What was found
CLIMBING THROUGH 20,000 MSL STANDBY ALTIMETER INDICATED AN ALTITUDE THAT WAS 10,000 HIGHER THAN THE ACTUAL ALTITUDE AS INDICATED ON THE CAPTAIN'S AND F/O'S ALTIMETERS. REMAINED IN ERROR THROUGHOUT THE FLIGHT. UPON ARRIVAL FOUND STANDBY ALTIMETER INDICATING 10,000 FEET ABOVE FIELD ELEVATION. R & R STANDBY ALTIMETER IAW AMM 34-12-024-4. ACCOMPLISHED LOW LEVEL PITOT STATIC TEST IAW AMM 34-11-000-5. OPS TEST OK. ACFT OK FOR SERVICE. PREMATURE REMOVAL/INSTALLATION OFF. FINAL CLOSED.