What was found
AT 17000 MIDWAY BETWEEN MHR AND RNO INLEVEL FLIGHT L HYD QTY EICAS MSG ILLUMINATED. L HYD QTY READ APPROX .60 AND DECREASING. SHORTLY THERAFTER L HYD ENG PMP EICAS ILLUMINATED FOLLOWED BY L HYD SYS PRESS AND LH QTY OF APPROX .14. LH ENG HYDDEFECTIVE O-RING FOUND ON FLAP SLAP DEPRESSURIZATION MODULE ITEMS 169 PLUG AND 175 O-RING OF IPC 29-51-29-01. NEW O-RING INSTALLED PER 20-10-19. NO LEAKS NOTED., VERIFIED VIA CREW AND AMC, PUMP IS WITHIN THE LIMITS OF 29-11-05 " NO EDP MAINT NECESSARY"