Flight Crew Air Transport Pilot (ATP)
Workload; Troubleshooting; Time Pressure; Confusion
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft; Company Policy; Human Factors; MEL
Enroute; the left pack was on MEL; we were at FL240. About 50 miles east of ZZZ VOR we got a R ENG BLEED caution message. The FO (First Officer) had the radio and controls and I pulled out the QRH. I referenced the L/R ENG BLEED tab and as reading it I could not follow the procedure because it says to select other pack. The one that was on MEL. The cabin altitude was rising about 1000 ft per min. The FO and I agreed to descend and we told ATC that we were experiencing a pressurization problem and we would need lower. He gave us a descent to 14000 ft. On our way down the cabin alt continued to rise and we got the CABIN ALT caution message when it hit 10;000 ft. We checked the ECS (Environmental Control System) page and the right pack was off. We had no air conditioning; no pressurization; an already warm aircraft (single pack); cabin temp rising; and [a suitable airport] 80 miles away.  We decided to divert. We informed ATC and he gave us direct to ZZZ airport. We turn towards ZZZ and cleaned up the FMS. At this time the autopilot disconnected. We waited about 15 to 20 seconds and then engaged it again. It disconnected again so my FO hand flew the rest of the flight. ATC asked if we wanted to declare an emergency. We said yes and gave him the standard information; souls on board; fuel on board; etc. He also asked if we needed the trucks. We said that it was just a pressurization issue and we had full control of the aircraft so; no. We sent an ACARS message to dispatch that we lost pressurization and we were diverting to ZZZ. They responded that they copy and will let them know we are coming. During this busy time I started the CABIN ALT checklist. Again; without Packs I was unable to accomplish the procedure. It says ' If CABIN ALT caution message persists:PRESS CONT switch......................................................MANManual Cabin Pressurization Control Procedure............ ACCOMPLISH (SEE THIS TAB)'.I went to the MANUAL CABIN PRESSURIZATION CONTROL PROCEDURES. And again not having the use of the Packs I couldn't complete this procedure either. During this time I also got the ATIS; programmed the FMS; set up the cockpit for the approach briefed the approach (FO was hand flying and working the radios); call in range; advise the FAs (Flight Attendants) and run all the checklists. Our hands were full. We talked about the UNPRESSURIZED FLIGHT PROCEDURE but the descent was gradual; the cabin alt was within 200 ft of the altimeter and keeping pace; differential pressure was zero; and we would have to take delay vectors to accomplish it or sacrifice some landing procedures. We opted to make a safe non-rushed approach and landing. We kept the FAs in the loop the entire time. The initial descent and after we decided to divert. We had total flight control of the aircraft and told them there was no need to brace the Pax. After landing the Tower Controller asked if we needed any assistance. We said no only to taxi directly to the gate because we had no air conditioning. He gave us that. We arrived on the ramp abeam our gate. No Rampers. We called Ops and asked for marshaling into the gate ASAP because we had no A/C. We waited about 5 mins for them.  The cabin temp rapidly rising in the 102 degree sun. When they strolled out; they had to move a baggage cart that was within the safety diamond. This was an aircraft with an emergency. It matters not what the emergency is; they should be waiting and ready. This could have turned into a medical emergency and we have nonchalant ramp personnel moseying out to an aircraft in distress.
The Captain reported being dispatched with one inoperative air conditioning pack. At cruise altitude; a bleed air malfunction affecting the remaining pack resulted in loss of cabin pressure and an inability to control the cabin temperature. An emergency was declared and the flight successfully diverted to a suitable airport. The Captain expressed his concern over a company policy of dispatching aircraft on long flights with an inoperative air conditioning pack.