Lu has certainly been around the block, and has a great deal to add to PPRUNE about maintenance and reliability. His background is very strong in maintenance and support, and not at all strong in the direction of design, especially controls, aerodynamics, structures or components.
This explains his curiosity in the field of controls and design issues, and brings to question his expertise to answer those type of questions. It also explains how Lu uses maintenance instructor courses as his background for detailed design discussions, instead of typical aeronautical design texts.