|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||airport : zzz.airport|
|Altitude||msl single value : 35000|
|Controlling Facilities||artcc : zzz.artcc|
|Operator||common carrier : air carrier|
|Make Model Name||A320|
|Operating Under FAR Part||Part 121|
|Flight Phase||cruise : level|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Experience||flight time last 90 days : 160|
flight time total : 7000
flight time type : 400
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Anomaly||aircraft equipment problem : critical|
|Independent Detector||aircraft equipment other aircraft equipment : cabin altitude indicator|
other flight crewa
other flight crewb
|Resolutory Action||controller : issued new clearance|
flight crew : declared emergency
flight crew : diverted to another airport
flight crew : landed in emergency condition
Flight Crew Human Performance
Maintenance Human Performance
Aircraft was dispatched from lax with a deferred automatic pressurization controller. Checks on aircraft on the ground indicated normal operation of the remaining automatic controller. At a cruise altitude of FL350 approximately 150 NM west of ZZZ; sudden indication of cabin pressure greater than 13000 ft occurred! This was simultaneous with the ECAM of dual automatic pressurization controller failure indications. Instantly the first officer and I ran the qrc and donned our oxygen and established crew communication as well as initiated a descent to what was a safe altitude at that distance from ZZZ of 10000 ft. We were later asked by ATC to stop at 11000 ft and then climbed to 12000 ft to comply with the MSA within 25 NM of ZZZ VOR from our direction. Later we were allowed to descend prior to holding at ZZZ VOR down to 10000 ft as all the high terrain in the area was well north of our position. We declared an emergency and squawked 7700 (later we were asked to squawk xyza). Initially; after starting the descent; the feeling of the crew was that the indications could be erroneous as there was no significant pressure changes in the cockpit and this was supported by our communication with the flight attendants that they were fine and that the oxygen masks had not deployed automatically. The first officer noted in the emergency descent the cabin altitude indicating as high as FL200. The crew; however; followed the checklist and advised the flight attendants that we would err on the conservative side and manually deploy the passenger masks from the cockpit. This worked well and with a thorough explanation to the flight attendants and passenger on the PA; everyone seemed pretty calm. At the time; the flight attendants stated that they felt fine; however; on the bus ride the next day; they reported that they were starting to feel a little lightheaded. This deployment of masks and communication occurred about FL280-FL250. After descending to 11000 ft; it was apparent that the cabin pressure could not be reduced below 13600 ft and the highest rate of descent we could get the controller to in manual was 150-300 FPM down. All the while we communicated with the flight attendants to make sure they were on oxygen and everyone was feeling ok. We told the flight attendants to perform a cabin advisory; as well as to make sure the passenger knew how to clear their ears. With the autoplt on; the captain initiated a 'call me' with dispatch and maintenance. They informed us to go to 131.3 but no contact was made with them in the air other than the first officer manually typing into ACARS. Dispatch informed us early on our maximum landing weight for ZZZ was 170000 pounds. At that time we were about 150000 pounds; however; a hvywt landing checklist would have to be performed before the A320 passenger for the limits section is 142.2. The captain had already informed dispatch that ZZZ was the desired field due to clear WX and a 13000 ft runway on runway 8; for the possible heavier than normal landing. After landing; the first officer reminded everyone to 'remain seated' and we taxied clear of the runway without incident and chose to stop on the parallel taxiway a prior to continuing on to the gate in order to continue working the pressurization problem there versus the gate area. The cabin pressure still indicated 13900 ft upon touchdown. We also noted that the outflow valve had not opened upon landing and we were unable to depressurize the jet at that time. Our confign was packs off in accordance with the overweight landing check and bleeds on. We attempted manual control again and in accordance with the ECAM we ran the vertical speed all the way up. This resulted in an overpressurization feeling which included pressure changes on the ears. We decided to lower the vertical speed maximum down again as it was at least comfortable there. Once again we only got to 13600 ft and 150-200 FPM descent rate. Finally we were able to partially talk to maintenance on 131.3; however; it was poor and the captain used his cell phone to make contact and work out the rest of the issues. Maintenance directed us to pull circuit breaker D-9. This initially resulted in a cabin pressure indication on the system display of -5500 and about 15 seconds later it went back to 13900 ft. Samc directed us to break the collar on circuit breaker Y-22 which was the deferred automatic controller and in addition we placed the controller in automatic again. This resulted in the same display of -5500 and then 15 seconds later back to 13900 ft. All this time I had the first officer on oxygen just in case; while I felt fine but continued to have my mask in my lap and close at hand. Then we tried shutting off the bleeds to no avail. Finally we asked maintenance what he thought about us shutting down the engines. This resulted in the outflow valve opening and the cabin altitude initially indicated -5500 with amber vertical speed rate of 2900 FPM; however; no pressurization changes were noted which still made us feel something was erroneous.; we had the flight attendant open 1L only after confirming that it was disarmed and informed her to hold the door loosely when opening it as well as to hold on to the support at the door. All this was accomplished only after we confirmed pressure was equal on the gauges and that her cabin pressure lights on the doors were not illuminated (indicating equal pressure) and ensuring everyone was in their seats with their seatbelts fastened. The door opened without incident. We finally made contact with station operations and asked for a tow; which could not be done since ATC did not want them to taxi across the perpendicular runway 35 at night. Instead; we chose a single engine taxi with the first officer's window open all the time to prevent pressurization. We taxied to the gate which was not on the 10-7 page without any further incidents.
