Abstract: Radar radome of MA60 Aircraft is situated at the front of its fuselage, and it is a GFRP with honeycomb sandwich structure which was made by hands with the treatment of wet process. The radar radome is not only a functional device with the feature of electromagnetic wave penetrating, but also a vulnerable structural device. And water-logging of the honeycomb sandwich is one of the most severe damages. This paper combined all the fault phenomenon of electrical performance deterioration during the usage of radar radome in MA60 aircraft in outside field, and conducted simulating experiments of raining and soaking on the defective radar. By analyzing and comparing the weights and electrical performances of the radar radome before the simulating experiment as well as after that, and we found that in those situations water could infiltrated into the honeycomb sandwich through small damages (even some subtle damages) to deteriorate the electrical performances of the radar radome in a short time. Based on these experiment results, we analyzed the reasons which cause water accumulation in the honeycomb sandwich, and with the help of electromagnet theory, we studied the harms that water did to the electrical performances of radar radome; therefore, we concluded that dealing with all the outside and inside surface damages of radar radome is crucial for us to maintain its perfect alectrical performances.

Key words: radome, damage, transmitting efficiency, water intak