What was found
ON FLT 157 - ATL-MSY - AIR RETURN, ON CLIMB-OUT BOTH MASTER CAUTION LIGHTS CAME ON INTERMITTENTLY, (FLICKERED DIMLY), NO OTHER INDICATION, ANNUNCIATOR LIGHTS TESTED NORMAL. FOUND WIRE NR E204A18 CHAFED TO NR 1 ENGINE CASE, REPAIRED WIRE PER DC MM 20 STANDARD WIRING PRACTICE, OPS CHECK GOOD PER DC MM 79-33. (M)