A MD80 at FL330 had all anti-icing systems activated in thunderstorms with icing; after the pressuri...

Narrative:

[We were having a] rough ride; thunderstorms with icing; all system anti ice turned on at FL330. Pressurization flow light illuminates intermittently. Crew complies with QRH abnormal for pressurization flow light. As a precaution; crew requests lower altitude. At FL270; pressurization flow light illuminates again. [We] again complied with same QRH procedure. Crew reviews QRH procedures for emergency descent and cabin altitude warning/rapid depressurization. Cabin starts to slowly climb. Captain declares emergency for pressurization and requests lower altitude. Crew complies with QRH procedures for emergency descent and cabin altitude warning/rapid depressurization. Continued flight and landed in our scheduled destination uneventfully. No passenger oxygen masks deployed.

Original NASA ASRS Text

Title: A MD80 at FL330 had all anti-icing systems activated in thunderstorms with icing; after the PRESSURIZATION FLOW LIGHT illuminated and a descent to FL270 the crew had to declare an emergency because the cabin pressure could not be maintained.

Narrative: [We were having a] rough ride; thunderstorms with icing; all system anti ice turned on at FL330. Pressurization flow light illuminates intermittently. Crew complies with QRH abnormal for pressurization flow light. As a precaution; crew requests lower altitude. At FL270; pressurization flow light illuminates again. [We] again complied with same QRH procedure. Crew reviews QRH procedures for emergency descent and cabin altitude warning/rapid depressurization. Cabin starts to slowly climb. Captain declares emergency for pressurization and requests lower altitude. Crew complies with QRH procedures for emergency descent and cabin altitude warning/rapid depressurization. Continued flight and landed in our scheduled destination uneventfully. No passenger oxygen masks deployed.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	946766
Time
Date	201105
Local Time Of Day	1801-2400
Environment
Light	Night
Aircraft 1
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Engine Air
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Inflight Event / Encounter Weather / Turbulence

A MD80 at FL330 had all anti-icing systems activated in thunderstorms with icing; after the pressurization flow light illuminated and a descent to FL270 the crew had to declare an emergency because the cabin pressure could not be maintained.