Date: 202008
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: Air Conditioning and Pressurization Pack
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Confusion; Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: FO (First Officer) and I left the hotel to have breakfast together at the airport as the food available at the hotel is limited. After breakfast we proceeded to the departure gate.The aircraft was extremely hot when we first boarded and there was no airflow. While I briefed Purser and the cabin crew; FO went to the cockpit to try to cool down the airplane.He noticed the compartment temperatures were 94 degrees and the APU (Auxiliary Power Unit) was not running. He started the APU and turned the packs on. When he returned from the walk around; he mentioned that the PC air was hooked up but not turned on.I relayed the situation to station operations; and they said that they had contacted maintenance some time ago to start the APU. When boarding began the aircraft was still very warm; the compartment temperatures read 84 degrees. Later in the boarding process the Customer Service Agent mentioned that they had called 3 times about the air conditioning issue as well.The departure; climb; and early cruise were normal. At FL390 and after approximately an hour into the flight we setup for a restroom break. When I left the flight deck; I noticed how warm it still was in the cabin. After returning to the cockpit I checked the cabin temperature indication and saw that they remained high at 82 to 84 degrees and that the temperature selectors were near full cold. I also noticed the cabin altitude seemed unusually high. While FO was in restroom; I moved the temperature selectors to full warm to clear any ice that might have built up in the packs. After a minute or two there was no change; so I began the first steps of the Cabin Temperature Hot Procedure (2.20.24).Step 8 in the procedure calls for turning off the left pack. I was reluctant to do that as the air flow seemed low already and I was concerned about pressurization. FO had returned to the cockpit by this time; and I began to suspect the possibility that the recirculation fans may not be operatingcorrectly. I then asked FO to try cycling the recirculation fans. While I meant in my mind the right recirculation fan only; I did say fans (plural). FO promptly complied with my request and turned both recirculation fans off and then on. With a sinking feeling in my chest; I immediately heard the overboard exhaust valve open in the belly of the plane. I then checked the cabin pressurization panel and saw it starting to climb.I immediately called it to FO's attention and asked him to contact ATC (Air Traffic Control) for a lower altitude. I wanted to make sure that everyone in the cabin was near an oxygen mask; so I turned on the seat belt sign and called Purser and told him to get the crew to their jumpseats. I then made a PA 'Flight Attendants; take your jumpseat.' While we were in the descent; the cabin altitude warning sounded. We completed the immediate action items; started the CABIN ALTITUDE QRC; and advised ATC. Very quickly in the descent the cabin altitude began to descend. The cabin altitude warning went out; and we completed the QRC (Quick Reference Checklist) as control of the cabin had been regained. We leveled off at FL230 as the cabin altitude was well below 10;000 ft. During the descent; the cabin temperature returned to normal at approximately 74 degrees.As there is no SATCOM; we contacted dispatch via ACARS 'CALL ME'. We spoke to them on AIRINC VHF;but the frequency had gaps and we had difficulty discussing the issue with the Dispatcher and [Maintenance Control]. I'm not certain for the cause of this. I was having no difficulty with ATC communication; but there werenumerous breaks where we could not talk to dispatch. We asked dispatch to calculate our fuel burn for a flight to ZZZ.I briefed the Flight Attendants on the situation. I made a PA to the customers explaining that we were having difficulties with the air conditioning system; and I apologized for the abrupt descent. I assuredthem that there was no need for concern and that we were considering an alternate route to ZZZ. I told them that I would keep them informed.With normal pressurization and temperature restored we climbed up to FL290; stopping at FL250 and FL270 to confirm that normal pressurization and air conditioning would continue. Both the FMC (Flight Management Computer) and