As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF, AT APPROX 1,000 FEET AGL, THERE WAS A FIRE WARNING ON THE NR 1 ENGINE. THRUST LEVER RETARDED, LIGHT REMAINED ON. EMERGENCY DRILL COMPLETED AND LIGHT EXTINGUISHED AFTER FIRE BOTTLE DISCHARGED. AC RETURNED AND LANDED WITHOUT FURTHER INCIDENT. THERE WAS NO EVIDENCE OF A FIRE. MAINT FOUND THE FAULT IN THE NR 1 FIRE DETECTION B SYS. (TC NR 20080418002)