Original NASA ASRS Text
Title: AN A320 IN CRUISE AT FL350 HAD SUDDEN INDICATION OF CABIN ALT OF 13000 FT. MADE EMER DSCNT TO 10000 FT. LOSS OF COMPLETE PRESSURIZATION CTL.
Narrative: ACFT WAS DISPATCHED FROM LAX WITH A DEFERRED AUTO PRESSURIZATION CONTROLLER. CHKS ON ACFT ON THE GND INDICATED NORMAL OP OF THE REMAINING AUTO CONTROLLER. AT A CRUISE ALT OF FL350 APPROX 150 NM W OF ZZZ; SUDDEN INDICATION OF CABIN PRESSURE GREATER THAN 13000 FT OCCURRED! THIS WAS SIMULTANEOUS WITH THE ECAM OF DUAL AUTO PRESSURIZATION CONTROLLER FAILURE INDICATIONS. INSTANTLY THE FO AND I RAN THE QRC AND DONNED OUR OXYGEN AND ESTABLISHED CREW COM AS WELL AS INITIATED A DSCNT TO WHAT WAS A SAFE ALT AT THAT DISTANCE FROM ZZZ OF 10000 FT. WE WERE LATER ASKED BY ATC TO STOP AT 11000 FT AND THEN CLBED TO 12000 FT TO COMPLY WITH THE MSA WITHIN 25 NM OF ZZZ VOR FROM OUR DIRECTION. LATER WE WERE ALLOWED TO DSND PRIOR TO HOLDING AT ZZZ VOR DOWN TO 10000 FT AS ALL THE HIGH TERRAIN IN THE AREA WAS WELL N OF OUR POS. WE DECLARED AN EMER AND SQUAWKED 7700 (LATER WE WERE ASKED TO SQUAWK XYZA). INITIALLY; AFTER STARTING THE DSCNT; THE FEELING OF THE CREW WAS THAT THE INDICATIONS COULD BE ERRONEOUS AS THERE WAS NO SIGNIFICANT PRESSURE CHANGES IN THE COCKPIT AND THIS WAS SUPPORTED BY OUR COM WITH THE FLT ATTENDANTS THAT THEY WERE FINE AND THAT THE OXYGEN MASKS HAD NOT DEPLOYED AUTOMATICALLY. THE FO NOTED IN THE EMER DSCNT THE CABIN ALT INDICATING AS HIGH AS FL200. THE CREW; HOWEVER; FOLLOWED THE CHKLIST AND ADVISED THE FLT ATTENDANTS THAT WE WOULD ERR ON THE CONSERVATIVE SIDE AND MANUALLY DEPLOY THE PAX MASKS FROM THE COCKPIT. THIS WORKED WELL AND WITH A THOROUGH EXPLANATION TO THE FLT ATTENDANTS AND PAX ON THE PA; EVERYONE SEEMED PRETTY CALM. AT THE TIME; THE FLT ATTENDANTS STATED THAT THEY FELT FINE; HOWEVER; ON THE BUS RIDE THE NEXT DAY; THEY RPTED THAT THEY WERE STARTING TO FEEL A LITTLE LIGHTHEADED. THIS DEPLOYMENT OF MASKS AND COM OCCURRED ABOUT FL280-FL250. AFTER DSNDING TO 11000 FT; IT WAS APPARENT THAT THE CABIN PRESSURE COULD NOT BE REDUCED BELOW 13600 FT AND THE HIGHEST RATE OF DSCNT WE COULD GET THE CONTROLLER TO IN MANUAL WAS 150-300 FPM DOWN. ALL THE WHILE WE COMMUNICATED WITH THE FLT ATTENDANTS TO MAKE SURE THEY WERE ON OXYGEN AND EVERYONE WAS FEELING OK. WE TOLD THE FLT ATTENDANTS TO PERFORM A CABIN ADVISORY; AS WELL AS TO MAKE SURE THE PAX KNEW HOW TO CLR THEIR EARS. WITH THE AUTOPLT ON; THE CAPT INITIATED A 'CALL ME' WITH DISPATCH AND MAINT. THEY INFORMED US TO GO TO 131.3 BUT NO CONTACT WAS MADE WITH THEM IN THE AIR OTHER THAN THE FO MANUALLY TYPING INTO ACARS. DISPATCH INFORMED US EARLY ON OUR MAX LNDG WT FOR ZZZ WAS 170000 LBS. AT THAT TIME WE WERE ABOUT 150000 LBS; HOWEVER; A HVYWT LNDG CHKLIST WOULD HAVE TO BE PERFORMED BEFORE THE A320 PAX FOR THE LIMITS SECTION IS 142.2. THE CAPT HAD ALREADY INFORMED DISPATCH THAT ZZZ WAS THE DESIRED FIELD DUE TO CLR WX AND A 13000 FT