Wireless Avionics Intra-Communication (WAIC) is the future avionics communications, which will substitute wire communication in a single aircraft. The WAIC systems do not provide any communication between air-to ground, air-to-air, and air to satellite. The WAIC systems are designed solely for enhancing efficiency and reliability inside the aircraft. The purposes of the system are monitoring, controlling, and communicating avionics in the aircraft, such as landing gear, wings, nacelles, vertical stabilizer, engine, etc. So, that system requires exclusive network for operation of the aircraft. The 22-23 GHz frequency is the candidate for WAIC system. It has sharing scenario with other systems, such as Fixed Service, Aeronautical Mobile service, Radio Astronomy, and EESS (passive) system. This paper simulates interference between WAIC and EESS (passive) systems. The interference between the two systems are the compatibility scenario of sharing study. The simulation scenario is being studied when the aircraft crosses the main beam of the EESS (passive) systems. Then, the results will be analyzed whether WAIC system interferes the EESS (passive) systems or vice versa. The simulations result show that the EESS (passive) systems do not cause harmful interference to WAIC system. So, the frequency band 22-23 GHz is compatible for WAIC system.