Flight crew of an medium large transport descended to a lower altitude in response to the inadvertent drop and use of passenger oxygen during leveloff to high cruise altitude. The flight crew subsequently climbed from assigned altitude in an effort to avoid turbulence without clearance. Diversion to an alternate was made for fuel.

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Attributes
ACN	334436
Time
Date	199604
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : yyc
State Reference	AB
Altitude	msl bound lower : 25000 msl bound upper : 33000
Aircraft 1
Controlling Facilities	artcc : czeg tower : dfw
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	334436
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other other : unspecified
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

Oxygen mask deployment and diversion. In the process of leveling at FL330 the flight attendants called to report that all oxygen masks had been deployed. We checked the pressurization system and all indications were normal. I told the flight attendant on intercom that everything was normal and not to use oxygen. Apparently a deadheading flight attendant in flight crew thought she was feeling some dizziness and started using oxygen. By the time I made the PA not to use the oxygen, many of the passenger had already activated the cylinders. Once the oxygen was activated and used we had to descend to FL250 per the flight manual. After consultation with dispatch, we diverted to denver for fuel. One added note I will include, was a climb back up to FL260 because of moderate turbulence.

Original NASA ASRS Text

Title: FLC OF AN MLG DSNDED TO A LOWER ALT IN RESPONSE TO THE INADVERTENT DROP AND USE OF PAX OXYGEN DURING LEVELOFF TO HIGH CRUISE ALT. THE FLC SUBSEQUENTLY CLBED FROM ASSIGNED ALT IN AN EFFORT TO AVOID TURB WITHOUT CLRNC. DIVERSION TO AN ALTERNATE WAS MADE FOR FUEL.

Narrative: OXYGEN MASK DEPLOYMENT AND DIVERSION. IN THE PROCESS OF LEVELING AT FL330 THE FLT ATTENDANTS CALLED TO RPT THAT ALL OXYGEN MASKS HAD BEEN DEPLOYED. WE CHKED THE PRESSURIZATION SYS AND ALL INDICATIONS WERE NORMAL. I TOLD THE FLT ATTENDANT ON INTERCOM THAT EVERYTHING WAS NORMAL AND NOT TO USE OXYGEN. APPARENTLY A DEADHEADING FLT ATTENDANT IN FLC THOUGHT SHE WAS FEELING SOME DIZZINESS AND STARTED USING OXYGEN. BY THE TIME I MADE THE PA NOT TO USE THE OXYGEN, MANY OF THE PAX HAD ALREADY ACTIVATED THE CYLINDERS. ONCE THE OXYGEN WAS ACTIVATED AND USED WE HAD TO DSND TO FL250 PER THE FLT MANUAL. AFTER CONSULTATION WITH DISPATCH, WE DIVERTED TO DENVER FOR FUEL. ONE ADDED NOTE I WILL INCLUDE, WAS A CLB BACK UP TO FL260 BECAUSE OF MODERATE TURB.

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.