Narrative:

During a trip to lavatory (cruise phase) I discovered that the arm/disarm switch on the main cargo door (mcd) control panel was unguarded and in the arm position. I observed the rest of the panel -- all lights were extinguished and I did not observe anything else wrong. I decided not to touch anything and notified the captain. Upon his subsequent inspection; he confirmed my observation and added that the hydraulic power switch was also in the 'on' position. Prior to departure; I had performed the lamp test of the panel in accordance with my preflight duties; while the mcd was still open. I noted no abnormalities at that time. The captain had performed the inspection of the mcd after it was closed and prior to closure of the L1 door. After assuring ourselves that it was safe to do so; we corrected the switch position and continued the flight normally. Our freighter procedures are currently in the form of a bulletin modified by a bulletin; which is extremely cumbersome; confusing; and rife with opportunities for error. It is on page 5 of bulletin X which modifies bulletin Y; that the instructions for pre-departure inspection of the main cargo door (mcd) appear. They are presented as a modification of the original bulletin's preliminary interior inspection -- which is normally performed by the first officer at a time when the mcd is rarely closed. So; perhaps we should delay the preliminary inspection until the mcd is closed? Furthermore the said procedure states; 'verify that all switches are off.' I suggest that something like 'and the arm/disarm switch is in the disarm position and guarded' be added. (And that this and all freighter procedures be incorporated into the flight handbook in user-friendly format as soon as possible!) additionally; the loading crews should be reminded that the mcd is not 'safed' until the mcd control panel is in the proper confign for flight. Callback conversation with reporter revealed the following information: the reporter stated that only cargo personnel operate the door; and after loading is complete; the flight crew is to check the exterior door latch indicators and also verify that the door disarm switch is in the guarded 'disarm' position. Door activation is also deactivated by a landing gear safety switch which will not allow door activation in flight. Reporter also stated that the procedures for preflight inspection of the door are not clearly defined in the flight handbook.

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Original NASA ASRS Text

Title: SWITCHES FOR DOOR OPERATION OF A B737 FREIGHT ACFT WERE DISCOVERED TO BE IN THE ARMED POSITION DURING FLT.

Narrative: DURING A TRIP TO LAVATORY (CRUISE PHASE) I DISCOVERED THAT THE ARM/DISARM SWITCH ON THE MAIN CARGO DOOR (MCD) CTL PANEL WAS UNGUARDED AND IN THE ARM POS. I OBSERVED THE REST OF THE PANEL -- ALL LIGHTS WERE EXTINGUISHED AND I DID NOT OBSERVE ANYTHING ELSE WRONG. I DECIDED NOT TO TOUCH ANYTHING AND NOTIFIED THE CAPT. UPON HIS SUBSEQUENT INSPECTION; HE CONFIRMED MY OBSERVATION AND ADDED THAT THE HYD PWR SWITCH WAS ALSO IN THE 'ON' POS. PRIOR TO DEP; I HAD PERFORMED THE LAMP TEST OF THE PANEL IN ACCORDANCE WITH MY PREFLT DUTIES; WHILE THE MCD WAS STILL OPEN. I NOTED NO ABNORMALITIES AT THAT TIME. THE CAPT HAD PERFORMED THE INSPECTION OF THE MCD AFTER IT WAS CLOSED AND PRIOR TO CLOSURE OF THE L1 DOOR. AFTER ASSURING OURSELVES THAT IT WAS SAFE TO DO SO; WE CORRECTED THE SWITCH POS AND CONTINUED THE FLT NORMALLY. OUR FREIGHTER PROCS ARE CURRENTLY IN THE FORM OF A BULLETIN MODIFIED BY A BULLETIN; WHICH IS EXTREMELY CUMBERSOME; CONFUSING; AND RIFE WITH OPPORTUNITIES FOR ERROR. IT IS ON PAGE 5 OF BULLETIN X WHICH MODIFIES BULLETIN Y; THAT THE INSTRUCTIONS FOR PRE-DEP INSPECTION OF THE MAIN CARGO DOOR (MCD) APPEAR. THEY ARE PRESENTED AS A MODIFICATION OF THE ORIGINAL BULLETIN'S PRELIMINARY INTERIOR INSPECTION -- WHICH IS NORMALLY PERFORMED BY THE FO AT A TIME WHEN THE MCD IS RARELY CLOSED. SO; PERHAPS WE SHOULD DELAY THE PRELIMINARY INSPECTION UNTIL THE MCD IS CLOSED? FURTHERMORE THE SAID PROC STATES; 'VERIFY THAT ALL SWITCHES ARE OFF.' I SUGGEST THAT SOMETHING LIKE 'AND THE ARM/DISARM SWITCH IS IN THE DISARM POS AND GUARDED' BE ADDED. (AND THAT THIS AND ALL FREIGHTER PROCS BE INCORPORATED INTO THE FLT HANDBOOK IN USER-FRIENDLY FORMAT ASAP!) ADDITIONALLY; THE LOADING CREWS SHOULD BE REMINDED THAT THE MCD IS NOT 'SAFED' UNTIL THE MCD CTL PANEL IS IN THE PROPER CONFIGN FOR FLT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT ONLY CARGO PERSONNEL OPERATE THE DOOR; AND AFTER LOADING IS COMPLETE; THE FLT CREW IS TO CHECK THE EXTERIOR DOOR LATCH INDICATORS AND ALSO VERIFY THAT THE DOOR DISARM SWITCH IS IN THE GUARDED 'DISARM' POSITION. DOOR ACTIVATION IS ALSO DEACTIVATED BY A LNDG GEAR SAFETY SWITCH WHICH WILL NOT ALLOW DOOR ACTIVATION IN FLT. REPORTER ALSO STATED THAT THE PROCEDURES FOR PREFLIGHT INSPECTION OF THE DOOR ARE NOT CLEARLY DEFINED IN THE FLT HANDBOOK.

Data retrieved from NASA's ASRS site as of January 2009 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.