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A B737 pilot describes confusion about the aircraft's two configuration warning horn initiators: ground testing for takeoff configuration but no in-flight testing loss of cabin pressure.
| Attributes | |
| ACN | 710432 |
| Time | |
| Date | 200609 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 200 flight time total : 25000 flight time type : 22000 |
| ASRS Report | 710432 |
| Events | |
| Independent Detector | other controllera |
| Resolutory Action | none taken : unable |
| Supplementary | |
| Problem Areas | Aircraft FAA |
| Primary Problem | Aircraft |
Narrative:
I was putting this temporary revision into my flight manual; and it started me thinking about how many times over the last 28 years flying boeings (727 and 737's) I've heard or read about a crew mistaking a cabin altitude warning horn for a configuration -- sometimes with fatal consequences. For us at ZZZ air carrier; two times each flight; on the receiving and before takeoff checklists we test the takeoff configuration warning horn. So about 100 times a month or 1200 times a year; I'm training myself that this horn is a configuration horn. These numbers do not include configuration horn activation during approach and landing. We never test the horn for cabin altitude. With all the aural warnings in the cockpit (seems like hundreds) particularly in the new generation; how is it possible that we don't have a separate warning for a loss of cabin pressure? After all the progress in aircraft; dropped oxygen masks; and even accidents over the last 30 years; why are we holding onto this system?
Original NASA ASRS Text
Title: A B737 PLT DESCRIBES CONFUSION ABOUT THE ACFT'S TWO CONFIGURATION WARNING HORN INITIATORS: GND TESTING FOR TKOF CONFIGURATION BUT NO INFLT TESTING LOSS OF CABIN PRESSURE.
Narrative: I WAS PUTTING THIS TEMPORARY REVISION INTO MY FLT MANUAL; AND IT STARTED ME THINKING ABOUT HOW MANY TIMES OVER THE LAST 28 YEARS FLYING BOEINGS (727 AND 737'S) I'VE HEARD OR READ ABOUT A CREW MISTAKING A CABIN ALT WARNING HORN FOR A CONFIGURATION -- SOMETIMES WITH FATAL CONSEQUENCES. FOR US AT ZZZ ACR; TWO TIMES EACH FLT; ON THE RECEIVING AND BEFORE TKOF CHKLISTS WE TEST THE TKOF CONFIGURATION WARNING HORN. SO ABOUT 100 TIMES A MONTH OR 1200 TIMES A YEAR; I'M TRAINING MYSELF THAT THIS HORN IS A CONFIGURATION HORN. THESE NUMBERS DO NOT INCLUDE CONFIGURATION HORN ACTIVATION DURING APCH AND LNDG. WE NEVER TEST THE HORN FOR CABIN ALT. WITH ALL THE AURAL WARNINGS IN THE COCKPIT (SEEMS LIKE HUNDREDS) PARTICULARLY IN THE NEW GENERATION; HOW IS IT POSSIBLE THAT WE DON'T HAVE A SEPARATE WARNING FOR A LOSS OF CABIN PRESSURE? AFTER ALL THE PROGRESS IN ACFT; DROPPED OXYGEN MASKS; AND EVEN ACCIDENTS OVER THE LAST 30 YEARS; WHY ARE WE HOLDING ONTO THIS SYSTEM?
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.