As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON A ROUTINE FLIGHT, THE PILOT NOTED THAT THROUGH ROTATION THE NR 1 ALTIMETER FAILED IN THE CLIMBOUT. THE CREW DID NOT REALIZE THAT THERE WAS A SWITCH LOCATED IN THE COCKPIT TO SELECT WITCH ENCODING ALTIMETER THAT PROVIDES THE MODE C. THEREFORE THE ACFT ENTERED CLASS C AIRSPACE WITHOUT A FUNCTIONING MODE C. MAINTENANCE REPLACED THE ALTIMETER A FUNCTION CHECKED THE SYS SERVICEABLE.