As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYSTEM - F/O ALTIMETER IN ERROR, IT READS 33850. CAPT ALTIMETER READS 34000. STBY ALT READS 34300, SELECTING ALTN AIR DATA CORRECTS FAULT. REPLACED RT ADC. OPS CHECK OK PER MM 34-12-01. PERFORMED MCDP TEST 30 TO RETAIN A/C LMP STATUS IN LAND 3. TEST 30 PASSED.