|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||airport : zzz.airport|
|Altitude||msl single value : 36600|
|Controlling Facilities||artcc : zzz.artcc|
|Operator||common carrier : air carrier|
|Make Model Name||B737-300|
|Operating Under FAR Part||Part 121|
|Flight Phase||climbout : vacating altitude|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Experience||flight time last 90 days : 198|
flight time type : 5100
|Anomaly||aircraft equipment problem : critical|
|Independent Detector||aircraft equipment other aircraft equipment : cabin alt warn horn|
other flight crewa
|Resolutory Action||flight crew : declared emergency|
flight crew : diverted to another airport
While climbing through FL366 to FL370; crew received a cabin altitude warning horn. Both pilots accomplished immediate action items (don oxygen masks and establish communications) referred to the QRH for cabin altitude warning horn/abnormal pressurization procedure and requested and received immediate descent clearance to FL240. Completed all steps in QRH procedure for situation; but were unable to regain control of cabin pressure. Followed additional QRH guidance and initiated emergency descent procedure to 14000 ft MSL. Pilots considered divert options and decided to divert to ZZZ. Landed uneventfully at ZZZ. Although I have practiced this very same procedure many times in the simulator (and in the aircraft in my military flying); the difficulty in communicating with the other pilot cannot be understated and presents one of the greatest threats to successful decision making in an unusual and high workload environment. Communications with ATC and the in-flight crew required much less effort than communicating with the other pilot. This '180' from the norm is counter-intuitive and simply creates another barrier in a unusual and dynamic situation. As far as the pressurization problem; I have no idea. An airplane is a machine and things sometimes malfunction. The training and QRH guidance I received have been excellent and proved more than effective at resolving the problem to a successful outcome. As far as the communication issue; a 'hot microphone' capability could certainly prove useful in this situation where 1 pilot is flying and the other is verbalizing a complex abnormal procedure while communicating with not only ATC; the in-flight crew; and passenger; but the other pilot as well.
Original NASA ASRS Text
Title: A B737-300'S PRESSURIZATION FAILED AT FL366. THE CREW DECLARED AN EMERGENCY; DESCENDED; AND DIVERTED TO NEARBY AIRPORT.
Narrative: WHILE CLBING THROUGH FL366 TO FL370; CREW RECEIVED A CABIN ALT WARNING HORN. BOTH PLTS ACCOMPLISHED IMMEDIATE ACTION ITEMS (DON OXYGEN MASKS AND ESTABLISH COMS) REFERRED TO THE QRH FOR CABIN ALT WARNING HORN/ABNORMAL PRESSURIZATION PROC AND REQUESTED AND RECEIVED IMMEDIATE DSCNT CLRNC TO FL240. COMPLETED ALL STEPS IN QRH PROC FOR SITUATION; BUT WERE UNABLE TO REGAIN CTL OF CABIN PRESSURE. FOLLOWED ADDITIONAL QRH GUIDANCE AND INITIATED EMER DSCNT PROC TO 14000 FT MSL. PLTS CONSIDERED DIVERT OPTIONS AND DECIDED TO DIVERT TO ZZZ. LANDED UNEVENTFULLY AT ZZZ. ALTHOUGH I HAVE PRACTICED THIS VERY SAME PROC MANY TIMES IN THE SIMULATOR (AND IN THE ACFT IN MY MIL FLYING); THE DIFFICULTY IN COMMUNICATING WITH THE OTHER PLT CANNOT BE UNDERSTATED AND PRESENTS ONE OF THE GREATEST THREATS TO SUCCESSFUL DECISION MAKING IN AN UNUSUAL AND HIGH WORKLOAD ENVIRONMENT. COMS WITH ATC AND THE INFLT CREW REQUIRED MUCH LESS EFFORT THAN COMMUNICATING WITH THE OTHER PLT. THIS '180' FROM THE NORM IS COUNTER-INTUITIVE AND SIMPLY CREATES ANOTHER BARRIER IN A UNUSUAL AND DYNAMIC SITUATION. AS FAR AS THE PRESSURIZATION PROB; I HAVE NO IDEA. AN AIRPLANE IS A MACHINE AND THINGS SOMETIMES MALFUNCTION. THE TRAINING AND QRH GUIDANCE I RECEIVED HAVE BEEN EXCELLENT AND PROVED MORE THAN EFFECTIVE AT RESOLVING THE PROB TO A SUCCESSFUL OUTCOME. AS FAR AS THE COM ISSUE; A 'HOT MIKE' CAPABILITY COULD CERTAINLY PROVE USEFUL IN THIS SITUATION WHERE 1 PLT IS FLYING AND THE OTHER IS VERBALIZING A COMPLEX ABNORMAL PROC WHILE COMMUNICATING WITH NOT ONLY ATC; THE INFLT CREW; AND PAX; BUT THE OTHER PLT AS WELL.
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.