Narrative:

The B737 has several red guarded switches including 2 covering the idg disconnect switches. These switches are not safety wired, and confusion has resulted in several incidents where the passenger oxygen masks were inadvertently deployed when crews attempted to test the DFDR. In my case, the #2 engine idg was disconnected when I meant to turn off the emergency exit lights per the checklist. This is a major safety breakdown in design, and until the covers are safety wired, we will continue to have these problems.

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Original NASA ASRS Text

Title: RPTR ADVISES THAT COMPANY FAILURE TO REQUIRE SAFETY WIRING OF CRITICAL RED CAPPED SYS OPERATING SWITCHES RESULTS IN INADVERTENT OP OF THOSE SWITCHES, SOME OF WHICH RESULT IN NON-CORRECTABLE RESULTS, IE, GENERATOR DISCONNECT SWITCHES.

Narrative: THE B737 HAS SEVERAL RED GUARDED SWITCHES INCLUDING 2 COVERING THE IDG DISCONNECT SWITCHES. THESE SWITCHES ARE NOT SAFETY WIRED, AND CONFUSION HAS RESULTED IN SEVERAL INCIDENTS WHERE THE PAX OXYGEN MASKS WERE INADVERTENTLY DEPLOYED WHEN CREWS ATTEMPTED TO TEST THE DFDR. IN MY CASE, THE #2 ENG IDG WAS DISCONNECTED WHEN I MEANT TO TURN OFF THE EMER EXIT LIGHTS PER THE CHKLIST. THIS IS A MAJOR SAFETY BREAKDOWN IN DESIGN, AND UNTIL THE COVERS ARE SAFETY WIRED, WE WILL CONTINUE TO HAVE THESE PROBS.

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.