As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU INFLIGHT START AT FL 410, OAT -60 WAS UNSUCCESSFULL AFTER 3 ATTEMPTS. REMOVED AND REPLACED THE APU IGNITION EXCITER IAW AMM 49-41-38. OPS CHECKED OK. VERIFICATION FLIGHT FOR APU COMPLETED. APU OPERATES NORMALLY. VERIFICATION OF COLD SOAK START VERIFIED BY MAINTENANCE.