AN MD10-10 COCKPIT DOOR WOULD NOT UNLOCK NORMALLY TO ALLOW CAPT TO RETURN TO THE COCKPIT. FO UNMASKED AND UNSTRAPPED; THEN GOT OUT OF SEAT TO MANUALLY OPEN THE DOOR.

Narrative

CAPT LEFT THE FLT DECK FOR LAVATORY. UPON RETURN; SIGNALED THE FO WITH STANDARD 'CODE' COMBINATION FOR COCKPIT RE-ENTRY. FO PLACED THE MAGNETIC DOOR CTL SWITCH TO THE UN-LOCKED POSITION. GREEN 'ENTRY' LIGHT ILLUMINATED ON KEYPAD IN SUPERNUMERARY AREA; BUT CAPT WAS UNABLE TO OPEN THE DOOR. AFTER SEVERAL SECONDS; CAPT AGAIN SIGNALED THE FO FOR RE-ENTRY. FO AGAIN ROTATED THE MAGNETIC DOOR LOCK CTL TO UNLOCK; BUT THIS TIME NOTED A 'LOCK FAIL' LIGHT ILLUMINATE. FO HAD TO UNMASK AND UNSTRAP; BRIEFLY LEAVING HIS FLT STATION UNATTENDED TO MANUALLY OPEN THE COCKPIT DOOR FOR THE CAPT TO RETURN TO HIS STATION. LUCKILY THE FO DID NOT HAVE TO LEAVE THE COCKPIT FOR HIS OWN 'RELIEF' PURPOSES; OTHERWISE THE SIT MIGHT HAVE REPEATED ITSELF. AFTER FURTHER REVIEW BY MAINT; THEY FOUND THE STRIKER SOLENOID STUCK. THE SOLENOID ROLLER WAS DEGREASED AND DOOR TESTED OK. MEL REMOVED AND ACFT OK FOR SERVICE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR BELIEVES THE COCKPIT DOOR NEEDS AN ENGINEERING REVIEW AS EVERYTHING THAT CAN GO WRONG WILL GO WRONG. INADEQUATE DOOR KNOBS AND AS IN THIS INCIDENT MAINT FOUND THE STRIKER SOLENOID STUCK. STRIKER WAS DEGREASED AND CLEANED AND OPERATED OK. SAFETY IS BEING COMPROMISED WHEN THE SINGLE CREWMAN IN THE COCKPIT MUST REMOVE THE O2 MASK AND UNSTRAP THE HARNESS AND LEAVE THE SEAT TO MANUALLY OPEN THE DOOR. CALLBACK CONVERSATION WITH RPTR ACN 639745 REVEALED THE FOLLOWING INFO: THE RPTR STATED THE DOOR WAS UNLOCKED FROM THE COCKPIT TWICE AND ON THE SECOND ATTEMPT THE DOOR FAILED ELECTRICALLY. REMOVED OXYGEN MASK AND SEAT BELT. LEFT THE SEAT AND MANUALLY OPENED THE DOOR. THIS IS A SAFETY OF FLT PROB AND NEEDS A POSITIVE FIX. THE RPTR INDICATED THAT THIS WAS THE SECOND EVENT OF A COCKPIT DOOR FAILURE LOCKING OUT CREW MEMBERS WHILE IN FLT. THE RPTR REFLECTED THAT THE SUBJECT DOOR ALWAYS CHKS OK ON THE GND WHEN REQUIRED CHKS ARE PERFORMED.