<< >> NASA ASRS Report 633812, October 2004

MD83 crew was unable to control cabin pressurization. Both pack switches were found in the off position.

Attributes
ACN	633812
Time
Date	200410
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zkc.artcc
State Reference	KS
Altitude	msl single value : 24000
Environment
Weather Elements	Rain
Light	Night
Aircraft 1
Controlling Facilities	artcc : zkc.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	633812
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical non adherence : company policies non adherence : published procedure non adherence : far other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : cabin alt light flow light other flight crewa other flight crewb
Resolutory Action	other
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

MD83 level at FL240 with pilot's discretion to 12000 ft and best forward speed. Flow light on overhead panel was noted on. Turned rate knob with no effect. With cabin rising at maximum rate, went to kitbag for checklist for flow light on procedure. While locating procedure, the cabin altitude light illuminated. That changed procedure to red box item, cabin decompression. During expanded checklist, noticed both pack switches were off. Turned packs back on and regained control of cabin pressure. In hindsight I thought that maybe switches were inadvertently turned off after a couple of logbook write-ups placing it (logbook) on the glareshield and then (when) putting it away bumping the (pack) switches to off.

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Original NASA ASRS Text

Title: MD83 CREW WAS UNABLE TO CTL CABIN PRESSURIZATION. BOTH PACK SWITCHES WERE FOUND IN THE OFF POS.

Narrative: MD83 LEVEL AT FL240 WITH PLT'S DISCRETION TO 12000 FT AND BEST FORWARD SPD. FLOW LIGHT ON OVERHEAD PANEL WAS NOTED ON. TURNED RATE KNOB WITH NO EFFECT. WITH CABIN RISING AT MAX RATE, WENT TO KITBAG FOR CHKLIST FOR FLOW LIGHT ON PROC. WHILE LOCATING PROC, THE CABIN ALT LIGHT ILLUMINATED. THAT CHANGED PROC TO RED BOX ITEM, CABIN DECOMPRESSION. DURING EXPANDED CHKLIST, NOTICED BOTH PACK SWITCHES WERE OFF. TURNED PACKS BACK ON AND REGAINED CTL OF CABIN PRESSURE. IN HINDSIGHT I THOUGHT THAT MAYBE SWITCHES WERE INADVERTENTLY TURNED OFF AFTER A COUPLE OF LOGBOOK WRITE-UPS PLACING IT (LOGBOOK) ON THE GLARESHIELD AND THEN (WHEN) PUTTING IT AWAY BUMPING THE (PACK) SWITCHES TO OFF.

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.