The pre-flight safety inspection shall include a visual check of the markings on the motor(s) for proper impulse and delay. At the request of the contestant, the motor inspection may be postponed until after the flight. However, if it is postponed, the part of the model containing the motor must be returned and the motor class determined by visual inspection. Rule 10.4 shall not apply and if the motor type can not be determined, then the flight is not official.