Dispatch showed us landing at ZZZ with acceptable reserves at FL290. Dispatch advised us that therewere no delays into ZZZ. The only weather concern was a storm cell over ZZZ1 that we had in sight and was easily detoured around.After consulting with Dispatch and FO I cancelled the priority request. ATC then recleared us to ZZZ VOR and then ZZZ1 VOR for the STAR arrival. I updated the passengers and gave them our new ETA. Subsequent arrival and landing normal.After arrival at ZZZ; I completed ELB (Electronic Flight Bag) entries. Dispatch advised us earlier that a Mechanic would meet the flight to discuss the write up. We called Maintenance as no one met the flight. They told us they would call someone for us. We waited for another approximately :15 but no one arrived. We had to leave as our next flight was departing from the other concourse.Before the Cabin Crew left; I asked them if there was any concern by the passengers and how things went from their eyes. They all complimented FO and I and said that not a single passenger had expressed any concern at all. They appreciated the communication and thanked us for our consideration and professionalism.On our way to the next flight I contacted the FODM and debriefed her on the event. As we were on the concourse; I asked her to email me some sort of confirmation and her name; but as of this writing thathas not arrived.On our flight to ZZZ1 FO and I reflected on what went well and what could have gone better.Obviously starting the APU or turning on the PC air to cool the airplane prior to our arrival would have helped things. The poor airflow in the aircraft was likely a factor as well. In my experience it takes an awfully long time to cool off an airplane that has been allowed to get that hot on the ground. But; normally once airborne with cooler exterior temperatures and the packs running on the engine bleeds the aircraft will cool before the top of climb.However; the most important error was when I asked FO to cycle both recirculation fans. Equally important was not leaving the left recirculation fan off when I knew the overboard exhaust valve hadopened. Doing so would have put the left pack in high flow and it is possible that the cabin would not have climbed like it did. This lacking in systems knowledge on my part has been corrected with avengeance over the last 24 hours. Repair of this error took the next hour of the flight.My communication and monitor/cross check was lacking regarding the issue of 'fan' v 'fans.' This is a lesson I have learned extremely well from this and will use it to teach with in the future. The precision of the spoken word is often casual; but at times and situations like this it is critical that time be taken to convey a precise message. The B756 Flight Manual had the information and resources I needed to address the situation. However; my concerns over pressurization caused me to question turning off a pack in this situation. In retrospect; it would have been better to try turning off a pack that can be turned back on rather than open a hole in the bottom of the plane that can't be closed (even though that was not my intention).I think the planning and decision making went well. FO and I weighed the pros and cons of cancelling the priority handling and the option of diverting enroute. In each case he provided good input that helped memake the decision. As mentioned before; we did have some challenges in communicating with Dispatch to get Dispatcher's input. As I was never able to have a conversation with [Maintenance Control]I did not have the benefit of their input in the decisions. I was ableto speak to [name removed] long enough to get concurrence on cancelling the priority request but most all the communications we had were through ACARS.Our workload management went well overall. FO and I were able to separate our duties; but then come together and recreate a shared mental model of the situation.Purser; and the rest of the cabin crew also did a great job in handling the situation. The fact that none of the passengers expressed any concerns after the flight is a testament to their composure and professionalism. Please forward my thanks to them all.FO did an excellent job during this and all the flights we flew. He is very capable and experienced; and managed the flying and ATC coordination perfectly while I was tending to the other duties. He is a fantastic resource on the flight deck. I truly look forward to flying with him again.


