Narrative:

The frequency being used was HF. I couldn't get the company report page to take any HF frequency no matter how I entered it, so I put 121.5 in since I was monitoring it during the overwater/HF portion of the flight. Our exact localizer at the time of the incident was about 100 NM south of champ. During cruise, I called the flight attendants about a lav break. They ensured the fwd lav was empty, the cart was across the aisle, and that more than one flight attendant was present (there were three). They then called me, informed me the area was clear, and I confirmed it through the view port. I opened the door, handed them the meal trays, closed the cockpit door behind me as the flight attendant was asking if I wanted her to go into the cockpit? I said yes as I realized what I had done. I quickly used the lav and then informed the first officer, via the interphone, that I had mistakenly closed the door (he had obviously already realized that), and I was going to use the code to open the cockpit door. I retained communication with him until the door timed open, then I reentered the cockpit and resecured the door. The flight attendants then moved the cart and left the galley area. There is a possible security problem when only one pilot is in the cockpit. Had three flight attendants not been in the galley area, the cart not been across the aisle, and the interphone not been used to coordinate the code opening of the door, there was the potential of a cockpit breach, had one been planned. These measures lessened that possibility during what, I hope, is the only time this ever happens to me or my crew.

Google
 

Original NASA ASRS Text

Title: A B757-200 CAPT, DURING A TRANSOCEANIC FLT, MISTAKENLY DID NOT FOLLOW THE PROPER SECURITY PROCS FOR LEAVING THE COCKPIT TO USE THE LAV.

Narrative: THE FREQUENCY BEING USED WAS HF. I COULDN'T GET THE COMPANY RPT PAGE TO TAKE ANY HF FREQUENCY NO MATTER HOW I ENTERED IT, SO I PUT 121.5 IN SINCE I WAS MONITORING IT DURING THE OVERWATER/HF PORTION OF THE FLT. OUR EXACT LOC AT THE TIME OF THE INCIDENT WAS ABOUT 100 NM S OF CHAMP. DURING CRUISE, I CALLED THE FLT ATTENDANTS ABOUT A LAV BREAK. THEY ENSURED THE FWD LAV WAS EMPTY, THE CART WAS ACROSS THE AISLE, AND THAT MORE THAN ONE FLT ATTENDANT WAS PRESENT (THERE WERE THREE). THEY THEN CALLED ME, INFORMED ME THE AREA WAS CLR, AND I CONFIRMED IT THROUGH THE VIEW PORT. I OPENED THE DOOR, HANDED THEM THE MEAL TRAYS, CLOSED THE COCKPIT DOOR BEHIND ME AS THE FLT ATTENDANT WAS ASKING IF I WANTED HER TO GO INTO THE COCKPIT? I SAID YES AS I REALIZED WHAT I HAD DONE. I QUICKLY USED THE LAV AND THEN INFORMED THE FO, VIA THE INTERPHONE, THAT I HAD MISTAKENLY CLOSED THE DOOR (HE HAD OBVIOUSLY ALREADY REALIZED THAT), AND I WAS GOING TO USE THE CODE TO OPEN THE COCKPIT DOOR. I RETAINED COM WITH HIM UNTIL THE DOOR TIMED OPEN, THEN I REENTERED THE COCKPIT AND RESECURED THE DOOR. THE FLT ATTENDANTS THEN MOVED THE CART AND LEFT THE GALLEY AREA. THERE IS A POSSIBLE SECURITY PROB WHEN ONLY ONE PLT IS IN THE COCKPIT. HAD THREE FLT ATTENDANTS NOT BEEN IN THE GALLEY AREA, THE CART NOT BEEN ACROSS THE AISLE, AND THE INTERPHONE NOT BEEN USED TO COORDINATE THE CODE OPENING OF THE DOOR, THERE WAS THE POTENTIAL OF A COCKPIT BREACH, HAD ONE BEEN PLANNED. THESE MEASURES LESSENED THAT POSSIBILITY DURING WHAT, I HOPE, IS THE ONLY TIME THIS EVER HAPPENS TO ME OR MY CREW.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.