Narrative:

Arriving at aircraft; I notice gpu was plugged in and running and main cabin door was closed. Upon opening door and entering aircraft noticed the aircraft cabin air temperature was very hot; 35 degrees C. The flight deck air temperature was very hot; hotter than cabin's temperature. The flight deck's external AC switch was selected on with the battery master switch in the off position; not the proper procedure for accepting ground power. With no battery on; stray electrical surges are not absorbed and may cause problems with the relays. The recirculation fan was on as normal. I brought the aircraft in the night before and performed parking and terminating checklist; the aircraft was dark when we secured the plane. The center console in the flight deck was extremely hot to the touch (skin burn possible). I turned the battery master on and then performed a terminating checklist to shut aircraft down properly to reset relays. After numerous unanswered calls to operations I finally notified operations to hold boarding in order to make sure aircraft was acceptable for passengers and to have ramp supervisor report to me. I performed flight compartment safety check list and repowered aircraft. I started APU for cooling. I called maintenance control to discuss issue about the hot avionics. We agreed that all the relays properly set and the temperatures were cooling ok; a maintenance discrepancy was not warranted. The only concern would be CRT overheating that would correct itself. With no cooling air the avionics heat up and the recirculation fan heats up the cabin. I believe without the battery master on; the avionics exhaust ground valve may not have been open to dump the hot air adding to the overheating. I informed the night shift supervisor that the flight deck external AC switch is not to be used by ramp crew/cleaning crew for cabin lighting and showed him the AC service switch located in the communication panel on the right side of the nose. I asked him to spread the word and make a memo. Passengers were boarded a short while later as the temperatures decreased and we departed with no further issues. I believe this problem could cause damage to aircraft and may cause someone to be burned. This station handles boeing and mcdonald douglas equipment that does not require the battery master to be selected on while accepting ground power. This may have led the overnight ground crew to select the flight deck's external AC switch without turning the battery master on. A strongly worded memo to all ground stations about external AC service switch and some training review on gpu usage is in order to prevent any further issues and possible damage to aircraft.

Related reports:

Google
 

Original NASA ASRS Text

Title: A CRJ 700 Captain reports discovering aircraft powered with battery switch off and the cockpit very hot. The center pedestal was too hot to touch due to avionics cooling being inoperative with battery switch off.

Narrative: Arriving at aircraft; I notice GPU was plugged in and running and main cabin door was closed. Upon opening door and entering aircraft noticed the aircraft cabin air temperature was very hot; 35 degrees C. The flight deck air temperature was very hot; hotter than cabin's temperature. The flight deck's external AC switch was selected on with the battery master switch in the off position; not the proper procedure for accepting ground power. With no battery on; stray electrical surges are not absorbed and may cause problems with the relays. The recirculation fan was on as normal. I brought the aircraft in the night before and performed parking and terminating checklist; the aircraft was dark when we secured the plane. The center console in the flight deck was extremely hot to the touch (skin burn possible). I turned the battery master on and then performed a terminating checklist to shut aircraft down properly to reset relays. After numerous unanswered calls to operations I finally notified operations to hold boarding in order to make sure aircraft was acceptable for passengers and to have ramp supervisor report to me. I performed flight compartment safety check list and repowered aircraft. I started APU for cooling. I called Maintenance Control to discuss issue about the hot avionics. We agreed that all the relays properly set and the temperatures were cooling ok; a maintenance discrepancy was not warranted. The only concern would be CRT overheating that would correct itself. With no cooling air the avionics heat up and the recirculation fan heats up the cabin. I believe without the battery master on; the avionics exhaust ground valve may not have been open to dump the hot air adding to the overheating. I informed the night shift supervisor that the flight deck external AC switch is not to be used by ramp crew/cleaning crew for cabin lighting and showed him the AC service switch located in the communication panel on the right side of the nose. I asked him to spread the word and make a memo. Passengers were boarded a short while later as the temperatures decreased and we departed with no further issues. I believe this problem could cause damage to aircraft and may cause someone to be burned. This station handles Boeing and McDonald Douglas equipment that does not require the battery master to be selected on while accepting ground power. This may have led the overnight ground crew to select the flight deck's external AC switch without turning the battery master on. A strongly worded memo to all ground stations about external AC service switch and some training review on GPU usage is in order to prevent any further issues and possible damage to aircraft.

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.