RWY ON RWY 8; FOR THE POSSIBLE HEAVIER THAN NORMAL LNDG. AFTER LNDG; THE FO REMINDED EVERYONE TO 'REMAIN SEATED' AND WE TAXIED CLR OF THE RWY WITHOUT INCIDENT AND CHOSE TO STOP ON THE PARALLEL TXWY A PRIOR TO CONTINUING ON TO THE GATE IN ORDER TO CONTINUE WORKING THE PRESSURIZATION PROB THERE VERSUS THE GATE AREA. THE CABIN PRESSURE STILL INDICATED 13900 FT UPON TOUCHDOWN. WE ALSO NOTED THAT THE OUTFLOW VALVE HAD NOT OPENED UPON LNDG AND WE WERE UNABLE TO DEPRESSURIZE THE JET AT THAT TIME. OUR CONFIGN WAS PACKS OFF IN ACCORDANCE WITH THE OVERWT LNDG CHK AND BLEEDS ON. WE ATTEMPTED MANUAL CTL AGAIN AND IN ACCORDANCE WITH THE ECAM WE RAN THE VERT SPD ALL THE WAY UP. THIS RESULTED IN AN OVERPRESSURIZATION FEELING WHICH INCLUDED PRESSURE CHANGES ON THE EARS. WE DECIDED TO LOWER THE VERT SPD MAX DOWN AGAIN AS IT WAS AT LEAST COMFORTABLE THERE. ONCE AGAIN WE ONLY GOT TO 13600 FT AND 150-200 FPM DSCNT RATE. FINALLY WE WERE ABLE TO PARTIALLY TALK TO MAINT ON 131.3; HOWEVER; IT WAS POOR AND THE CAPT USED HIS CELL PHONE TO MAKE CONTACT AND WORK OUT THE REST OF THE ISSUES. MAINT DIRECTED US TO PULL CIRCUIT BREAKER D-9. THIS INITIALLY RESULTED IN A CABIN PRESSURE INDICATION ON THE SYS DISPLAY OF -5500 AND ABOUT 15 SECONDS LATER IT WENT BACK TO 13900 FT. SAMC DIRECTED US TO BREAK THE COLLAR ON CIRCUIT BREAKER Y-22 WHICH WAS THE DEFERRED AUTO CONTROLLER AND IN ADDITION WE PLACED THE CONTROLLER IN AUTO AGAIN. THIS RESULTED IN THE SAME DISPLAY OF -5500 AND THEN 15 SECONDS LATER BACK TO 13900 FT. ALL THIS TIME I HAD THE FO ON OXYGEN JUST IN CASE; WHILE I FELT FINE BUT CONTINUED TO HAVE MY MASK IN MY LAP AND CLOSE AT HAND. THEN WE TRIED SHUTTING OFF THE BLEEDS TO NO AVAIL. FINALLY WE ASKED MAINT WHAT HE THOUGHT ABOUT US SHUTTING DOWN THE ENGS. THIS RESULTED IN THE OUTFLOW VALVE OPENING AND THE CABIN ALT INITIALLY INDICATED -5500 WITH AMBER VERT SPD RATE OF 2900 FPM; HOWEVER; NO PRESSURIZATION CHANGES WERE NOTED WHICH STILL MADE US FEEL SOMETHING WAS ERRONEOUS.; WE HAD THE FLT ATTENDANT OPEN 1L ONLY AFTER CONFIRMING THAT IT WAS DISARMED AND INFORMED HER TO HOLD THE DOOR LOOSELY WHEN OPENING IT AS WELL AS TO HOLD ON TO THE SUPPORT AT THE DOOR. ALL THIS WAS ACCOMPLISHED ONLY AFTER WE CONFIRMED PRESSURE WAS EQUAL ON THE GAUGES AND THAT HER CABIN PRESSURE LIGHTS ON THE DOORS WERE NOT ILLUMINATED (INDICATING EQUAL PRESSURE) AND ENSURING EVERYONE WAS IN THEIR SEATS WITH THEIR SEATBELTS FASTENED. THE DOOR OPENED WITHOUT INCIDENT. WE FINALLY MADE CONTACT WITH STATION OPS AND ASKED FOR A TOW; WHICH COULD NOT BE DONE SINCE ATC DID NOT WANT THEM TO TAXI ACROSS THE PERPENDICULAR RWY 35 AT NIGHT. INSTEAD; WE CHOSE A SINGLE ENG TAXI WITH THE FO'S WINDOW OPEN ALL THE TIME TO PREVENT PRESSURIZATION. WE TAXIED TO THE GATE WHICH WAS NOT ON THE 10-7 PAGE WITHOUT ANY FURTHER INCIDENTS.
Data retrieved from NASA's ASRS site as of January 2009 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.