biscuit74
Using GPS coordinates and assuming the flight was at maximum distance while on the NW heading, the max distance from HNL was just under 17 NM at an altitude of around 1200 ft. That distance is well within the range capabilities of a VHF comm and there were no line-of-sight obstructions.
Regarding the parties thinking each other had finished, I think back to my initial flight training with a 180 ch comm, handheld microphone and cabin speaker, where the CFI insisted on the use of "over" for every radio transmission. "Over" is still in the AIM as approved radio phraseology but is optional. Imagine how its use would have untangled the communications in this accident.