Narrative:

The climb-out was non-eventful. We reached our cruise altitude of 36;000 ft without any abnormal events or indications. Approximately 5 minutes after leveling off; the master warning indication illuminated; alerting us to a; 'cabin alt' issue. The captain and I immediately donned our oxygen masks. Afterwards; the captain initiated the checklist for; 'cabin alt/rapid depressurization.' during the process; the cabin altitude continued to climb.as the captain was in the process of completing the cabin alt checklist; the 'cabin oxygen on' annunciator illuminated. The cabin altitude continued to climb further. At approximately this time; the flight attendants chimed the cockpit. We told the flight attendants that the flight deck crew was ok; but that we were very busy and that we would give them more information shortly. We also instructed them to put on their oxygen masks. The cabin altitude was still uncontrollable after completing QRH procedures; therefore; as directed by that QRH; we decided to initiate the QRH procedure for; 'rapid descent.' the captain coordinated the descent with ATC by asking for lower; and made them aware that we needed to descend urgently. As we were cleared lower; we began to initiate the rapid descent per the QRH. The captain and I started to notice a strong burning smell as we were rapidly descending. The captain opted to shut-off the left pac due to an abnormal indication. The right pack was showing the cabin supply temperature to be maxed out hot. The temperature selector on both packs was in the auto position; at approximately the 1 o'clock position prior to the captain shutting the left pack off. We also noted that the right pac pressure was constantly 'bouncing' from zero to showing some pressure on the gauge. The flow light on the pressure control light was also constantly turning on and off. Immediately after the pack was shut off; the 'hot' smell began to diminish. As we leveled off at 10;000 feet from the rapid descent; neither pilot detected the unusual smell further.due to the rapid depressurization and the unusual 'hot' smell; the captain decided that the safest course of action would be to divert to the nearest suitable airport. I requested such an airport from ATC while the captain attempted to reach company on commercial radio. ATC noted that the weather ahead near our route was not good. Visibility at most airports ahead; to the west; were approximately 1/4 mile. However; the weather behind us; to the east; was much better. ATC told us that the weather at ZZZ was 5 kt winds; 10 mi. Visibility; and 6;000 ft. Ceiling. ZZZ was approximately 70 miles away. We received clearance from ATC to proceed directly to ZZZ. I also requested to have ATC let our company know about the diversion; since the captain was unable to reach them on arinc. The captain let the flight attendants know about our diversion; including the destination; and the approximate time to get there. The rest of the arrival was uneventful.the flight landed safely at ZZZ airport. The flight crew was ok. The flight attendants noted that 2 of the passengers were a bit shaken up by the experience; but ok. Contract maintenance arrived at the aircraft about 20 minutes after parking at ZZZ. The mechanics were able to locate a chaffed tube in the tail section that they said was responsible for the depressurization. They explained that with the air conditioning tube disconnected; that the pressurized air in the cabin was able to escape into the tail compartment; depressurizing the aircraft. The damaged tube was deemed to be beyond repair by the contract maintenance team.the tube that caused the depressurization appeared to be in very poor condition. More frequent inspection/replacement of that part and the affected systems might have prevented the rapid depressurization/diversion event to occur.

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Original NASA ASRS Text

Title: MD80 flight crew experienced a loss of cabin pressurization at FL360. After attempts to control pressurization manually are unsuccessful; a descent was initiated followed by a diversion to the nearest suitable airport. When the cabin oxygen masks dropped automatically; the flight attendants failed to put them on until instructed to do so by the Captain.

Narrative: The climb-out was non-eventful. We reached our cruise altitude of 36;000 ft without any abnormal events or indications. Approximately 5 minutes after leveling off; the Master Warning indication illuminated; alerting us to a; 'Cabin Alt' issue. The Captain and I immediately donned our oxygen masks. Afterwards; the Captain initiated the checklist for; 'Cabin Alt/Rapid Depressurization.' During the process; the cabin altitude continued to climb.As the Captain was in the process of completing the Cabin Alt Checklist; the 'Cabin Oxygen On' annunciator illuminated. The cabin altitude continued to climb further. At approximately this time; the flight attendants chimed the cockpit. We told the flight attendants that the flight deck crew was ok; but that we were very busy and that we would give them more information shortly. We also instructed them to put on their oxygen masks. The cabin altitude was still uncontrollable after completing QRH procedures; therefore; as directed by that QRH; we decided to initiate the QRH procedure for; 'Rapid Descent.' The Captain coordinated the descent with ATC by asking for lower; and made them aware that we needed to descend urgently. As we were cleared lower; we began to initiate the rapid descent per the QRH. The Captain and I started to notice a strong burning smell as we were rapidly descending. The Captain opted to shut-off the left pac due to an abnormal indication. The right pack was showing the cabin supply temperature to be maxed out hot. The temperature selector on both packs was in the auto position; at approximately the 1 o'clock position prior to the Captain shutting the left pack off. We also noted that the right pac pressure was constantly 'bouncing' from zero to showing some pressure on the gauge. The flow light on the pressure control light was also constantly turning on and off. Immediately after the pack was shut off; the 'hot' smell began to diminish. As we leveled off at 10;000 feet from the rapid descent; neither pilot detected the unusual smell further.Due to the Rapid Depressurization and the unusual 'hot' smell; the Captain decided that the safest course of action would be to divert to the nearest suitable airport. I requested such an airport from ATC while the Captain attempted to reach company on Commercial Radio. ATC noted that the weather ahead near our route was not good. Visibility at most airports ahead; to the West; were approximately 1/4 mile. However; the weather behind us; to the East; was much better. ATC told us that the weather at ZZZ was 5 kt winds; 10 mi. visibility; and 6;000 ft. ceiling. ZZZ was approximately 70 miles away. We received clearance from ATC to proceed directly to ZZZ. I also requested to have ATC let our company know about the diversion; since the Captain was unable to reach them on ARINC. The Captain let the flight attendants know about our diversion; including the destination; and the approximate time to get there. The rest of the arrival was uneventful.The flight landed safely at ZZZ Airport. The flight crew was ok. The flight attendants noted that 2 of the passengers were a bit shaken up by the experience; but ok. Contract maintenance arrived at the aircraft about 20 minutes after parking at ZZZ. The mechanics were able to locate a chaffed tube in the tail section that they said was responsible for the depressurization. They explained that with the air conditioning tube disconnected; that the pressurized air in the cabin was able to escape into the tail compartment; depressurizing the aircraft. The damaged tube was deemed to be beyond repair by the contract maintenance team.The tube that caused the depressurization appeared to be in very poor condition. More frequent inspection/replacement of that part and the affected systems might have prevented the rapid depressurization/diversion event to occur.

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.