As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - RT DUCT PRESS SURGES TO 40 PSI FROM 20 PSI. LT DUCT PRESS STEADY AT 20 PSE, THEN RT DUCT PRESSURE REMAINED AT 40 PSI-CRUSE PWR 86 PERCENT N1. REMOVED AND REPLACED NR1 ENGINE PRSOV IAW AMM 36-11-09. ACCOMPLISHED HIGH POWER ENG RUN ON LT ENGINE IAW AMM TASK 71-00-00-802-063. OPS NORMAL.