B727 crew discovers at leveloff that crew oxygen supply has decreased to 800 psi.

Attributes
ACN	437993
Time
Date	199905
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl.airport
State Reference	GA
Altitude	msl single value : 3500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl.artcc
Operator	common carrier : air carrier
Make Model Name	B727-200
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
Qualification	pilot : cfi pilot : flight engineer pilot : multi engine pilot : atp
Experience	flight time last 90 days : 240 flight time total : 14800 flight time type : 10700
ASRS Report	437993
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe inflight encounter other non adherence : far other anomaly other
Consequence	other other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Crew departed atl atl-dtw. Shortly after leveloff in cruise, so observed crew oxygen pressure indication of approximately 800 psi. Oxygen pressure was in normal range (above 1400 psi) on preflight in atl. There were 3 pilots and 1 cockpit jump seat rider. Crew determined that loss of crew oxygen pressure had been caused by oxygen flowing from first officer's oxygen mask. The 'emergency on' position on the oxygen mask control panel was found to have been inadvertently 'bumped' into the on position. The switch was immediately reselected to the normal position. Crew discussed potential for use of supplemental oxygen and descended to 17000 ft MSL. Captain consulted dispatch and maintenance control to evaluate additional considerations and to coordinate maintenance in dtw. Flight operated normally to dtw.

Original NASA ASRS Text

Title: B727 CREW DISCOVERS AT LEVELOFF THAT CREW OXYGEN SUPPLY HAS DECREASED TO 800 PSI.

Narrative: CREW DEPARTED ATL ATL-DTW. SHORTLY AFTER LEVELOFF IN CRUISE, SO OBSERVED CREW OXYGEN PRESSURE INDICATION OF APPROX 800 PSI. OXYGEN PRESSURE WAS IN NORMAL RANGE (ABOVE 1400 PSI) ON PREFLT IN ATL. THERE WERE 3 PLTS AND 1 COCKPIT JUMP SEAT RIDER. CREW DETERMINED THAT LOSS OF CREW OXYGEN PRESSURE HAD BEEN CAUSED BY OXYGEN FLOWING FROM FO'S OXYGEN MASK. THE 'EMER ON' POS ON THE OXYGEN MASK CTL PANEL WAS FOUND TO HAVE BEEN INADVERTENTLY 'BUMPED' INTO THE ON POS. THE SWITCH WAS IMMEDIATELY RESELECTED TO THE NORMAL POS. CREW DISCUSSED POTENTIAL FOR USE OF SUPPLEMENTAL OXYGEN AND DSNDED TO 17000 FT MSL. CAPT CONSULTED DISPATCH AND MAINT CTL TO EVALUATE ADDITIONAL CONSIDERATIONS AND TO COORDINATE MAINT IN DTW. FLT OPERATED NORMALLY TO DTW.

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.