Narrative:

I was performing an overnight service check on a B757-200. One item on the job card required me to open each entry door; remove and clean any debris from the door sill/girt area. I found both doors 4-Left and 4-Right were in the unlatched position; the doors were left ajar; that is they were not fully closed. When I approached door 4-Left; I opened the door slowly to verify that the girt bar was not engaged; but after moving the door approximately one inch; the (door) assist bottle discharged and the door slide deployed. Only a slight movement of the door was all that was required to deploy the slide. Also; it appeared that the slide arm/disarm lever was left in the 'armed' position. While I make a habit of checking this lever before opening the door; apparently I overlooked it this time. As for what I can do in the future to avoid a similar incident; the obvious answer is to be more aware of the slide lever. In this incident; I may have been distracted by the unusual position of the door. Also; I believe that had there been an item on the service check job card to specifically verify that all doors have been disarmed; this would have increased my focus.

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Original NASA ASRS Text

Title: A Line Mechanic reports finding aft cabin doors 4-Left and 4-Right slightly ajar; not fully closed during an overnight service check on a B757-200. He attempted to verify the slide girt bar was not engaged by opening door 4-Left slowly to insure that the girt bar was not engaged; but the door assist bottle discharged and the slide deployed.

Narrative: I was performing an overnight service check on a B757-200. One item on the job card required me to open each entry door; remove and clean any debris from the door sill/girt area. I found both doors 4-Left and 4-Right were in the unlatched position; the doors were left ajar; that is they were not fully closed. When I approached door 4-Left; I opened the door slowly to verify that the girt bar was not engaged; but after moving the door approximately one inch; the (door) assist bottle discharged and the door slide deployed. Only a slight movement of the door was all that was required to deploy the slide. Also; it appeared that the slide arm/disarm lever was left in the 'armed' position. While I make a habit of checking this lever before opening the door; apparently I overlooked it this time. As for what I can do in the future to avoid a similar incident; the obvious answer is to be more aware of the slide lever. In this incident; I may have been distracted by the unusual position of the door. Also; I believe that had there been an item on the Service Check Job Card to specifically verify that all doors have been disarmed; this would have increased my focus.

Data retrieved from NASA's ASRS site as of April 2012 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.