Narrative:

Doors closed in preparation for pushback in mex and the cockpit and cabin began to fill with a white vapor which had an unusual odor to it, but did not smell of smoke. The right pack was running off of the APU bleed. I turned the right pack off and called to the flight attendants to see if they could spot a source. One of the flight attendants thought the vapor was coming from the vents, but had stopped when I shut off the pack. I also called the ground crew and asked if they could see anything, to which they said 'no.' as we were out on the pad and the people mover had left, I had the ground crew bring the stairs up to the plane at 'L1.' I also had the cabin crew open all doors to vent the cabin. Upon investigating on the outside of the aircraft, I found a trail of oil running from the APU accessory cooling exhaust to about 1/2 down the tailcone. Returning to the cockpit to secure the APU, I noticed the APU low oil quantity annunciator had illuminated while I was out of my seat. After consulting with phx maintenance and having air carrier maintenance open the APU bay to check the APU, it was determined that the oil had been drawn into the APU bleed air supply and thus into the pack. I used a ground air cart to supply pneumatic pressure and ran the packs to clear and operations check for approximately 5 mins with maintenance on board. All checked normal. Received a dpi (deferred placard) for the APU and then departed mex normally.

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Original NASA ASRS Text

Title: A B737-300 PARKED PRIOR TO DEP HAD THE CABIN FILL WITH WHITE VAPOR WITH AN UNUSUAL ODOR CAUSED BY APU OIL LEAKING INTO THE APU PNEUMATICS SUPPLYING THE AIR CONDITIONING PACK.

Narrative: DOORS CLOSED IN PREPARATION FOR PUSHBACK IN MEX AND THE COCKPIT AND CABIN BEGAN TO FILL WITH A WHITE VAPOR WHICH HAD AN UNUSUAL ODOR TO IT, BUT DID NOT SMELL OF SMOKE. THE R PACK WAS RUNNING OFF OF THE APU BLEED. I TURNED THE R PACK OFF AND CALLED TO THE FLT ATTENDANTS TO SEE IF THEY COULD SPOT A SOURCE. ONE OF THE FLT ATTENDANTS THOUGHT THE VAPOR WAS COMING FROM THE VENTS, BUT HAD STOPPED WHEN I SHUT OFF THE PACK. I ALSO CALLED THE GND CREW AND ASKED IF THEY COULD SEE ANYTHING, TO WHICH THEY SAID 'NO.' AS WE WERE OUT ON THE PAD AND THE PEOPLE MOVER HAD LEFT, I HAD THE GND CREW BRING THE STAIRS UP TO THE PLANE AT 'L1.' I ALSO HAD THE CABIN CREW OPEN ALL DOORS TO VENT THE CABIN. UPON INVESTIGATING ON THE OUTSIDE OF THE ACFT, I FOUND A TRAIL OF OIL RUNNING FROM THE APU ACCESSORY COOLING EXHAUST TO ABOUT 1/2 DOWN THE TAILCONE. RETURNING TO THE COCKPIT TO SECURE THE APU, I NOTICED THE APU LOW OIL QUANTITY ANNUNCIATOR HAD ILLUMINATED WHILE I WAS OUT OF MY SEAT. AFTER CONSULTING WITH PHX MAINT AND HAVING ACR MAINT OPEN THE APU BAY TO CHK THE APU, IT WAS DETERMINED THAT THE OIL HAD BEEN DRAWN INTO THE APU BLEED AIR SUPPLY AND THUS INTO THE PACK. I USED A GND AIR CART TO SUPPLY PNEUMATIC PRESSURE AND RAN THE PACKS TO CLR AND OPS CHK FOR APPROX 5 MINS WITH MAINT ON BOARD. ALL CHKED NORMAL. RECEIVED A DPI (DEFERRED PLACARD) FOR THE APU AND THEN DEPARTED MEX NORMALLY.

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.