As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS FLYING APPROX 100 AGL AT 20 KNTS, FIRE NOZZLE BLEW OFF THE BOTTLE GOING THROUGH THE LT FWD WINDSCREEN. PILOT MAINTAINED CONTROL AND LANDED. BELIEVE THE HEATER VENT WAS BLOWING HOT AIR ON THE EXTINGUISHER, CAUSING THE PROBLEM. RECOMMEND RELOCATING THE FIRE EXTINGUISHER MOUNT FROM NEAR HEATER DUCTS.