As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ROUTINE OPERATIONS THE LANDING LIGHT WOULD INTERMITTENTLY NOT STOP WORKING WITH THE SELECTOR SWITCH IN THE OFF POSITION. CYCLING THE SWITCH SEVERAL TIME RAPIDLY WOULD USUALLY CORRECT THE PROBLEM. AN OBVIOUS STICKING RELAY. A NEW RELAY WAS INSTALLED AND NO FURTHER DEFECT WAS NOTED. THIS IS A REAR FAILURE FOR THIS PART. ONE FAILURE HAS BEEN NOTED IN EVERY 20,000 FLIGHT HOURS FOR OUR FLEET. (K)