Air carrier large transport experiences an aircraft equipment problem malfunction that mandates a re...

Attributes
ACN	260523
Time
Date	199401
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cce
State Reference	FL
Altitude	msl bound lower : 29000 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zma
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer pilot : commercial
Experience	flight time last 90 days : 110 flight time total : 15000 flight time type : 150
ASRS Report	260523
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

On climb out the cockpit had no airflow and was very warm -- rest of airplane (all of cabin) was normal. At about 30000 ft the cabin altitude reached 10000 ft with a warning light. I made a descent and started back for mia. Cabin altitude stopped at 10000 ft and started down so a full emergency descent was not called for. At around 15000 ft at explosion of snow and ice came out of the cockpit air vents. This was followed by a surge of air and the pressurization indications returned to normal. With the airplane leveled at 11000 ft we consulted with company maintenance and dispatch. On the basis of the information I had and the snow/ice clearing out, with dispatch's concurrence, I resumed the flight to mex. At FL280 pressurization began acting up again with a slow rise in cabin altitude which we could not stop. Made a descent to 11000 ft and returned for an uneventful landing. The snow and ice clearing with such force, followed by normal system indications made us feel the problem was fixed after the first descent. Maintenance found a broken air conditioning pack line on the ground that was our problem.

Original NASA ASRS Text

Title: ACR LGT EXPERIENCES AN ACFT EQUIP PROB MALFUNCTION THAT MANDATES A RETURN LAND.

Narrative: ON CLBOUT THE COCKPIT HAD NO AIRFLOW AND WAS VERY WARM -- REST OF AIRPLANE (ALL OF CABIN) WAS NORMAL. AT ABOUT 30000 FT THE CABIN ALT REACHED 10000 FT WITH A WARNING LIGHT. I MADE A DSCNT AND STARTED BACK FOR MIA. CABIN ALT STOPPED AT 10000 FT AND STARTED DOWN SO A FULL EMER DSCNT WAS NOT CALLED FOR. AT AROUND 15000 FT AT EXPLOSION OF SNOW AND ICE CAME OUT OF THE COCKPIT AIR VENTS. THIS WAS FOLLOWED BY A SURGE OF AIR AND THE PRESSURIZATION INDICATIONS RETURNED TO NORMAL. WITH THE AIRPLANE LEVELED AT 11000 FT WE CONSULTED WITH COMPANY MAINT AND DISPATCH. ON THE BASIS OF THE INFO I HAD AND THE SNOW/ICE CLRING OUT, WITH DISPATCH'S CONCURRENCE, I RESUMED THE FLT TO MEX. AT FL280 PRESSURIZATION BEGAN ACTING UP AGAIN WITH A SLOW RISE IN CABIN ALT WHICH WE COULD NOT STOP. MADE A DSCNT TO 11000 FT AND RETURNED FOR AN UNEVENTFUL LNDG. THE SNOW AND ICE CLRING WITH SUCH FORCE, FOLLOWED BY NORMAL SYS INDICATIONS MADE US FEEL THE PROB WAS FIXED AFTER THE FIRST DSCNT. MAINT FOUND A BROKEN AIR CONDITIONING PACK LINE ON THE GND THAT WAS OUR PROB.

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.

Air carrier large transport experiences an aircraft equipment problem malfunction that mandates a return land.