As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO PERFORM NORMAL GEAR EXTENSION. ACCOMPLISHED MISSED APPROACH AND PERFORMED ALTERNATE EXTENSION PROCEDURE. *S/D* NOSE GEAR DOOR SEQUENCE VALVE HAD DETERIORATED O RING AND BACKUP RING REQUIRING LONGER THAN NORMAL THROW OF THE SPOOL VALVE. REPLACED DOOR SEQUENCE VALVE. (ORIGINAL VALVE).