B727 crew had the oxygen quantity go to zero.

Attributes
ACN	446941
Time
Date	199908
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zma.artcc
Altitude	msl single value : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zma.artcc tower : bos.tower
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 0 flight time total : 4500 flight time type : 0
ASRS Report	446941
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure non adherence : far non adherence : company policies
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : detected after the fact none taken : anomaly accepted
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Captain left the aircraft en route to aruba to use the restroom. The first officer put his oxygen on then later first officer went to do same (approximately 30 mins) later. Captain went on oxygen and could not breathe. He commented to me (the flight engineer). We checked the oxygen level and saw it at 0 psi. Looked over at the first officer's oxygen mask and found the regulator on emergency. We assumed that was the cause of the oxygen depletion. Myself and the captain discussed the situation and decided that we had some oxygen in the fire fighter's mask and oxygen in the back for medical use. Due to low fuel at approximately 12000 pounds, getting below 10000 ft was not practical so he decided to stay at altitude and continue the flight. When the first officer returned he informed him of the situation. We did have an FAA inspector on board the aircraft who was giving the flight attendants an evaluation. We landed in aruba uneventfully. The flight attendants were not informed of the situation and not too long after the discovery, we started a descent to a lower altitude towards landing.

Original NASA ASRS Text

Title: B727 CREW HAD THE OXYGEN QUANTITY GO TO ZERO.

Narrative: CAPT LEFT THE ACFT ENRTE TO ARUBA TO USE THE RESTROOM. THE FO PUT HIS OXYGEN ON THEN LATER FO WENT TO DO SAME (APPROX 30 MINS) LATER. CAPT WENT ON OXYGEN AND COULD NOT BREATHE. HE COMMENTED TO ME (THE FE). WE CHKED THE OXYGEN LEVEL AND SAW IT AT 0 PSI. LOOKED OVER AT THE FO'S OXYGEN MASK AND FOUND THE REGULATOR ON EMER. WE ASSUMED THAT WAS THE CAUSE OF THE OXYGEN DEPLETION. MYSELF AND THE CAPT DISCUSSED THE SIT AND DECIDED THAT WE HAD SOME OXYGEN IN THE FIRE FIGHTER'S MASK AND OXYGEN IN THE BACK FOR MEDICAL USE. DUE TO LOW FUEL AT APPROX 12000 LBS, GETTING BELOW 10000 FT WAS NOT PRACTICAL SO HE DECIDED TO STAY AT ALT AND CONTINUE THE FLT. WHEN THE FO RETURNED HE INFORMED HIM OF THE SIT. WE DID HAVE AN FAA INSPECTOR ON BOARD THE ACFT WHO WAS GIVING THE FLT ATTENDANTS AN EVALUATION. WE LANDED IN ARUBA UNEVENTFULLY. THE FLT ATTENDANTS WERE NOT INFORMED OF THE SIT AND NOT TOO LONG AFTER THE DISCOVERY, WE STARTED A DSCNT TO A LOWER ALT TOWARDS LNDG.

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.