What was found
WHILE HAND FLYING AN RNAV APPROACH, GA MODE APPEARED ABOVE ENGINE DISPLAY WITHOUT COMMANDING GO-AROUND. VNAV PATH RECALIBRATED TO INDICATE AIRCRAFT 1000 FEET BELOW PATH. AIRCRAFT WAS VISUALLY ON PROPER GLIDE PATH. GROUNDED - YES. NO FAULTS LOGGED IN FMC'S OR DFCS REF B737-800 FIM 34-61 TASK 801 & 22-11 TASK 801. NO RELATED HGS FLIGHT FAULTS. HGS SYS TEST GOOD REF SMM 34-36-00. NO ADIRU FLIGHT FAULTS. L/R ADIRU OPS NML REF B737-800 AMM 34-21-00. NO CDS FLIGHT FAULTS. L/R DEU OPS NML REF AMM 34-62-00. NO A/T FLIGHT FAULTS. A/T OPS NML REF AMM 22-31-00. TOGA SWITCH DISCRETES GOOD. FMC L/R "FIXED OUTPUTS" GOOD. THRUST MODE ANNUN DISPLAY NML DURING TEST. A/P FLIGHT DIRECTOR GRP 12 GOOD - NO FAULTS. BITE LIBRARY 60.00 A/T, 60.18 FMC, 60.61 ALT ALERT GOOD. PERF LAND VERIFY TEST REF AMM 22-11-00. PASS-NO FAULTS. ETOPS GND VERIFICATION TEST SUCCESSFUL.