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First officer of cpr light transport activated the cabin pressurization dump switch when trying to change from automatic to manual control of the system.
| Attributes | |
| ACN | 145672 |
| Time | |
| Date | 199005 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : phx |
| State Reference | AZ |
| Altitude | msl bound lower : 12000 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zab |
| Operator | general aviation : corporate |
| Make Model Name | Light Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 100 flight time total : 7400 flight time type : 300 |
| ASRS Report | 145672 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : declared emergency flight crew : overcame equipment problem |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
Narrative:
PNF noticed that the cabin was climbing slowly. PNF decided to correct the pressurization problem by switching from automatic mode to manual mode. PNF moved the wrong switch and instead moved the cabin dump switch. Cabin pressurization was lost and a rapid descent to 12000' was started. Upon reaching 12000' the cabin pressure was reestablished and a climb back to FL370 was began. Moral of the story: confer with other crew members before moving a switch (ex fuel transfer, cabin altitude, etc). Confirm in your own mind what switch you have in your hand before any action. Act slowly and thoughtfully as a team.
Original NASA ASRS Text
Title: FO OF CPR LTT ACTIVATED THE CABIN PRESSURIZATION DUMP SWITCH WHEN TRYING TO CHANGE FROM AUTO TO MANUAL CTL OF THE SYSTEM.
Narrative: PNF NOTICED THAT THE CABIN WAS CLIMBING SLOWLY. PNF DECIDED TO CORRECT THE PRESSURIZATION PROBLEM BY SWITCHING FROM AUTO MODE TO MANUAL MODE. PNF MOVED THE WRONG SWITCH AND INSTEAD MOVED THE CABIN DUMP SWITCH. CABIN PRESSURIZATION WAS LOST AND A RAPID DESCENT TO 12000' WAS STARTED. UPON REACHING 12000' THE CABIN PRESSURE WAS REESTABLISHED AND A CLIMB BACK TO FL370 WAS BEGAN. MORAL OF THE STORY: CONFER WITH OTHER CREW MEMBERS BEFORE MOVING A SWITCH (EX FUEL TRANSFER, CABIN ALT, ETC). CONFIRM IN YOUR OWN MIND WHAT SWITCH YOU HAVE IN YOUR HAND BEFORE ANY ACTION. ACT SLOWLY AND THOUGHTFULLY AS A TEAM.
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.