This may be what the A340-300 looks like at first. In 1986, when Airbus was still designing A340, IAE gave Airbus a super fan version of V2500, which was still under design. Compared with -CFM56, the noise was reduced by 50% and the fuel consumption was reduced by 20%. What is even more shocking is that the bypass ratio of this engine is as high as 20:1! In contrast, the engine with the highest bypass ratio–PW 1100 G has a bypass ratio of 11:1. From this point of view, this engine has epoch-making significance. At first, Airbus was skeptical about these exaggerated data, but when it saw the technical support of Rolls-Royce, Pratt & Whitney and Skyfighter behind IAE, the skepticism vanished immediately. But while Airbus is building the A340 in full swing, the IAE side has encountered a big problem.Because the gear set, an important part of this engine, has been calibrated with some outrageous data at the beginning of the design, which makes the gear set particularly high in strength. However, it was impossible to manufacture such a gear set with the materials and technical level at that time. So when Airbus built the fuselage and wings of the A340 and asked the IAE for the engine, the IAE said that I couldn't build it at all, and the previous ones were all lies. The forced Airbus can only go to CFM and ask them to upgrade CFM56 so that it can be carried on A340.