EVALUATION OF SCHEDULED INSPECTIONS (PERIODIC) OF FIXED-WING AIRCRAFT USING DATA ANALYSIS AND UNIFIED MODELLING TECHNIQUES

Abstract

Schedule inspection processes are primarily designed and used to enhance the life of aircraft and fitted assemblies inside through set maintenance activities developed. Second objective set for these processes is to reduce the down time of aircraft during day to day flying activities so that operational designed objectives are achieved. Organizations which are running these inspection processes they are with the missions to keep these processes to the level where they impart value addition in to the aircrafts. Managing of these processes is being ensured through held resources utilization. These inspection processes demand change when their process structures deviate from the design with the time and feel difficulty in meeting the specified standards. This situation was observed in fix wing aircraft organizations where the un-serviceability due to schedule inspection process of the fleet started floating between 8 - 15% resulting high down time of aircrafts during inspection completion and low fleet serviceability. Therefore this study was conducted with the question to reduce high down time of the inspection process in completion and improving the fleet serviceability through data analysis and unified modeling techniques. The objectives set for this study were process description, modeling, finding out the total maintenance and process activities involved, sequence of flow, analysis of the conducted inspection processes, working out constraints involved in high down time of the process and recommendation of workable solutions for process time and aircraft fleet serviceability improvement. In order to achieved fruitful data we selected complete fleet of aircraft, focused all maintenance organization conducting inspection process and snapshot of two years time period from 2011 to 2012 for inspection process conducted. Than three approaches were adopted, in first approach process static characteristics were studied through CIMOSA modeling and SMED single minute exchange of die than process major factors analysis with respect to quality, waste, variance, inventory requirement vs. delivery , process dynamic characteristics and finally process dynamic characteristic analysis through process conduct modeling, CLD causal loop developments and process rearrangement approaches. Process modeling helped out in finding out domains, business processes and activities involved. Findings showed mixing of maintenance and process activities and deviation of process structure. Application of SMED helped in bringing the process back to designed structures. Presence of variances in process quality, waste and inventory deliveries has been observed as major issues along with other variables which were part of vii the process as well as maintenance system dynamics. Process dynamic study and modeling further provided a way of diving into different process stages to analyze the issues and related constraints. CLDs highlighted exact factors involved and fruitfully reflected interrelation between the variables and causes. Adopted theoretical framework provided a solid base to analyze the issues and constraints revolving around the inspection process in the maintenance system and helped out in developing remedial practical work model in the light of process, maintenance system and managerial approaches rearrangement to overcome high down time of aircraft during schedule inspection (periodic) completion and fleet serviceability issue. High down time of the process is expected to be brought down from months and weeks to 8 days whereas serviceability improvement to 10 percent of the fleet. Knowledge areas developed during this effort were CIMOSA Modelling of the aircraft schedule inspection process, implementation of SMED process leaning approach in schedule inspections base on work piece (aircraft) instead of work station and development of CLDs related to schedule inspection process conduct.