An air carrier medium large transport lost control of its pressurization.

Attributes
ACN	273784
Time
Date	199406
Day	Wed
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : irk
State Reference	MO
Altitude	msl bound lower : 27000 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other descent other other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	273784
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 10830 flight time type : 2000
ASRS Report	273612
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : declared emergency flight crew : exited adverse environment flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Flight was IFR en route from las to ind. After approximately plus 45 at FL330, climbed to FL370. Note: earlier flight attendant had reported noticeable air type noise in mid cabin. Left air conditioning pack had a noisy history and had had heat exchangers replaced recently. Until climb to FL370, pressurization had been stable at FL330 with no pressurization or air conditioning irregularities. Several mins after leveloff, cabin had climbed to almost 10000 ft, at which point altitude cabin horn sounded. We declared an emergency, put our oxygen masks on. Tried to gain control of cabin. This was a slow climbing cabin approximately 200-500 FPM. We descended to FL270 and regained control of cabin. Flight was uneventful until approach into ind at which point we were cleared on ILS to runway 5R. However, when we were switched to tower, they thought we were landing on runway 5L, then cleared us to land on runway 5R.

Original NASA ASRS Text

Title: AN ACR MLG LOST CTL OF ITS PRESSURIZATION.

Narrative: FLT WAS IFR ENRTE FROM LAS TO IND. AFTER APPROX PLUS 45 AT FL330, CLBED TO FL370. NOTE: EARLIER FLT ATTENDANT HAD RPTED NOTICEABLE AIR TYPE NOISE IN MID CABIN. L AIR CONDITIONING PACK HAD A NOISY HISTORY AND HAD HAD HEAT EXCHANGERS REPLACED RECENTLY. UNTIL CLB TO FL370, PRESSURIZATION HAD BEEN STABLE AT FL330 WITH NO PRESSURIZATION OR AIR CONDITIONING IRREGULARITIES. SEVERAL MINS AFTER LEVELOFF, CABIN HAD CLBED TO ALMOST 10000 FT, AT WHICH POINT ALT CABIN HORN SOUNDED. WE DECLARED AN EMER, PUT OUR OXYGEN MASKS ON. TRIED TO GAIN CTL OF CABIN. THIS WAS A SLOW CLBING CABIN APPROX 200-500 FPM. WE DSNDED TO FL270 AND REGAINED CTL OF CABIN. FLT WAS UNEVENTFUL UNTIL APCH INTO IND AT WHICH POINT WE WERE CLRED ON ILS TO RWY 5R. HOWEVER, WHEN WE WERE SWITCHED TO TWR, THEY THOUGHT WE WERE LNDG ON RWY 5L, THEN CLRED US TO LAND ON RWY 5R.

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.