Working in conjunction with Mitsubishi Corporation (MC), Machinery Dept.-B succeeded in having Mitsubishi Heavy Industries, Ltd.'s Nagoya Guidance & Propulsion Systems Works (MHI Meiyu) enter into an agreement with Thai Airways International Public Company Limited (THAI) for aircraft engine maintenance service for a period of three (3) years from June 2004.

MHI Meiyu started Overhaul & Repair aircraft engines in 1960. In 1989, MHI Meiyu participated in Pratt& Whitney's PW 4000 series engine collaboration program and started to overhaul and repair some certain types such as PW4158 type engine, which belongs to the PW 4000 series.

Out of THAI's entire aircraft fleet, about fifteen (15) aircrafts of model A300 B4 are equipped and powered by PW 4158 engines.

Major overhaul and repair of an engine depends on utilization of the aircraft. In average, the normal-use engine is required to be major overhauled every 3 years. Each major overhaul and repair costs about a few million US Dollars. Although it sounds expensive, it is worth when considering safety comes first.