Emergency descent performed by air carrier medium large transport after loss of cabin pressure due t...

Attributes
ACN	181758
Time
Date	199106
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cle
State Reference	OH
Altitude	msl bound lower : 10000 msl bound upper : 24000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 15000 flight time type : 6000
ASRS Report	181758
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 5800 flight time type : 2800
ASRS Report	183454
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure non adherence : far
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

We were dispatched with the right pressurization pack inoperative. In route at FL240 the left pack apparently overheated and shut down. (The F/as were complaining about how cold it was in the cabin of the aircraft so we had been turning up the temperature on the left pack. The left pack was operating in automatic mode). With the loss of pressurization we requested 14000' with the center right away and were given a left turn and started our descent right away. (No emergency was declared as we were getting lower altitude right away). At about 15000' in the descent the cabin reached 14000' and the oxy masks in the cabin did deploy. We continued the descent to 10000'. (We were on a flight plan from dca to mke). We continued to mke. We thought that we would be able to get below 14000' before the cabin would climb to 14000' so did not put on oxy masks as it is very difficult to communication in the cockpit with them on. We were busy working on lower altitude with the center, making the descent, going over the emergency checklist, communication with the F/as and advising he passengers that we didn't take time to put the oxy masks on when the cabin reached 14000' with the aircraft at 15000' as we were still descending and were at 14000' a few seconds later. None of the passengers seemed to be very upset about the incident and some thought it to be a little exciting. No emergency was declared as the center was very cooperative in getting us down and assisting in any way they could. If we had had any trouble in getting down we would have declared an emergency. It indicates that you must be very careful on a one pack operation not to overheat the good pack.

Original NASA ASRS Text

Title: EMERGENCY DESCENT PERFORMED BY ACR MLG AFTER LOSS OF CABIN PRESSURE DUE TO OVERHEATED AIR CONDITIONING PACK. ACFT CONTINUED ON TO DESTINATION AT 10000'.

Narrative: WE WERE DISPATCHED WITH THE R PRESSURIZATION PACK INOPERATIVE. IN RTE AT FL240 THE L PACK APPARENTLY OVERHEATED AND SHUT DOWN. (THE F/AS WERE COMPLAINING ABOUT HOW COLD IT WAS IN THE CABIN OF THE ACFT SO WE HAD BEEN TURNING UP THE TEMP ON THE L PACK. THE L PACK WAS OPERATING IN AUTO MODE). WITH THE LOSS OF PRESSURIZATION WE REQUESTED 14000' WITH THE CTR R AWAY AND WERE GIVEN A L TURN AND STARTED OUR DSNT R AWAY. (NO EMER WAS DECLARED AS WE WERE GETTING LOWER ALT R AWAY). AT ABOUT 15000' IN THE DSNT THE CABIN REACHED 14000' AND THE OXY MASKS IN THE CABIN DID DEPLOY. WE CONTINUED THE DSNT TO 10000'. (WE WERE ON A FLT PLAN FROM DCA TO MKE). WE CONTINUED TO MKE. WE THOUGHT THAT WE WOULD BE ABLE TO GET BELOW 14000' BEFORE THE CABIN WOULD CLB TO 14000' SO DID NOT PUT ON OXY MASKS AS IT IS VERY DIFFICULT TO COM IN THE COCKPIT WITH THEM ON. WE WERE BUSY WORKING ON LOWER ALT WITH THE CTR, MAKING THE DSNT, GOING OVER THE EMER CHKLIST, COM WITH THE F/AS AND ADVISING HE PAXS THAT WE DIDN'T TAKE TIME TO PUT THE OXY MASKS ON WHEN THE CABIN REACHED 14000' WITH THE ACFT AT 15000' AS WE WERE STILL DSNDING AND WERE AT 14000' A FEW SECS LATER. NONE OF THE PAXS SEEMED TO BE VERY UPSET ABOUT THE INCIDENT AND SOME THOUGHT IT TO BE A LITTLE EXCITING. NO EMER WAS DECLARED AS THE CTR WAS VERY COOPERATIVE IN GETTING US DOWN AND ASSISTING IN ANY WAY THEY COULD. IF WE HAD HAD ANY TROUBLE IN GETTING DOWN WE WOULD HAVE DECLARED AN EMER. IT INDICATES THAT YOU MUST BE VERY CAREFUL ON A ONE PACK OPERATION NOT TO OVERHEAT THE GOOD PACK.

Data retrieved from NASA's ASRS site as of July 2007 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.

Emergency descent performed by air carrier medium large transport after loss of cabin pressure due to overheated air conditioning pack. Aircraft continued on to destination at 10000'.