As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER RUNNING-UP THE ENGINES BY MAINTENANCE ACAS, IT WAS NOTICED SOME SMOKE COMING FROM THE NR 1 ENGINE EXHAUST AFTER SHUTDOWN. INVESTIGATING LEAD TO CHECKING THE PURGE TANK AND VALVE SYS. UPON OPENING THE SIDE COWLING IT WAS FOUND THAT 1 END-CAP OF THE PURGE TANK HAD COMPLETELY COME OFF THE TANK, EXPOSING THE INSIDE OF THE TANK.