Second narrative: As a senior line holder FO (First Officer) and since my arrival to the  fleet; I can say that in the last X+ years I fly the 767-300 about 70%; the 767-400 20% and the 757-200 10% on international route exclusively. I probably have flown the 757-300 no more than 6 times during my entire time on this fleet; of which the bulk has been this month. Which is to say I am far more familiar with the system and operations of the 767 of the four types we are qualified to fly. Aviate; Navigate and Communicate are all the same regardless of AC type; but there is something to be said for exposure to the daily operation and exposure to a specific type; in my opinion.On date my Captain was replaced by a standards Captain in need of some currency; I only mention this because within XX+ years of flying; any pilot will admit that flying with a standards Captain can be a learning experience on my many levels; to say the least. I for one; always take advantage of this situation; to seek clarification and learn. Having said that; I am also fully aware of the CRM (Crew Resource Management) dynamics and stress that may come with these opportunities. My attitude is that I always try to fly SOP (Standard Operating Procedure) and learn or question when the need arises. I have been an FO longer than I have been Captain in my career but consider myself an aviator more concern with the safety of flight than ego and hence regardless of what position I am flying; I fly with the mentality that we are both here to support each other and get from point A to B safely.Captain has been around a long time; and I found him to be very approachable and willing and wanting to pass on knowledge; which is welcomed.Our 1st day was a 11h duty day; for a total schedule break of 13.5 hours.From my previous trip I already knew that there would be no inflight meal provided on our last sector and worse the airport food court as well as the Hotel room service would be closed by the time we arrived. Furthermore the next day 1st flight also does not provide a meal; which will requires that you plan ahead and arrive to the airport to get your breakfast.The above situation combined with a short layover; travel to the airport; Covid related procedure to start the duty day and if you really want to be at the aircraft 45 minute (as per Company report criteria - not enough time in my opinion) prior to departure; creates a situation where a crew not familiar with this trips particularities; could end up been hungry throughout the night and/or half of the next day; (until you get to ZZZ where you have 1.5h break in between flights with an AC change ) and all that comes with not eating well in a 24h period. With a 13.5h break you are either going to have to decide on getting less than optimum sleep or nourishment; in my opinion. I made Captain aware of this potential situation and we decided that getting to the airport early enough to eat and get to the aircraft 1h prior would be the best course. And that's exactly what we did and is where the event of the flight starts.We arrived to the gate; and I was immediately approached by the lead gate agent; who informed me that the cabin crew could not start their duties as the cabin was extremely hot. The Gate agent told me he only had X0 passengers and that boarding was scheduled to start. I strongly recommended that he should ask us before boarding verify that the cabin would be at an acceptable temperature to board. While the Captain was briefing the Flight Attendant out near the gate; I went to the cockpit where I found the following;1- The three cabin zone thermostats indicated 95F throughout the aircraft.2- Every AIR VENT inside the cockpit was closed.3- Not one sun shade or visors where installed or used in the cockpit.4- The 757-300 was on Ground power and APU off; both recirculating fan off and window heat ON and I want to say the AC battery was off. However; I can not say with certainty; regarding battery switch.As regards to the Four points above; I was surprised to find an aircraft that had landed in ZZZ1 the day prior(where August temperatures average 85-95F and 75% humidity ).I for one always open all air vents and use any possible shade to minimize the baking affect in the flight deck. And I can not imagine what would motivate any flight crew to close all the vents etc.I started the APU; opened all vents in the cockpit and setup the AC to cool at maximum. As I left the cockpit to do my walk around and I suggested to our flight attendants that they close all window shades and open all airflow vents to help accelerate cooling. While doing my walk around I found that the Ground AC (Air Conditioning) air hose was connected to the AC but the system was not turned on. Another uncomfortable sight for me to discover; as why would the AC hose be connected but system not turned on with the APU off.Upon my return to the cockpit I noticed that only a few vent had being opened in the business class but all shades still opened. I asked the galley Flight attendant about it and was given a shrug of the shoulders. I mentioned to the Captain all that I found ( 4 points above plus no ground AC air ) and he directed me to call ops. Ops stated that they had called the mechanics various times about getting the AC cool in some manners before our arrival. Clearly this did not happen.By the time all passengers started boarding (seemed to me that somewhere along the way my suggestion fell on deaf ears) and were finished boarding 15 minutes before scheduled departure. The AC was indicating still 89F; and Purser said that passengers were complaining about the heat.By the time we got to the Runway I noted and pointed out to the captain that the temperature was still showing 85-86F.I was the flying pilot and we departed. I made it a point to mention to the captain that I would climb FL280 so as to facilitate getting to altitude and colder conditions faster; and get above the