Date: 201902
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pneumatic System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed As Precaution; Flight Crew Diverted; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Due to performance limits; it was necessary to do a max thrust; bleeds off take-off. APU to pack configuration was required as it was high altitude and the first thrust reduction (before restoring the bleeds to pressurize the aircraft) was above 10;000. On climbout; after the thrust reduction and the completion of the APU to pack after takeoff portion of the checklist; the bleeds and packs were reconfigured to normal bleed to pack operation and the APU was shut down. Moments later we got an ENG HI STAGE L light on the left engine bleed. We accomplished the 757 ENG HI STAGE L checklist and shut the left bleed air switch off and the left pack off. Now we were left with the right engine bleed air suppling the right pack to pressurize the aircraft and provide all the air conditioning.Approximately 1.5 hours after take-off and at FL370; the copilot noticed the operating pack go to high flow; as he looked up he saw the PACK INOP R; PACK OFF R and the PACK TEMP R lights illuminate. Both of us donned our oxygen masks per immediate action as the cabin was rapidly rising from approximately 6;500 feet. The First Officer reached up and quickly stabilized the situation by opening the bleed isolation valve to allow right engine bleed air to the previously shutdown left pack; as directed by earlier checklist; and he turned the left pack on. The a/c began pressurizing immediately and caught the cabin altitude at just under 9;000 feet. His quick actions saved the aircraft from depressurizing and the oxygen masks from deploying in the cabin.With only one pack operating; after multiple air system failures and our descent to a lower safer altitude well on its way; I did not feel it was a safe course of action to climb back up and continue to [destination]. I conferred with the First Officer and he was in agreement to get below 10;000' and divert. He continued to fly the aircraft and talk to ATC while I coordinated with Dispatch and [Maintenance] to divert to [a nearby alternate]. Meanwhile the one remaining air conditioning pack was pumping out exceedingly hot air; [so] we went to the standby temp control system and set it to N (normal temp) to try to get it to cool off. After about 10 minutes it was still running very hot so we turned off the trim air. Then it got very cold.I realized we may be losing our last pack and was keen to continue the divert. I briefed the purser and the passengers. I did not declare an emergency since our pressurization was still holding and we were minutes away from [our alternate] and descended below 10;000 feet. We were no longer in any immediate danger. We did not require priority handling by ATC so we accomplished our normal descent checklists and set up for the ILS approach. When checklists were complete and thoroughly briefed; we accepted a turn to final and the First Officer flew an uneventful approach and landing.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B757 flight crew reported multiple malfunctions with both air conditioning packs and diverting.