 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
An incorrect barometric setting in a DC9-30 pressurization system is not noted during the crew's preflight resulting in a momentary loss of automatic pressurization control at FL340 near austin, tx.
| Attributes | |
| ACN | 528050 |
| Time | |
| Date | 200110 |
| Day | Mon |
| Place | |
| State Reference | TX |
| Altitude | msl single value : 34000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 30 |
| Flight Phase | climbout : intermediate altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : atp pilot : cfi |
| Experience | flight time last 90 days : 225 flight time total : 15500 flight time type : 9500 |
| ASRS Report | 528050 |
| Events | |
| Anomaly | aircraft equipment problem : less severe non adherence : published procedure |
| Resolutory Action | flight crew : overcame equipment problem |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
Cabin started a climb at high rate when stepping from FL330 to FL350. Leveled FL340, put on our masks and requested FL330 from center. Went to manual control (DC9 analog system) and regained control. Went through book procedure for loss of automatic controller. Short time later first officer discovered baro setting correction set to 28.4. Reset to correct value and went back to automatic mode. No further problem. Either the inbound overnight crew intentionally set it way down or some ground person screwed with it the night before. I did not catch it during my preflight as I should have, but you can bet I will make sure and check it in the future.
Original NASA ASRS Text
Title: AN INCORRECT BAROMETRIC SETTING IN A DC9-30 PRESSURIZATION SYSTEM IS NOT NOTED DURING THE CREW'S PREFLT RESULTING IN A MOMENTARY LOSS OF AUTOMATIC PRESSURIZATION CTL AT FL340 NEAR AUSTIN, TX.
Narrative: CABIN STARTED A CLB AT HIGH RATE WHEN STEPPING FROM FL330 TO FL350. LEVELED FL340, PUT ON OUR MASKS AND REQUESTED FL330 FROM CTR. WENT TO MANUAL CONTROL (DC9 ANALOG SYSTEM) AND REGAINED CTL. WENT THROUGH BOOK PROCEDURE FOR LOSS OF AUTO CTLR. SHORT TIME LATER FO DISCOVERED BARO SETTING CORRECTION SET TO 28.4. RESET TO CORRECT VALUE AND WENT BACK TO AUTO MODE. NO FURTHER PROB. EITHER THE INBND OVERNIGHT CREW INTENTIONALLY SET IT WAY DOWN OR SOME GND PERSON SCREWED WITH IT THE NIGHT BEFORE. I DID NOT CATCH IT DURING MY PREFLT AS I SHOULD HAVE, BUT YOU CAN BET I WILL MAKE SURE AND CHK IT IN THE FUTURE.
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.