An air carrier brasilia-120 light transport captain inadvertently dropped the oxygen masks in flight...

Attributes
ACN	261694
Time
Date	199401
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bwg
State Reference	KY
Altitude	msl bound lower : 24000 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Brasilia EMB-120 All Series
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 5700 flight time type : 2000
ASRS Report	261694
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	other flight crewa other other : unspecified cockpit
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Cruising at FL280, our cabin altitude began to rise at 500 FPM. A descent request was made to ZID. Automatic pressurization malfunction checklist was performed which requires changing to manual control. When switching to manual mode, the captain grabbed the wrong switch ('man' passenger oxygen) and deployed automatic drop down mask in cabin. Pressurization operated normally at FL240. Note that the pressurization and oxygen control switches are closely located and visually identical, both being guarded and labeled 'man' and 'automatic.' callback conversation with reporter revealed the following information: a brasilia 120 captain hit the wrong switch and dropped the oxygen masks when he was trying to control pressurization that was malfunctioning. He admits that he is making excuses for his bad switching procedure when he states that the switches are very similar and nearly side-by-side (4 inches apart). The really bad part of this exercise was none of the passenger put on their oxygen masks -- they asked the flight attendant if they were necessary. Unfortunately, the flight attendant came to the cockpit to see if there was a pressurization emergency rather than making sure that all masks were properly put on and used.

Original NASA ASRS Text

Title: AN ACR BRASILIA-120 LTT CAPT INADVERTENTLY DROPPED THE OXYGEN MASKS IN FLT.

Narrative: CRUISING AT FL280, OUR CABIN ALT BEGAN TO RISE AT 500 FPM. A DSCNT REQUEST WAS MADE TO ZID. AUTO PRESSURIZATION MALFUNCTION CHKLIST WAS PERFORMED WHICH REQUIRES CHANGING TO MANUAL CTL. WHEN SWITCHING TO MANUAL MODE, THE CAPT GRABBED THE WRONG SWITCH ('MAN' PAX OXYGEN) AND DEPLOYED AUTOMATIC DROP DOWN MASK IN CABIN. PRESSURIZATION OPERATED NORMALLY AT FL240. NOTE THAT THE PRESSURIZATION AND OXYGEN CTL SWITCHES ARE CLOSELY LOCATED AND VISUALLY IDENTICAL, BOTH BEING GUARDED AND LABELED 'MAN' AND 'AUTO.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: A BRASILIA 120 CAPT HIT THE WRONG SWITCH AND DROPPED THE OXYGEN MASKS WHEN HE WAS TRYING TO CTL PRESSURIZATION THAT WAS MALFUNCTIONING. HE ADMITS THAT HE IS MAKING EXCUSES FOR HIS BAD SWITCHING PROC WHEN HE STATES THAT THE SWITCHES ARE VERY SIMILAR AND NEARLY SIDE-BY-SIDE (4 INCHES APART). THE REALLY BAD PART OF THIS EXERCISE WAS NONE OF THE PAX PUT ON THEIR OXYGEN MASKS -- THEY ASKED THE FLT ATTENDANT IF THEY WERE NECESSARY. UNFORTUNATELY, THE FLT ATTENDANT CAME TO THE COCKPIT TO SEE IF THERE WAS A PRESSURIZATION EMER RATHER THAN MAKING SURE THAT ALL MASKS WERE PROPERLY PUT ON AND USED.

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.