An air carrier flight crew performed an emergency descent after a B727 cabin pressure warning horn s...

Attributes
ACN	314450
Time
Date	199508
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gve
State Reference	VA
Altitude	msl bound lower : 37000 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute airway : zid
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 250 flight time total : 17000 flight time type : 4000
ASRS Report	314450
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : overcame equipment problem flight crew : declared emergency other
Consequence	Other

Narrative:

Lost cabin pressurization control while at cruise at FL370. Called center, was told to standby. Said negative, we lost the cabin, was beginning an emergency descent, now, and would turn 45 degrees off of airway, either way, his choice. Did not hear from him immediately so we turned right, and began descent. Then we were cleared to FL240. However cabin was still uncontrolled and we needed lower. We told him this and went through FL240 to about FL230 before he issued 11000 ft. We later verified that we had declared an emergency, although the controller said nothing. I was just concerned about busting an altitude during an emergency situation. There was no conflict with other traffic, and controller seemed to not notice. Callback conversation with reporter revealed the following information: the flight crew initially looked for other causes, when the warning horn sounded. First officer states that pressurization loss is very unusual for B727-200's and they first checked other system that are integrated with a warning horn. For sound reasons the flight crew followed SOP's even though the cabin leak was very slow.

Original NASA ASRS Text

Title: AN ACR FLC PERFORMED AN EMER DSCNT AFTER A B727 CABIN PRESSURE WARNING HORN SOUNDED.

Narrative: LOST CABIN PRESSURIZATION CTL WHILE AT CRUISE AT FL370. CALLED CTR, WAS TOLD TO STANDBY. SAID NEGATIVE, WE LOST THE CABIN, WAS BEGINNING AN EMER DSCNT, NOW, AND WOULD TURN 45 DEGS OFF OF AIRWAY, EITHER WAY, HIS CHOICE. DID NOT HEAR FROM HIM IMMEDIATELY SO WE TURNED R, AND BEGAN DSCNT. THEN WE WERE CLRED TO FL240. HOWEVER CABIN WAS STILL UNCTLED AND WE NEEDED LOWER. WE TOLD HIM THIS AND WENT THROUGH FL240 TO ABOUT FL230 BEFORE HE ISSUED 11000 FT. WE LATER VERIFIED THAT WE HAD DECLARED AN EMER, ALTHOUGH THE CTLR SAID NOTHING. I WAS JUST CONCERNED ABOUT BUSTING AN ALT DURING AN EMER SIT. THERE WAS NO CONFLICT WITH OTHER TFC, AND CTLR SEEMED TO NOT NOTICE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE FLC INITIALLY LOOKED FOR OTHER CAUSES, WHEN THE WARNING HORN SOUNDED. FO STATES THAT PRESSURIZATION LOSS IS VERY UNUSUAL FOR B727-200'S AND THEY FIRST CHKED OTHER SYS THAT ARE INTEGRATED WITH A WARNING HORN. FOR SOUND REASONS THE FLC FOLLOWED SOP'S EVEN THOUGH THE CABIN LEAK WAS VERY SLOW.

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.

An air carrier flight crew performed an emergency descent after a B727 cabin pressure warning horn sounded.