LAYOUT PROBLEM FOR AN AIRCRAFT MAINTENANCE COMPANY TOOL ROOM

A tool room of an aircraft maintainance company with 10 000 tools is c onsidered. These tools are borrowed by the mechanics when needed and m ust be returned before the end of shift. About 400 in-out transactions are handled by the storekeepers of the room. However, since the room is usually crowded with mechanics at their shift start/end times, the storekeepers are overloaded and significant productive manpower is hel d up in waiting for the tools, Therefore, the racks and tools in the t ool room are required to be rearranged so that the handling time of th e in/out transactions can be reduced, The racks are rearranged by heur istics and then tools are allocated to the racks according to request probabilities, which are estimated by the proportion of each tool's on -loan frequency to the total on-load frequency during December 1992, E ffectiveness is measured by comparing the total rectilinear distance t ravelled to fetch the tools requested during 11-15 January 1993 based on the proposed changes, to that based on existing rack and tool arran gement. It was found that improvement by tool allocation according to the request probabilities could reach up to 39% with the existing rack arrangement. Furthermore, minor rearrangement on the racks could also reduce the distance travelled by 12%.