Air carrier flight crew reported an APU failure after push back with high outside temperatures. The cabin temperature became excessive and passengers became ill. The flight requested an immediate return to any gate; which was eventually granted.
Synopsis
Air carrier flight crew reported an APU failure after push back with high outside temperatures. The cabin temperature became excessive and passengers became ill. The flight requested an immediate return to any gate; which was eventually granted.
Narrative
After pushing off the gate we positioned on the ramp waiting for a controlled departure time to ZZZ1. We had the APU running and #2 Engine running. The APU FAULT light illuminated; and the APU shut down. We complied with the QRH and attempted another start unsuccessfully. We contacted Maintenance Control for guidance and possible MEL relief. Maintenance Control instructed another restart which was also unsuccessful; and we required an inspection of the tail cone area before applying the MEL. At this point; we received a call from the Flight Attendant to inform us it was getting hot in the cabin. It was 115 degrees Fahrenheit outside; and the loss of the APU severely affected our ability to cool the cabin. We requested a gate return with ZZZ Station Ops and were informed that Gate X was occupied and was the only available gate. We received another call from the Flight Attendant indicating that it was extremely hot now in the cabin. Our flight deck gauge was indicating 98 degrees. We again requested a gate from Operations and were told we must wait until the aircraft at Gate X pushed. The Flight Attendants served water and then we repositioned on the ramp in order to push up the thrust lever on the #2 Engine in order to increase airflow of the conditioned air. The #2 Engine oil temperature immediately increased into the amber range; and we reduced thrust back to idle to maintain the engine within limits. I called the operations control and spoke to the Chief Pilot on Call to convey that this was a dangerous situation and unacceptable. We needed a gate ASAP as we had no way to cool the cabin below 98 degrees. The next call from the Flight Attendant informed us that several passengers had passed out unconscious. We again contacted Operations and informed them that we now had a medical emergency on our aircraft with several unconscious passengers. We were told they were attempting to get us a gate. We pleaded for any gate including other airline gates We were off the gate for 68 minutes by the time we parked back at the gate.Suggestion: 'This situation is unacceptable and dangerous. It is not a stretch to say that we could have had a fatality. I believe the urgency to find us a gate in this dire circumstance was wholly inadequate. Our operation at ZZZ is not prepared for a contingency like this; and that again; is both dangerous and unacceptable.'
Second reporter narrative
We pushed back from Gate X and started Engine #2 with the APU during normal operations. Following the Engine #2 start the APU Fault light illuminated; we performed the QRH procedure and attempted another APU start in accordance with the QRH. This attempt failed as well; and the Captain began communication with the Manager on Call. During this time; I was communicating with the Cabin Crew; as the cabin temperature was increasing. We began to take actions in accordance with Manager on Call instructions to try and recover the APU; these attempts failed; and Manager on Call stated we should return to the gate to allow Contract Maintenance to MEL the APU. At this point we knew the aircraft cabin temperature would continue to increase and asked Ground Control to reposition on the ramp; so we could use more engine RPM for better conditioned air/and or attempt a crossbleed start of Engine #1. As soon as we cleared the gate another Company aircraft utilized this gate; eliminating that option. The Captain increased N2 to around 30-35% power and almost immediately a flashing Amber box appeared around the secondary engine parameters indicating Engine Oil Temperature was exceeding normal parameters; it was around 145. After he returned the power back to Idle it settled around 139 and we concluded a crossbleed start would not be possible; without exceeding the Oil Temp limits. At this point a lot was going on; continuous communication with the Cabin Crew; the Captain was on the phone with the operations control; and I was trying to convince Operations to resource another gate; even if it was another airline's gate. Several times I reminded them the importance to get a gate soon; as the cabin temperature was now over 95; it eventually settled at 98. They eventually received access to (other carrier) aircraft's Gate YZ or YA. Also; the outside air temperature was 115F.Suggestion: 'The station needs to have contingencies for these types of events; even if it means ceasing ground operations on the aircraft on the only available company gate to marshal another aircraft to an open gate. Ideally at small stations; we need access to any available gate for events that are not normal and safety of the crew and passengers is a concern.'
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.