Narrative:

Pushed off gate X. Taxiing out; we had gotten a warn elex status message. Contacted maintenance and asked ground control for an area where we could stop to work with the maintenance issue at hand. We were on taxiway west short of south. Maintenance instructed us to go to the maintenance page and pull up air traffic area code 31 and push the clear/delete and erase the status message. The message was latched and would not clear. Maintenance had informed us that the battery had been changed in the aircraft and the system was asking for a system test that it was not able to perform. We were then told to return to the gate because they needed to reset the system and that we could not depart with the system in this condition. The captain made a PA informing the passengers that we were having to return to the gate for a maintenance issue. The [relief pilot] spoke to the purser informing him of the maintenance issue we were having and to let the rest of the flight attendants know we were returning to the gate for maintenance to clear the problem. We taxied south; Y; and held short of U as ramp was going to park us in the ball park to meet maintenance. Because of a 737 that was in the way; they instead sent us to [gate] Y. At [gate] Y awaited for ramp to park us. We were a surprise to the ramp personnel because it didn't seem like they were informed that we were coming in. After parking; the captain instructed the flight attendants to disarm the doors because maintenance would be coming on. Maintenance showed up shortly after. A mechanic got on the ground call and the captain talked to him through the inter phone. We tried to clear the message again and again it did not work. The mechanic on the inter phone told us they would need to come up. A short time later I heard a male scream from the back (as it turns out it was our flight attendant who had fallen through the open access hatch) and another mechanic was in the hatch area under the floor. At no time were we forewarned that a mechanic would enter through the floor electronics and equipment access hatch so that we could relay that to the flight attendants to remain clear of the hatch area and keep our passengers away. Again; we confirmed that the doors were disarmed thinking that they would enter through the forward entry door and waited for the jetway to move before the incident happened. After the incident; the captain had me call operations. I called operations and informed them of what had happened and requested paramedics and a flight attendant supervisor to come to the aircraft. The paramedics showed up as did port authority police. The port authority police were in the flight deck entry area talking to the captain and asking for his info and why there was no supervisor present. I called operations a few more times requesting a flight attendant supervisor and or any supervisor. I informed operations that the port authority [police] required a supervisor be there for this type of event. I was informed that the flight attendant and mechanic were both transported to the hospital to get checked. I remained in the flight deck throughout the incident relaying information to operations and monitoring the radios and performing duties I was given.

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Original NASA ASRS Text

Title: First Officer reported WARN ELEXEICAS Message on taxi; requiring resets and Maintenance to meet aircraft at remote without boarding stairs. Flight Attendant fell through the access panel to the Forward Avionics bay; landing on a mechanic; injuring them both.

Narrative: Pushed off Gate X. Taxiing out; we had gotten a WARN ELEX status message. Contacted Maintenance and asked Ground Control for an area where we could stop to work with the maintenance issue at hand. We were on Taxiway W short of S. Maintenance instructed us to go to the maintenance page and pull up ATA code 31 and push the Clear/Delete and erase the status message. The message was latched and would not clear. Maintenance had informed us that the battery had been changed in the aircraft and the system was asking for a system test that it was not able to perform. We were then told to return to the gate because they needed to reset the system and that we could not depart with the system in this condition. The Captain made a PA informing the passengers that we were having to return to the gate for a maintenance issue. The [Relief Pilot] spoke to the Purser informing him of the maintenance issue we were having and to let the rest of the flight attendants know we were returning to the gate for maintenance to clear the problem. We taxied S; Y; and held short of U as Ramp was going to park us in the ball park to meet Maintenance. Because of a 737 that was in the way; they instead sent us to [Gate] Y. At [Gate] Y awaited for Ramp to park us. We were a surprise to the ramp personnel because it didn't seem like they were informed that we were coming in. After parking; the Captain instructed the flight attendants to disarm the doors because Maintenance would be coming on. Maintenance showed up shortly after. A mechanic got on the ground call and the Captain talked to him through the inter phone. We tried to clear the message again and again it did not work. The mechanic on the inter phone told us they would need to come up. A short time later I heard a male scream from the back (as it turns out it was our flight attendant who had fallen through the open access hatch) and another mechanic was in the hatch area under the floor. At no time were we forewarned that a mechanic would enter through the floor Electronics and Equipment access hatch so that we could relay that to the flight attendants to remain clear of the hatch area and keep our passengers away. Again; we confirmed that the doors were disarmed thinking that they would enter through the forward entry door and waited for the jetway to move before the incident happened. After the incident; the Captain had me call Operations. I called Operations and informed them of what had happened and requested paramedics and a Flight Attendant Supervisor to come to the aircraft. The paramedics showed up as did Port Authority Police. The Port Authority Police were in the flight deck entry area talking to the Captain and asking for his info and why there was no Supervisor present. I called Operations a few more times requesting a Flight Attendant Supervisor and or any Supervisor. I informed Operations that the Port Authority [Police] required a Supervisor be there for this type of event. I was informed that the flight attendant and mechanic were both transported to the hospital to get checked. I remained in the flight deck throughout the incident relaying information to Operations and monitoring the radios and performing duties I was given.

Data retrieved from NASA's ASRS site 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.