Abstract
Maintenance activities plays an important role in the bus industry, as it affects the buses availability. The success of maintenance in the bus industry depends on the availability of critical maintenance spare parts. The non-availability of buses to take shifts often results in bus companies: (i) loosing revenues, (ii) having its customers becoming dis-satisfied, (iii) getting monetary penalties, (iv) loosing market share, and (v) possible loosing operated contracts.
The critical maintenance spare parts in the bus industry plays an important role. It ensures bus availability and also improves the safety of buses. The increasing importance of management of the critical maintenance spare parts calls for an improved forecasting strategies of the critical maintenance spare parts. This thesis focusses on evaluating the forecasting strategies and techniques of the critical maintenance spare parts in the bus industry.
The research focussed on the bus operating companies in South Africa (both operated by municipalities and private owners). The data was collected by means of questionnaires and face-to-face interviews (which were a combination of structured and unstructured questions). The research involved 840 research participants. The researcher used the computer-aided programme such as Statistical Process Software for Social Sciences (SPSS) to manipulate the data. In addition, the researcher used Ms Office Packages (i.e. Word, Excel and PowerPoint) in presenting the final results of the research.
The results of the study indicated that the bus industry uses a combination of judgemental and scientific methods in forecasting the need for spare parts for the bus industry. However, the judgemental method (in the form of the experience of the staff/trends/anticipated products usage) – was discovered to be the method widely used. The results of the study also indicated that the industry is fragmented, with different players uses different Information Technologies (IT) systems, with less data sharing amongst players of the industry, government not playing a critical role of regulating the industry, the majority of spare parts are sourced in the international markets (localisation of production is very small), and the industry is not developing at the same rate. The researcher compared the forecasting techniques used by bus industry in South Africa to those used by bus industry in the semi-developed and well developed worlds. The researcher found that in the developed bus market, scientific techniques are used to forecast the critical maintenance spare parts.
The researcher concentrated only on relatively expensive, critical parts, which are subject to field failures with operational consequences. This does not mean that the researcher disregarded non-expensive parts, which in most cases account for a large number of inventories in the bus operating industry. The reasons for not focussing on them were that (i) it is easy to determine demand and usage of less critical parts, (ii) obtaining them from suppliers often involves shorter lead times, and (iii) non-critical parts are often sourced locally. This research defers to the previous research as it addresses a number of issues: (i) risks and cost models for optimization of repairable and non-repairable parts, (ii) total life cycle of the bus, and (iii) repairing critical spare parts can be unlimited.
D.Phil. (Engineering Management)