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Unable to maintain airfoil anti-ice and pressurization simultaneously at FL330; MD80 makes an emergency descent to 14000 ft until out of icing condition then cancels emergency and climbs to FL250 for remainder of flight.
| Attributes | |
| ACN | 796561 |
| Time | |
| Date | 200807 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | navaid : onl.vortac |
| State Reference | NE |
| Altitude | msl single value : 33000 |
| Environment | |
| Weather Elements | Thunderstorm Ice |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zmp.artcc tracon : zzz.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | MD-83 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| ASRS Report | 796561 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | other flight crewa |
| Resolutory Action | aircraft : equipment problem dissipated flight crew : declared emergency flight crew : exited adverse environment other |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance Weather |
| Primary Problem | Aircraft |
Narrative:
Cruise FL330; engine and airfoil anti-ice on. The tail and anti-ice had just finished its cycle when the cabin altitude started climbing. All attempts to stop the climb failed. As cabin altitude reached 10000 ft we went on oxygen; declared an emergency and descended to 14000 ft. Flight attendants were called and briefed as was the company; and PA made to the passenger. No masks were deployed in the back. After descent and out of icing conditions; the pressurization began to operate normally. We canceled our emergency and climbed back to FL250 for the remainder of the flight.
Original NASA ASRS Text
Title: UNABLE TO MAINTAIN AIRFOIL ANTI-ICE AND PRESSURIZATION SIMULTANEOUSLY AT FL330; MD80 MAKES AN EMERGENCY DESCENT TO 14000 FT UNTIL OUT OF ICING CONDITION THEN CANCELS EMERGENCY AND CLIMBS TO FL250 FOR REMAINDER OF FLT.
Narrative: CRUISE FL330; ENG AND AIRFOIL ANTI-ICE ON. THE TAIL AND ANTI-ICE HAD JUST FINISHED ITS CYCLE WHEN THE CABIN ALT STARTED CLBING. ALL ATTEMPTS TO STOP THE CLB FAILED. AS CABIN ALT REACHED 10000 FT WE WENT ON OXYGEN; DECLARED AN EMER AND DSNDED TO 14000 FT. FLT ATTENDANTS WERE CALLED AND BRIEFED AS WAS THE COMPANY; AND PA MADE TO THE PAX. NO MASKS WERE DEPLOYED IN THE BACK. AFTER DSCNT AND OUT OF ICING CONDITIONS; THE PRESSURIZATION BEGAN TO OPERATE NORMALLY. WE CANCELED OUR EMER AND CLBED BACK TO FL250 FOR THE REMAINDER OF THE FLT.
Data retrieved from NASA's ASRS site as of May 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.