As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKEOFF AT ROTATION, RECEIVED A MOMENTARY NR 2 ENGINE FIRE WARNING. ALL ENGINE PARAMETERS WERE NORMAL. RETURNED TO DEPARTURE FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOOTING REVEALED THE CFDIU AND NR 1 FWC NOT FUNCTIONING PROPERLY. REPLACED CFDIU AND NR 1 FWC, OPERATIONAL CHECK OK.