An air carrier large transport crew lost all of its cockpit emergency oxygen while en route.

Attributes
ACN	251287
Time
Date	199309
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bna airport : dfw
State Reference	TN
Altitude	msl bound lower : 25000 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise 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 : 150 flight time total : 7000
ASRS Report	251287
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

In sum: an air carrier large transport crew lost almost all of its cockpit emergency oxygen supply for an undisclosed reason. The reporting captain moved walkaround bottles to the cockpit and descended the aircraft to 25000 ft. His prior experience in altitude chambers convinced him that he could function well at that altitude in case of an explosive depressurization. The captain thinks that his company has become complacent about this type of situation as it so rarely happens. The captain suggests that the full face emergency oxygen bottle be returned to the cockpit. The captain was not available for a telecon. The reporter notes that the MEL and operating manual give guidance regarding oxygen quantity while on the ground, but make no mention of this situation while airborne.

Original NASA ASRS Text

Title: AN ACR LGT CREW LOST ALL OF ITS COCKPIT EMER OXYGEN WHILE ENRTE.

Narrative: IN SUM: AN ACR LGT CREW LOST ALMOST ALL OF ITS COCKPIT EMER OXYGEN SUPPLY FOR AN UNDISCLOSED REASON. THE RPTING CAPT MOVED WALKAROUND BOTTLES TO THE COCKPIT AND DSNDED THE ACFT TO 25000 FT. HIS PRIOR EXPERIENCE IN ALT CHAMBERS CONVINCED HIM THAT HE COULD FUNCTION WELL AT THAT ALT IN CASE OF AN EXPLOSIVE DEPRESSURIZATION. THE CAPT THINKS THAT HIS COMPANY HAS BECOME COMPLACENT ABOUT THIS TYPE OF SIT AS IT SO RARELY HAPPENS. THE CAPT SUGGESTS THAT THE FULL FACE EMER OXYGEN BOTTLE BE RETURNED TO THE COCKPIT. THE CAPT WAS NOT AVAILABLE FOR A TELECON. THE RPTR NOTES THAT THE MEL AND OPERATING MANUAL GIVE GUIDANCE REGARDING OXYGEN QUANTITY WHILE ON THE GND, BUT MAKE NO MENTION OF THIS SIT WHILE AIRBORNE.

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.