As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYSTEM, AT CRUISE ALTITUDE FIRST OFFICER'S ALTIMETER IS 200' TOO LOW AT FL 340 ALT 34,300 CAPT =34,000 FO=33,800. IT CORRECT WHEN SELECTING ALT AIR DATA. REMOVED AND REPLACED LT ADC PER AMM 34-12-01. OPS CK OK. PERFORMED TEST 30 PASS ALL TEST. A/C REMAINS IN LAND 3 STATUS.