Aircraft equipment problem loss of cabin pressurization for unknown cause.

Attributes
ACN	304930
Time
Date	199505
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 10000 msl bound upper : 29000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 13000 flight time type : 3000
ASRS Report	304930
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 4500 flight time type : 200
ASRS Report	305275
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : exited adverse environment other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

The aircraft experienced a loss of cabin pressure at 29000 ft. A return to atl and descent was requested from ATC. A new heading was issued but ATC was unable to descend us due to traffic. I declared an emergency and descended using TCASII to avoid traffic (cabin altitude had reached 13000 ft at that time). No conflict was issued. Callback conversation with reporter revealed the following information: the reporter pressurized the aircraft on the ground at atl so that maintenance could trouble-shoot the problem. Nothing was found while the reporter was at the controls, and he does not know what the problem may have been. When the warning horn announced a problem, the crew attempted to get the pressurization under control to no avail. ARTCC said that there would be '2-3 mins' delay for a lower altitude. The reporter then declared an emergency and descended. There was no mask drop. The reporter filed all of the required air carrier paper work. He has not heard from the FAA on this matter.

Original NASA ASRS Text

Title: ACFT EQUIP PROB LOSS OF CABIN PRESSURIZATION FOR UNKNOWN CAUSE.

Narrative: THE ACFT EXPERIENCED A LOSS OF CABIN PRESSURE AT 29000 FT. A RETURN TO ATL AND DSCNT WAS REQUESTED FROM ATC. A NEW HDG WAS ISSUED BUT ATC WAS UNABLE TO DSND US DUE TO TFC. I DECLARED AN EMER AND DSNDED USING TCASII TO AVOID TFC (CABIN ALT HAD REACHED 13000 FT AT THAT TIME). NO CONFLICT WAS ISSUED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR PRESSURIZED THE ACFT ON THE GND AT ATL SO THAT MAINT COULD TROUBLE-SHOOT THE PROB. NOTHING WAS FOUND WHILE THE RPTR WAS AT THE CTLS, AND HE DOES NOT KNOW WHAT THE PROB MAY HAVE BEEN. WHEN THE WARNING HORN ANNOUNCED A PROB, THE CREW ATTEMPTED TO GET THE PRESSURIZATION UNDER CTL TO NO AVAIL. ARTCC SAID THAT THERE WOULD BE '2-3 MINS' DELAY FOR A LOWER ALT. THE RPTR THEN DECLARED AN EMER AND DSNDED. THERE WAS NO MASK DROP. THE RPTR FILED ALL OF THE REQUIRED ACR PAPER WORK. HE HAS NOT HEARD FROM THE FAA ON THIS MATTER.

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.