A level 3 cabin smoke alarm on a cargo MD11 mandates an emergency descent and diversion to phx, az.

Attributes
ACN	559703
Time
Date	200209
Day	Wed
Place
Locale Reference	airport : phx.airport
State Reference	AZ
Altitude	msl single value : 37000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zab.artcc
Operator	common carrier : air carrier
Make Model Name	MD-11
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : instrument pilot : flight engineer pilot : multi engine pilot : cfi
Experience	flight time last 90 days : 142 flight time total : 10000 flight time type : 2300
ASRS Report	559703
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical cabin event other other anomaly other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : cabin smoke alarm
Resolutory Action	controller : issued new clearance controller : provided flight assist flight crew : landed in emergency condition flight crew : diverted to another airport flight crew : declared emergency
Consequence	faa : reviewed incident with flight crew other other
Supplementary
Problem Areas	Aircraft Company Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

In cruise flight about 70 NM north phx at FL370, got level 3 cabin smoke alert. Declared an emergency and went on oxygen. Requested immediate divert to phx, completed all required checklists and procedures. Maintained 330 KTS until 8000 ft to expedite getting on ground. Lnded without incident. Callback conversation with reporter revealed the following information: the reporting PIC stated that there was no smoke or anything on board that would have produced smoke. No system problems with the aircraft. There was however, a large amount of dry ice on board that may have tripped the sensors. When asked if the system could sense the emissions from a large amount of dry ice and produce a warning as a smoke alert, the PIC said, 'yes.' company had no other explanation other than the dry ice.

Original NASA ASRS Text

Title: A LEVEL 3 CABIN SMOKE ALARM ON A CARGO MD11 MANDATES AN EMER DSCNT AND DIVERSION TO PHX, AZ.

Narrative: IN CRUISE FLT ABOUT 70 NM N PHX AT FL370, GOT LEVEL 3 CABIN SMOKE ALERT. DECLARED AN EMER AND WENT ON OXYGEN. REQUESTED IMMEDIATE DIVERT TO PHX, COMPLETED ALL REQUIRED CHKLISTS AND PROCS. MAINTAINED 330 KTS UNTIL 8000 FT TO EXPEDITE GETTING ON GND. LNDED WITHOUT INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTING PIC STATED THAT THERE WAS NO SMOKE OR ANYTHING ON BOARD THAT WOULD HAVE PRODUCED SMOKE. NO SYS PROBS WITH THE ACFT. THERE WAS HOWEVER, A LARGE AMOUNT OF DRY ICE ON BOARD THAT MAY HAVE TRIPPED THE SENSORS. WHEN ASKED IF THE SYS COULD SENSE THE EMISSIONS FROM A LARGE AMOUNT OF DRY ICE AND PRODUCE A WARNING AS A SMOKE ALERT, THE PIC SAID, 'YES.' COMPANY HAD NO OTHER EXPLANATION OTHER THAN THE DRY ICE.

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.