A B737-700 was dispatched after the crew oxygen bottle was replaced. Bottle valve was opened and sys...

Attributes
ACN	725729
Time
Date	200701
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Function	maintenance : technician
Qualification	technician : airframe technician : powerplant
ASRS Report	725729
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	other other
Factors
Maintenance	performance deficiency : testing performance deficiency : scheduled maintenance performance deficiency : non compliance with legal requirements performance deficiency : installation
Supplementary
Problem Areas	Maintenance Human Performance Environmental Factor Aircraft Company
Primary Problem	Aircraft
Situations
Publication	Maint Manual Chapter 35

Narrative:

This was my first time changing crew oxygen bottle on a B-700 aircraft. When I installed the bottle I must have been confused by looking at the valve from the top (B-300 aircraft is other orientation). I know I opened the valve enough to have pressure in the line; as I checked the gauge and did the mask test; but I must have not noticed the slow recovery on the gauge. I'm pretty sure that I fully closed the valve and opened it a 1/4 turn; instead of fully opening valve and closing 1/4 turn. I certainly will not make the same mistake in the future. Callback conversation with reporter revealed the following information: the bottle was replaced and the valve was opened and the oxygen flow was tested using 100% flow looking/watching for a pressure drop. Callback conversation with reporter revealed the following information: the reporter was familiar with the composite bottle problems of the valve stopping before being fully opened and believed the valve was fully opened. The procedure with the valve problem is to open the valve till it stops then use a 'limited' force turning the valve to the open position. The reporter believes the problem may also be in testing the system as the mask test may only be testing the oxygen in the line. The reporter's procedure is to use 100% lever and wait for 10-15 seconds and watch the gauge for recovery during the test.

Original NASA ASRS Text

Title: A B737-700 WAS DISPATCHED AFTER THE CREW OXYGEN BOTTLE WAS REPLACED. BOTTLE VALVE WAS OPENED AND SYS TESTED. LATER RPTED VALVE FOUND NOT FULLY OPENED. BOTTLE WAS OF COMPOSITE TYPE.

Narrative: THIS WAS MY FIRST TIME CHANGING CREW OXYGEN BOTTLE ON A B-700 ACFT. WHEN I INSTALLED THE BOTTLE I MUST HAVE BEEN CONFUSED BY LOOKING AT THE VALVE FROM THE TOP (B-300 ACFT IS OTHER ORIENTATION). I KNOW I OPENED THE VALVE ENOUGH TO HAVE PRESSURE IN THE LINE; AS I CHKED THE GAUGE AND DID THE MASK TEST; BUT I MUST HAVE NOT NOTICED THE SLOW RECOVERY ON THE GAUGE. I'M PRETTY SURE THAT I FULLY CLOSED THE VALVE AND OPENED IT A 1/4 TURN; INSTEAD OF FULLY OPENING VALVE AND CLOSING 1/4 TURN. I CERTAINLY WILL NOT MAKE THE SAME MISTAKE IN THE FUTURE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE BOTTLE WAS REPLACED AND THE VALVE WAS OPENED AND THE OXYGEN FLOW WAS TESTED USING 100% FLOW LOOKING/WATCHING FOR A PRESSURE DROP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS FAMILIAR WITH THE COMPOSITE BOTTLE PROBS OF THE VALVE STOPPING BEFORE BEING FULLY OPENED AND BELIEVED THE VALVE WAS FULLY OPENED. THE PROC WITH THE VALVE PROB IS TO OPEN THE VALVE TILL IT STOPS THEN USE A 'LIMITED' FORCE TURNING THE VALVE TO THE OPEN POS. THE RPTR BELIEVES THE PROB MAY ALSO BE IN TESTING THE SYS AS THE MASK TEST MAY ONLY BE TESTING THE OXYGEN IN THE LINE. THE RPTR'S PROC IS TO USE 100% LEVER AND WAIT FOR 10-15 SECONDS AND WATCH THE GAUGE FOR RECOVERY DURING THE TEST.

Data retrieved from NASA's ASRS site as of January 2009 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.

A B737-700 was dispatched after the crew oxygen bottle was replaced. Bottle valve was opened and system tested. Later reported valve found not fully opened. Bottle was of composite type.