Santa Ana, CA I was a crew chief with HMH-361 out of MCAS Santa Anna at the time. We had just completed mountain training and were returning home. We encountered the aircraft at an airfield in Nevada where we were to RON and refuel before heading back to Santa Anna. The wind was picking up and my first mech I noticed that the crew did not secure the aircraft so he and I did the tie down. While doing so we noticed a black BIM on a main rotor blade indicating a possible crack in the blade spar. We informed the tower of the condition of the aircraft and followed up tracking the crewchief down in town and informed him of the black BIM and the danger of flying an aircraft with the condition. The next morning when we returned to our aircraft for the flight back to Santa Anna the aircraft was gone. We didn't learn of the crash until we arrived at Santa Anna and were met by investigators. I am still bothered to this day that there was more we should have done. HMH-361
