels. The resultant drag penalty was also predicted in conjunction with the cost—tolerance estimation to show that the operational cost effectiveness of the nacelle was increased by 0.33 per cent.

Pulsed Eddy Current Technology: Characterizing Material Loss with Gap and Lift-off Variations

Ownership costs of operational aircraft have increased steadily over the years. One of the major cost drivers is structural deterioration due to corrosion. Beyond the economics, finding and characterizing corrosion is essential for the continued airworthiness of aircraft fleets. To this end, the pulsed eddy current technique holds the potential of becoming the primary means of detecting corrosion in multilayered structures. Its wide-band frequency spectrum allows the determination of a large number of parameters, such as defect size and location. Pulsed eddy current is still considered an experimental nondestructive technique because of realistic inspection problems (e.g., probe tilting, protrusion of rivets, and thickness variations in adhesive and paint) have not been addressed in the past. Recent advances change this situation and allow pulsed eddy current to be a credible field technique.