Benchmarking the best practices of Lean Six Sigma in aerospace industry in India: a longitudinal multiple case analysis and roadmap for deployment

Purpose This article intends to comprehend the Lean Six Sigma (LSS) approach adopted in the aerospace industry in India for process improvement. This research has the objective of determining LSS deliverables such as Voice of Customer (VOC), Key Performance Indicators (KPIs), Critical-to-Quality (CTQ), project approach, deployment strategies and tools and techniques used to execute the project. Design/methodology/approach The study adopted an exploratory research methodology and a multiple case study analysis to draw robust inferences. The research is carried out in the Indian aerospace industry and analyses five case studies. The case studies were collated from the company via a case study protocol with pre-defined criteria. Also, a semi-structured interview is conducted with the stakeholders of each case study to determine the deployment strategies followed during the respective projects. Findings It is reconfirmed that LSS is crucial in the aerospace industry, particularly in engine and gear shops, to reduce rework and rejections. Also, it was found that cost and time savings are essential KPIs. Some LSS projects require multiple CTQs for process improvement in aero industries. The DMAIC approach is used for project execution, with the Design of Experiment (DOE) being an essential tool. Top management engagement, effective HRM practices, customer focus, cross-functional collaboration and clear roles are essential for successful LSS projects. Eventually, a road map was developed based on the analysis of multiple case studies. Research limitations/implications The study is focused on the aerospace industry in India, which may limit the generalizability of the findings to other industries or regions. The small sample size and reliance on qualitative data through semi-structured interviews may introduce subjectivity. Additionally, the long-term effects of LSS implementation, particularly in the context of evolving technologies, were not fully explored. Practical implications This study provides actionable insights for aerospace companies and related organisations to enhance quality and operational performance. The developed roadmap offers a practical guide for LSS deployment, helping organisations improve efficiency and competitiveness, especially in an era of economic slowdown and high competition. Originality/value The study reveals similarities and differences in LSS deliverables in Indian aerospace industries, creating a roadmap and tool matrix for project execution and serving as a template for manufacturing industries.