What was found
ORD - FLT 4259 - DURING CLIMB THROUGH 280 KNOTS, 11,000 FT, LOST MAIN PITCH TRIM, STANDBY WAS WORKING. EICAS MESSAGE `PTRIM MAIN INOP` PERFORMED EMERGENCY CHECKLIST. MAIN PITCH TRIM INOPERATIVE. BACK TRIM FAIL TO TRIM UP. NO EICAS MESSAGE. CONTINUE CHECKLIST WITH DUAL PITCH TRIM FAILURE. RESET CIRCUIT BREAKER E-11, C-24, REGAINED MAIN PITCH TRIM. REMOVED AND REPLACED STANDBY PITCH TRIM PANEL AND HSCU P/N 362100101013, S/N 4613. OPERATIONAL CHECK GOOD. AIRCRAFT PASSED FUNCTIONAL CHECK FLIGHT. RETURNED AIRCRAFT TO SERVICE. (M)