As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 1071 - EN ROUTE MKE-CWA - THE CAPTAINS ALTIMETER FLAGGED AND ALERTER WENT BLANK. AFTER TALKING WITH MAINTENANCE AND OPERATIONS THE DECISION WAS MADE TO RETURN TO MKE WHERE MAINTENANCE COULD WORK THE PROBLEM. MAINTENANCE REPLACED THE CAPTAINS ALTIMETER. MAINTENANCE OPS CHECKED THE ALTIMETER AND LEAK CHECKED THE PITOT AND STATIC SYSTEM AND RETURNED THE A/C TO SERVICE. (M)