B767 CREW EXPERIENCED A LEADING EDGE FLAP ANOMALY SHORTLY AFTER TKOF AND ELECTS TO RETURN TO THE DEP ARPT.

Narrative

DURING THE AFTER TKOF CHKLIST THE FLAP INDICATOR STARTED FLICKERING BTWN 0 AND 1. AN ELECTRICAL NOISE WAS COMING FROM THE OVERHEAD PANEL IN UNISON WITH THE FLAP INDICATOR MOVEMENT. RECEIVED AN EICAS MESSAGE 'LE FLAP ASYM' OFF AND ON WITH THE NOISE AND NEEDLE INDICATION. THEN GOT EICAS MESSAGE 'LE FLAP DISAGREE.' BOTH MESSAGES APPEARED ONLY IN CONJUNCTION WITH THE SOUND IN THE OVERHEAD PANEL AND THE NEEDLE MOVEMENT. TALKED WITH MAINT AND DISPATCH AND DECIDED TO RETURN TO ZZZ. ACCOMPLISHED THE IRREGULAR CHKLISTS FOR FLAP ASYMMETRY AND FLAP DISAGREE; DECLARED AN EMER AND LANDED WITHOUT INCIDENT WITH FLAPS 20 DEGS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR BELIEVES THAT ALL THE INDICATIONS CAN BE EXPLAINED BY A FAULTY MICRO-SWITCH THAT SENSES THE LEADING EDGE FLAPS ARE FULLY RETRACTED. LEADING EDGE FLAP POS SENSED BY THIS MICRO-SWITCH IS WHAT DETERMINES WHEN THE ENG IGNITERS ARE AUTOMATICALLY ACTIVATED AND THE RELAY THAT CTLS THE IGNITERS WHICH IS IN THE OVERHEAD; WAS RAPIDLY OPENING AND CLOSING MAKING A SOUND. ONCE ON THE GND THE LEADING EDGE FLAPS OPERATED NORMALLY ALTHOUGH THE INDICATION WAS STILL ERRATIC.