Challenger 350
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Commercial
Situational Awareness; Communication Breakdown; Confusion
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Human Factors; Procedure
We were scheduled to do a flight from with 4 passengers. There was frost on the wings of the aircraft; and I talked to line personnel about de-icing. I was told that they would de-ice us right where we were parked; we would not have to reposition the aircraft. The First Officer and myself then briefed and discussed which de-icing checklist we were going to be using. Later when I went inside the FBO to wait on our passenger; I asked the line personnel what the Iceman frequency was; and if that was the same frequency as the FBO freq. They were taken aback by my question and told me they didn't know. Then; they said they don't even know if their headsets were functioning. I then explained that we needed to configure the aircraft before de-icing; shut down the APU and needed to do a checklist also. So I suggested that we would flash the taxi light at them as a signal when we would be ready to start the de-icing procedure.Our passenger arrived shortly after that; and we briefed them also about the fact that we were going to be de-iced. We then started our checklist; and we were only at the second step or so when the First Officer noticed the de-icing truck out of the corner of his eye. They then started spraying the right wing. No notice; nothing. The First Officer quickly shut down the APU and I hurried out of my seat to open the aircraft door to get outside. It looked like we were quick enough with the APU shutdown and no fluid had entered the exhaust. Once outside I walked over to the truck and asked why they started spraying without waiting on our all clear sign. I got no clear answer. I went back inside the aircraft and they finished the de-icing. Since I now did not trust their work method; I went back outside to do a tactical check. The driver of the truck then also walked up to me and I asked him again what happened between our conversation inside the FBO and not 30 minutes later they did not adhere to anything I said. He replied that it was hard to hear our APU noise over the noise of the de-ice truck. That is no excuse; the whole idea was to wait on our signal to start the deicing process.I do not know what else I could have done to have prevented this. I thought I was very clear upfront with our request for Type I; and I thought I was also very clear in explaining that we needed time to be configured and to finish our checklist. And more importantly; we talked about a light signal in leu of transmitting  on a frequency. I am very surprised that an FBO in a place like ZZZ does not have better trained de-icing personnel. This is a place where surely they need to de-ice often; and their personnel should have a lot of experience with de-icing procedures. What we witnessed yesterday was very unprofessional.
Corporate pilot reported deicing truck did not comply with the agreed upon deicing procedure and began before the crew was ready while the APU was running.