Narrative:

Cabin pressure warning light illuminated due to inadvertent 'manual' control on new digital pressurization controller for DC9. Control switched to automatic in time to control cabin pressure without passenger oxygen system deployment. Request a new yellow annunciator light be added to new pressure control system to light when control switch is in 'manual' control to possibly prevent future incidents/accidents due to inadvertent switch position. Callback conversation with reporter revealed the following information: the reporter stated the system was the new digital pressurization system being installed on the DC9 fleet. The reporter stated the switch was left in the manual mode position on the pressurization control panel and the first indication of trouble was the cabin pressure warning light illuminated. The reporter said for safety, a switch position indication light should be added to the pressurization control panel. The reporter said this problem has occurred several times to myself and others and can be trouble at night.

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Original NASA ASRS Text

Title: A DC9-30 IN CLB AT 10000 FT EXPERIENCES CABIN PRESSURE WARNING LIGHT AND DISCOVERS PRESSURIZATION SWITCH INADVERTENTLY LEFT IN MANUAL.

Narrative: CABIN PRESSURE WARNING LIGHT ILLUMINATED DUE TO INADVERTENT 'MANUAL' CTL ON NEW DIGITAL PRESSURIZATION CONTROLLER FOR DC9. CTL SWITCHED TO AUTO IN TIME TO CTL CABIN PRESSURE WITHOUT PAX OXYGEN SYS DEPLOYMENT. REQUEST A NEW YELLOW ANNUNCIATOR LIGHT BE ADDED TO NEW PRESSURE CTL SYS TO LIGHT WHEN CTL SWITCH IS IN 'MANUAL' CTL TO POSSIBLY PREVENT FUTURE INCIDENTS/ACCIDENTS DUE TO INADVERTENT SWITCH POS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE SYS WAS THE NEW DIGITAL PRESSURIZATION SYS BEING INSTALLED ON THE DC9 FLEET. THE RPTR STATED THE SWITCH WAS LEFT IN THE MANUAL MODE POS ON THE PRESSURIZATION CTL PANEL AND THE FIRST INDICATION OF TROUBLE WAS THE CABIN PRESSURE WARNING LIGHT ILLUMINATED. THE RPTR SAID FOR SAFETY, A SWITCH POS INDICATION LIGHT SHOULD BE ADDED TO THE PRESSURIZATION CTL PANEL. THE RPTR SAID THIS PROB HAS OCCURRED SEVERAL TIMES TO MYSELF AND OTHERS AND CAN BE TROUBLE AT NIGHT.

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.