As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BLOWER BECAME NOISY. FOUND 5 EACH FAN BLADES MISSING (P/N 2100900-25). REMOVED BLOWER FROM AUX HEATER (P/N 6214434-53). FOUND BLADES IN AUX HEATER, ALSO FOUND AIRFLOW SWITCH VANE. SUSPECTED THE VANE CAME OFF THE AIRFLOW SWITCH ASSY CAUSING THE BLADES TO BREAK OFF OF THE FAN/BLOWER ASSY. SUBMITTER STATED THE VANE TO SWITCH ATTACHMENT SHOULD BE OF A BETTER/STRONGER DESIGN.