Smoke smell in rear lavatories. Flight returned to and landed at lax.

Attributes
ACN	139550
Time
Date	199003
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : lax
State Reference	CA
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lax
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : sid enroute : pacific
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp pilot : commercial
Experience	flight time total : 9000
ASRS Report	139550
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Aft lav smoke detectors (widebody transport) all sounded. Second officer reported smoke smell and odor. Emergency declared, fuel dumped and return made to lax. Callback conversation with reporter revealed the following: second officer reported the smell was electrical but post-flight inspection by maintenance revealed a failed check valve that allowed hot air to enter the lav venting system. Airline is inspecting all the aircraft of this make model.

Original NASA ASRS Text

Title: SMOKE SMELL IN REAR LAVATORIES. FLT RETURNED TO AND LANDED AT LAX.

Narrative: AFT LAV SMOKE DETECTORS (WDB) ALL SOUNDED. S/O REPORTED SMOKE SMELL AND ODOR. EMER DECLARED, FUEL DUMPED AND RETURN MADE TO LAX. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: S/O REPORTED THE SMELL WAS ELECTRICAL BUT POST-FLT INSPECTION BY MAINT REVEALED A FAILED CHECK VALVE THAT ALLOWED HOT AIR TO ENTER THE LAV VENTING SYSTEM. AIRLINE IS INSPECTING ALL THE ACFT OF THIS MAKE MODEL.

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.