As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PER AD20201651-NG-36-1 NR 1 ENGINE 5TH STAGE BLEED AIR CHECK VALVE FAILED GAP CHECK. REMOVED 5TH STAGE BLEED AIR CHECK VALVE NR 1 ENGINE, PER AD20201651-NG-36-1. GROUNDED-YES. R&R NR 1 ENGINE 5TH STAGE BLEED AIR VALVE, REF B737-800 AMM 36-11-02. OPERATIONS AND LEAK CHECK GOOD. ACCOMPLISHED AD 20201651-NG-36-1.