various buildups that where already starting. Furthermore because of our light weight I requested we climb to FL390.The 757-300 like the 767 has a cockpit temperature setting; without a temperature readout; but to me the cockpit felt comfortable enough. It was not until the TOC (Top Of Climb) or some minutes past that; I noticed and pointed out that the cabin temperature still showed 83-84F.However; it wasn't until about an hour into the flight; entering ZZZ1 Center that we stepped out for a bathroom break and Captain noticed that the cabin was indeed still extremely warm; especially the galley. I concur with Captain's assessment after I stepped out of the flight deck as well. By time I came back to the flight deck; Captain mentioned to me that he had reviewed and started with the procedure regarding a hot cabin or something to that effect. But that neither manual or max cooling etc were having any affect.Around this time into ZZZ1 Center and at FL390; Captain said he was going to try to see what could be done to help with this minimum cooling of the cabin; situation.He thought that perhaps the packs had frozen over; a fair and common occurrence; I agreed but did mentioned that in my past experience usually you will get some signs of this situation ie ice pellets; but that I had not seen or felt any since the gate; especially with all the humid air.As he researched more; I offered to take the radio as well PF (Pilot Flying) duties. At some point he asked me to turn off the recirculation FANs; which I repeated 'turning off both Recir Fan R n L' and executed the command.Here is where my lack of experience with the 757-300 system; combined with flying with a standards Captain; becomes more interesting as I think had I been flying with a normal line pilot; I would have requested that we use and follow the checklist. And perhaps prevented us from turning off the L Recir Fan.In this scenario I was now following his guidance and thinking that because of his position perhaps he knew of a fix or something relating to this situation learned in his day to day exposure as a standards Captain.Soon after recycling both FAN; we noticed then cabin started to climb at 300fpm from Cabin Altitude of 8;000 ft. As the cabin altitude passed 9;000 ft. I suggested we get our mask ready and the Captain asked for a lower FL. We received FL340 and I descended expeditiously. Still the cabin continued to climb and prior to getting the Cabin Altitude Warning; I had my mask on and established communications; Soon after we initiated a rapid descent to FL230 and advised ATC.The expedited descent was executed and while the Captain established radio communication; I flew the AC to FL230 and requested vectors. Once I thought Captain was regrouping with me; I requested expedited descent check list.Clearly we had moved one from a temperature control situation to a pressurization situation. However because we saw it coming I was able to make the maneuver more gentle without excessive nose dive and we reached FL230 in what seemed like a fairly quick time period never exceeding 300k nor did the cabin pressure exceed 11;000 ft.Flying at FL230 and FL290 and while I spoke to ATC; I requested vectors toward the west to avoid weather and was able to access that if need be we; could still make it to ZZZ1 with plenty of fuel.Captain had some difficulty reaching or maintaining communication with Dispatch and Maintenance; I did tried to back him up but was more focus on Flying the aircraft and maintain ATC communication. Which in it self was not a smooth process; as the frequencies provided by Center were not working well; so I requested we stay with 121.5 for a while.Hearing that Captain was unable to maintain constant communications with company; I sent an ACARS messaged to dispatch with ETA and estimated Landing fuel in ZZZ; if we chose to proceed to ZZZ flying at FL290.When the Captain and I came back together we both agreed that the AC was maintaining Cabin Altitude of 8;000 ft steady at FL230. And to make communication easier; we decided to remove our oxygen mask.We both agreed that we could make it to ZZZ at FL230 and agreed that we could try slowly climbing in increments back to no higher than FL290.I was still working the ATC radio and PF (Pilot Flying). While the Captain coordinated via ACARs with dispatch and requested a an updated OFP etc to ZZZ.With concurrence and keeping Captain aware of all altitude changes; I was able to climb to FL290 and cabin altitude was holding steady.When the Captain and I; regrouped he asked me to cancel the priority handling which I questioned him about it. My reasoning being that given the situation; why not maintain the priority handling. And that I suspected they would put us back on the filed route and that would cost us more time and fuel. He requested we cancel and he would explain it to me on the ground.As far as I could follow; he spoke to the passengers and we kept everyone informed.I told ATC that we wanted to cancel the priority status; that cabin pressurization control was regained. At which point ATC controller stated that managers standing behind him needed to confirm that we desired to cancel the priority status and if we were still on oxygen mask. I stated that we were no longer on oxygen and cabin pressure was holding. ATC seemed ok and they accepted our cancellation and rerouted us back on filed plan.The next sector gave us short cuts almost direct ZZZ. And we landed I believe with over 8k of fuel and 25 minutes early.As far as cancelling the priority handling I can see the Captain's point; specifically 'why fly an hour; if the ac is in priority status with so many other landing airport enroute.'That's a point that can be argued on either side. But my SA (Situational Awareness) was good and I believed we had enough fuel to arrive safe


Synopsis: B757 flight crew reported accidental depressurization in cruise when troubleshooting a pack malfunction.