Narrative:

The first officer and I were accomplishing our final preparations for pushback when the first flight attendant came into the cockpit and advised us that a gate agent wanted to open the 1L door (the door was closed for departure) for some unknown reason. The flight attendant advised me that she was not allowed to open the door once it has been closed. Why the gate agent didn't open the door herself is unknown. I advised the flight attendant that I would come back and open the door. As I was leaving the cockpit; I forewarned everyone that we had to make sure the doors are unarmed. Upon entering the galley area; I visually checked to my left that the 1R door; slide was clearly disarmed (light illumination of that area was adequate for visual inspection). The forward area near the 1L door was dimly illuminated when I approach the door. I pointed to the arm lever to verify the unarmed position. The first flight attendant was standing next to me and was observing my actions. When I said; while pointing to the arm handle; door unarmed? I heard the word 'ok' thus; having a second confirmation for an unarmed condition before opening the 1L door. Thinking the lever was in the unarmed position; I continued to lift the door handle (I could not see the labeling for armed/disarmed because of the dim lights). In haste of opening the door; I failed to observe the girt bar engagement slide armed light illumination. The door opened slowly; I could faintly hear the sound of the compressed air from the door assist bottle. The door did not fly open as in training classes. Initially; it felt like the door was being opened by the gate agent. The 1L slide proceeded to fall from the door bustle to the jetway floor. The slide did not inflate. At that point; I cleared everyone away for the slide and contacted dispatch. Why the slide lever of 1L slide was not in the unarmed position in the first place when door 1R arm lever was in the unarmed position is unknown. Passengers were removed from the aircraft to the waiting area approximately 25 minutes after the partial deployment of the slide. I communicated to the passengers every 10 minutes and was in constant communications with the dispatcher and maintenance control. The crew was fully informed to the course of events and actions. Flight departed several hours later. En route; we encountered several more non-normal situations. We were alerted to a medical emergency with a passenger and we experienced a forward lavatory smoke alarm. The paramedics were called and met the aircraft/passenger at the gate upon arrival. The smoke alarm was a false warning due to a passenger using hairspray in the lavatory. I believe there are several variable factors that contributed to this incident (as in any incident or accident). The failure of the flight attendant to disarmed the door before leaving her area. Imperfect communications between myself and the first flight attendant with regards on how we are going to open the door in this non-normal situation [and] inadequate illumination of the door entrance area (which could have been easily corrected). My shortfall to noticed the door was actually armed (this may have been cause my over contemplation or haste to assure that the doors were disarmed....couldn't see the forest for all the trees). [Also] I omitted to follow company procedures in having the first officer come back to verify the arm lever position. Gate agent failure to open the door from the outside (thus preventing the door slide from activation in the first place); the departure tension for that 'on time' departure. The very nature of late night flights and the effects of possible mild chronic fatigue on crew members after repeated night flight assignments should not be disregarded. All of these factors occurring at the precise moment enhanced the diversions of the crew. My analysis of the event; the influence of poor illumination of the door area and poor visual confirmation of the lever position by the crew was the major factor why the slide was deployed. If the entrance light were at full bright; we would have seen the lever was not in the proper position for door opening.

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Original NASA ASRS Text

Title: B757 Captain describes an inadvertent slide deployment that he was directly involved with.

Narrative: The First Officer and I were accomplishing our final preparations for pushback when the first Flight Attendant came into the cockpit and advised us that a gate agent wanted to open the 1L door (the door was closed for departure) for some unknown reason. The Flight Attendant advised me that she was not allowed to open the door once it has been closed. Why the gate agent didn't open the door herself is unknown. I advised the Flight Attendant that I would come back and open the door. As I was leaving the cockpit; I forewarned everyone that we had to make sure the doors are unarmed. Upon entering the galley area; I visually checked to my left that the 1R door; slide was clearly disarmed (light illumination of that area was adequate for visual inspection). The forward area near the 1L door was dimly illuminated when I approach the door. I pointed to the arm lever to verify the unarmed position. The first Flight Attendant was standing next to me and was observing my actions. When I said; while pointing to the arm handle; door unarmed? I heard the word 'OK' thus; having a second confirmation for an unarmed condition before opening the 1L door. Thinking the lever was in the unarmed position; I continued to lift the door handle (I could not see the labeling for armed/disarmed because of the dim lights). In haste of opening the door; I failed to observe the Girt Bar Engagement Slide Armed Light illumination. The door opened slowly; I could faintly hear the sound of the compressed air from the door assist bottle. The door did not fly open as in training classes. Initially; it felt like the door was being opened by the gate agent. The 1L slide proceeded to fall from the door bustle to the jetway floor. The slide did not inflate. At that point; I cleared everyone away for the slide and contacted Dispatch. Why the slide lever of 1L slide was NOT in the unarmed position in the first place when door 1R arm lever was in the unarmed position is unknown. Passengers were removed from the aircraft to the waiting area approximately 25 minutes after the partial deployment of the slide. I communicated to the passengers every 10 minutes and was in constant communications with the Dispatcher and Maintenance Control. The crew was fully informed to the course of events and actions. Flight departed several hours later. En route; we encountered several more non-normal situations. We were alerted to a medical emergency with a passenger and we experienced a forward lavatory smoke alarm. The paramedics were called and met the aircraft/passenger at the gate upon arrival. The smoke alarm was a false warning due to a passenger using hairspray in the lavatory. I believe there are several variable factors that contributed to this incident (as in any incident or accident). The failure of the Flight Attendant to disarmed the door before leaving her area. Imperfect communications between myself and the first Flight Attendant with regards on how we are going to open the door in this non-normal situation [and] inadequate illumination of the door entrance area (which could have been easily corrected). My shortfall to noticed the door was actually armed (this may have been cause my over contemplation or haste to assure that the doors were disarmed....couldn't see the forest for all the trees). [Also] I omitted to follow company procedures in having the First Officer come back to verify the arm lever position. Gate agent failure to open the door from the outside (thus preventing the door slide from activation in the first place); the departure tension for that 'on time' departure. The very nature of late night flights and the effects of possible mild chronic fatigue on crew members after repeated night flight assignments should not be disregarded. All of these factors occurring at the precise moment enhanced the diversions of the crew. My analysis of the event; the influence of poor illumination of the door area and poor visual confirmation of the lever position by the crew was the major factor why the slide was deployed. If the entrance light were at full bright; we would have seen the lever was not in the proper position for door opening.

Data retrieved from NASA's ASRS site as of July 2013 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.