Narrative:

After a routing night landing at isp, a red level 3 warning of a #1 battery overheat was annunciated, with the accompanying triple chime. The captain was taxiing the aircraft. The emergency checklist procedure calls for turning off the respective battery charger, followed by the statement, 'land as soon as practicable.' the captain reached up to turn off the #1 battery charger switch, which was illuminated with a 'fault' light. Most of the overhead panel switches, including those for the battery chargers, are of the 'push on--push off' type. The #1 battery charger switch was stuck in the 'on' position, at the bottom of its travel, buried in the overhead panel. The captain then turned off the main battery switch, which is a large toggle type, and directed me to do what I could to get the battery charger switch off. I had to unbelt myself and semi-stand to get good access, and after no luck hammering on the panel with my knuckles, the captain said, 'have you got a pocket knife?' by chance, I did--the first time I ever carried one while flying! After a minute or so of digging, it popped out into the 'off' position, but the overheat warning persisted. Within about 2 mins or less, the warning extinguished and we were at the gate. This type of switch is inadequate for controling systems which must be turned off or on as part of an emergency procedure, if they are going to be intermittently stuck. I've seen others stick on, such as fuel pumps and pitot heat, but these were nuisance items. The main battery switch, which is a large toggle-type, doesn't disconnect the batteries from the chargers, but perhaps it should, if the regular switches are stuck sometimes. You shouldn't have to get out of your seat and use tools to operate a normal switch--especially while performing an emergency checklist. There are many other critical systems controled by these same types of switches. There either has to be a maintenance function to be sure that they work, or the pilots will have to start cycling them all before the first flight of the day.

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Original NASA ASRS Text

Title: NIGHT LNDG AT ISP, TAXIING IN A BATTERY OVERHEAT WAS NOTED. DIFFICULTY IN FORCING ISOLATION SWITCH FOR THAT BATTERY TO MOVE TO OFF POSITION.

Narrative: AFTER A ROUTING NIGHT LNDG AT ISP, A RED LEVEL 3 WARNING OF A #1 BATTERY OVERHEAT WAS ANNUNCIATED, WITH THE ACCOMPANYING TRIPLE CHIME. THE CAPT WAS TAXIING THE ACFT. THE EMER CHKLIST PROC CALLS FOR TURNING OFF THE RESPECTIVE BATTERY CHARGER, FOLLOWED BY THE STATEMENT, 'LAND AS SOON AS PRACTICABLE.' THE CAPT REACHED UP TO TURN OFF THE #1 BATTERY CHARGER SWITCH, WHICH WAS ILLUMINATED WITH A 'FAULT' LIGHT. MOST OF THE OVERHEAD PANEL SWITCHES, INCLUDING THOSE FOR THE BATTERY CHARGERS, ARE OF THE 'PUSH ON--PUSH OFF' TYPE. THE #1 BATTERY CHARGER SWITCH WAS STUCK IN THE 'ON' POS, AT THE BOTTOM OF ITS TRAVEL, BURIED IN THE OVERHEAD PANEL. THE CAPT THEN TURNED OFF THE MAIN BATTERY SWITCH, WHICH IS A LARGE TOGGLE TYPE, AND DIRECTED ME TO DO WHAT I COULD TO GET THE BATTERY CHARGER SWITCH OFF. I HAD TO UNBELT MYSELF AND SEMI-STAND TO GET GOOD ACCESS, AND AFTER NO LUCK HAMMERING ON THE PANEL WITH MY KNUCKLES, THE CAPT SAID, 'HAVE YOU GOT A POCKET KNIFE?' BY CHANCE, I DID--THE FIRST TIME I EVER CARRIED ONE WHILE FLYING! AFTER A MINUTE OR SO OF DIGGING, IT POPPED OUT INTO THE 'OFF' POS, BUT THE OVERHEAT WARNING PERSISTED. WITHIN ABOUT 2 MINS OR LESS, THE WARNING EXTINGUISHED AND WE WERE AT THE GATE. THIS TYPE OF SWITCH IS INADEQUATE FOR CTLING SYSTEMS WHICH MUST BE TURNED OFF OR ON AS PART OF AN EMER PROC, IF THEY ARE GOING TO BE INTERMITTENTLY STUCK. I'VE SEEN OTHERS STICK ON, SUCH AS FUEL PUMPS AND PITOT HEAT, BUT THESE WERE NUISANCE ITEMS. THE MAIN BATTERY SWITCH, WHICH IS A LARGE TOGGLE-TYPE, DOESN'T DISCONNECT THE BATTERIES FROM THE CHARGERS, BUT PERHAPS IT SHOULD, IF THE REGULAR SWITCHES ARE STUCK SOMETIMES. YOU SHOULDN'T HAVE TO GET OUT OF YOUR SEAT AND USE TOOLS TO OPERATE A NORMAL SWITCH--ESPECIALLY WHILE PERFORMING AN EMER CHKLIST. THERE ARE MANY OTHER CRITICAL SYSTEMS CTLED BY THESE SAME TYPES OF SWITCHES. THERE EITHER HAS TO BE A MAINT FUNCTION TO BE SURE THAT THEY WORK, OR THE PLTS WILL HAVE TO START CYCLING THEM ALL BEFORE THE FIRST FLT OF THE DAY.

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.