What was found
DURING CLIMB, REPORTED RECEIVING AN ECAM MESSAGE FOR " ENG1 BEARING 4 OIL SYS - HI PRESS". RETURNED & LANDED WITHOUT FURTHER EVENT. MX R & R NR 4 BEARING SCAVENGE VALVE ON NR 1 ENG IAW MM 79-23-51. COMPLIED WITH HIGH POWER ASSURANCE TEST IAW AWA TC F5M71312. OPS TESTS GOOD. TEARDOWN REPORT CONFIRMS FAILURE. UNITS INTERNAL PISTON MOVED BETWEEN HIGH POWER & LOWER POWER POSITIONS BUT REED SWITCH DID NOT FUNCTION WHEN UNIT OPERATED, NOT INDICATING TRUE POSITION OF PISTON. REMOVAL OF REED SWITCH FOUND GLASS FERRULE TUBE ENCASING SWITCH ASSY FRACTURED, FAILURE OF REED SWITCH WOULD HAVE CAUSED THE REPORTED MESSAGES. UNIT INSPECTED, REPAIRED, TESTED & RETURNED TO SERVICE IAW CMM 79-25-41.