According to equivalence principle, we cannot distinguish gravity with inertial force. Let's assume that there is space shuttle which contain observer and electron. There is some force that is gravity or inertial force that we cannot distinguish. But if the force is gravity, electron will not emit electromagnetic wave.(Both of case, electron is not moving in observer's viewpoint.) However, if it is inertial force it will emit electromagnetic wave. It does not match with the principle. What is wrong in my thought?