Narrative:

The weather conditions at our departure airport were a steady rain; temperature about 40F; and a strong wind out of the west. During our preflight and approximately 15 minutes prior to load complete; the flight crew and both jumpseaters notice a strong 'musty' / 'wet sock' smell. I have experienced this smell before typically in wet conditions with the packs running. No visible smoke was present. The strength of the odor would increase and decrease during the remainder of the load process. Once the airplane was loaded and we obtained clearance from ramp control; we began the engine start process. Engine #3 was started normally. During the start sequence for the #1 engine I noticed that APU oil quantity was '0.5' and boxed in yellow. I made a comment to the captain along the lines of 'it looks like the oil quantity in the APU is below normal' and 'we'll have to have the destination airport maintenance guys take a look.' approximately 15 seconds later; after the #1 start valve had closed; the APU did an auto-shutdown. No warnings or additional odors were associated with the shutdown; just the normal 'APU automatic shutdown' message displayed on the ead. Since the start valve had closed and the APU was no longer needed for the #1 engine; we continued with the engine start. We informed the mechanic; called flight control for a deferral; and did the appropriate paperwork in the logbook. When then proceeded to start engine #2 using the 'crossbleed start' procedures from the aom. It was my leg and both taxi and takeoff were uneventful with what I would describe as the 'musty' odor present but not as strong as it was during loading. Once we leveled off at an intermediate altitude of fl 320; the captain stated that I had control of the airplane and the radios and he was going to double check the logbook and make sure we did all the paperwork appropriately. While at fl 320 the odor appeared to increase. We both commented that we thought the smell should have cleared out by now. We both pulled out our flashlights; opened the air vent on the side console; and shined the flashlight at the vent looking for smoke. Smoke was not coming out of the vent but it was very obvious that there was some sort of smoke / particle in the air when looking at the light beam. We then received clearance to fl 360 where we eventually leveled off. After approximately 3 - 5 minutes the level 3 'crg fire lwr aft' message illuminated with the associated aural tones. I immediately suggested we proceed a nearby airport which was approximately 90 - 100 miles on the nose. The captain took control of the airplane and we immediately accomplished the memory item associated with the crg fire lwr aft by pushing the flashing cargo fire agent discharge switch. I declared an emergency with center; asked for lower; and donned the oxygen mask but I am not sure of the order of those three items. I yelled at the jumpseaters to come up front and we started a descent. I told the jumpseaters we had a cargo fire; they donned their masks; and I got out the QRH. While coordinating with center; the captain and I worked through the checklist in the QRH. We completed the first three items in the checklist; verified that the 'crg flo aft disag' message was not displayed; and verified that the discharge low light was illuminated. I passed my approach plate book to the jumpseater and asked him to get out the new destination approach plates for me. Center cleared us direct to the marker for runway 30. I confirmed with the captain that we would be doing an emergency evacuation and got out the checklist in the QRH and read it out loud so all 4 of us could get a plan in our minds. We attempted to keep the speed up as much as possible throughout the descent and approach. I believe approximately 4 - 5 minutes after the bottle discharged the level 3 message went away. We did an autoland to 30; took a high speed exit to the right; and accomplished the emergency evacuation checklist from top to bottom. The captain directed one of the jumpseaters to blow the slide. I was the first one down the slide followed by the two jumpseaters and the captain. The captain had briefed that we would meet in the front of the airplane so we all 4 congregated off to the left; front side of the jet and got out of the way of the fire fighting crews.

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Original NASA ASRS Text

Title: A MD11's APU bearing failure during preflight allowed oil into the air conditioning system causing a wet sock smell; subsequently the APU did a low oil auto shutdown. During flight the CRG FIRE LWR AFT message alerted so an emergency was declared; the QRH completed and the flight diverted to a nearby airport where an emergency evacuation followed.

Narrative: The weather conditions at our departure airport were a steady rain; temperature about 40F; and a strong wind out of the west. During our preflight and approximately 15 minutes prior to load complete; the flight crew and both jumpseaters notice a strong 'musty' / 'wet sock' smell. I have experienced this smell before typically in wet conditions with the packs running. No visible smoke was present. The strength of the odor would increase and decrease during the remainder of the load process. Once the airplane was loaded and we obtained clearance from Ramp Control; we began the engine start process. Engine #3 was started normally. During the start sequence for the #1 engine I noticed that APU oil quantity was '0.5' and boxed in yellow. I made a comment to the Captain along the lines of 'It looks like the oil quantity in the APU is below normal' and 'we'll have to have the destination airport Maintenance guys take a look.' Approximately 15 seconds later; after the #1 start valve had closed; the APU did an auto-shutdown. No warnings or additional odors were associated with the shutdown; just the normal 'APU AUTO SHUTDOWN' message displayed on the EAD. Since the start valve had closed and the APU was no longer needed for the #1 engine; we continued with the engine start. We informed the Mechanic; called Flight Control for a deferral; and did the appropriate paperwork in the logbook. When then proceeded to start engine #2 using the 'Crossbleed Start' procedures from the AOM. It was my leg and both Taxi and Takeoff were uneventful with what I would describe as the 'musty' odor present but not as strong as it was during loading. Once we leveled off at an intermediate altitude of FL 320; the Captain stated that I had control of the airplane and the radios and he was going to double check the logbook and make sure we did all the paperwork appropriately. While at FL 320 the odor appeared to increase. We both commented that we thought the smell should have cleared out by now. We both pulled out our flashlights; opened the air vent on the side console; and shined the flashlight at the vent looking for smoke. Smoke was not coming out of the vent but it was very obvious that there was some sort of smoke / particle in the air when looking at the light beam. We then received clearance to FL 360 where we eventually leveled off. After approximately 3 - 5 minutes the Level 3 'CRG FIRE LWR AFT' message illuminated with the associated aural tones. I immediately suggested we proceed a nearby airport which was approximately 90 - 100 miles on the nose. The Captain took control of the airplane and we immediately accomplished the Memory Item associated with the CRG FIRE LWR AFT by pushing the Flashing Cargo Fire Agent Discharge switch. I declared an emergency with Center; asked for lower; and donned the oxygen mask but I am not sure of the order of those three items. I yelled at the jumpseaters to come up front and we started a descent. I told the jumpseaters we had a cargo fire; they donned their masks; and I got out the QRH. While coordinating with Center; the Captain and I worked through the checklist in the QRH. We completed the first three items in the checklist; verified that the 'CRG FLO AFT DISAG' message was not displayed; and verified that the Discharge Low Light was illuminated. I passed my approach plate book to the jumpseater and asked him to get out the new destination approach plates for me. Center cleared us direct to the marker for Runway 30. I confirmed with the Captain that we would be doing an Emergency Evacuation and got out the checklist in the QRH and read it out loud so all 4 of us could get a plan in our minds. We attempted to keep the speed up as much as possible throughout the descent and approach. I believe approximately 4 - 5 minutes after the bottle discharged the Level 3 message went away. We did an autoland to 30; took a high speed exit to the right; and accomplished the Emergency Evacuation checklist from top to bottom. The Captain directed one of the jumpseaters to blow the slide. I was the first one down the slide followed by the two jumpseaters and the Captain. The Captain had briefed that we would meet in the front of the airplane so we all 4 congregated off to the left; front side of the jet and got out of the way of the fire fighting crews.

Data retrieved from NASA's ASRS site as of April 2012 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.