Date: 201603
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: APU
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Workload; Physiological - Other; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: Aircraft Aircraft Damaged; Flight Crew Took Evasive Action; General Maintenance Action; General Release Refused / Aircraft Not Accepted; General Evacuated
Contributing factors: Weather; Human Factors; Aircraft; Company Policy; Procedure
Primary problem: Aircraft

Narrative: Preparing to depart; running late due to weather and ATC delays; the aircraft got toasty quickly as ramp had pulled the air without giving us a signal; per usual; in non-compliance with procedure. We started the APU; waited one minute; and put the right bleed on high cold to try to stop the rising cabin temperature. Immediately there was a faint; but noticeable smell of burnt oil or something in the cockpit. First Officer (FO) asked if I smelled it and as I responded I saw smoke drifting by us outside my window; and then smoke in the cockpit almost immediately after.I told FO we needed to get the people off now; looked back to tell the A Flight Attendant (FA) to deplane everyone through the main entry/jetway; and saw smoke filling the back of the aircraft. We turned off the pack and bleed and before we could kill the APU it died; leaving us with no AC power; and just the battery. This all transpired in just a couple of seconds. About that time the aft smoke alarm sounded; followed by the forward alarm. No fire light indication was present. I called ground on VHF1; notified them of the situation and asked them to roll the fire trucks in case there was a fire.I then tuned Operations into VHF1; notified Operations; and got up to see what I could do to help in the cabin. The evacuation was going well there; so I asked FO to take care of things in the aircraft while I go see what the status of the fire trucks was; and what exterior situation was. No Passengers were showing signs of effects from smoke. They all left their belongings and moved quickly off of the aircraft. Fire and rescue personnel met me in the jetway and told me that there was no fire; but a lot of oil leaking from the tail. I confirmed that there was a large puddle of oil below the APU; with more dripping fairly quickly onto the ground.Maintenance came up and confirmed that the APU oil had leaked; causing the smoke; and said he would MEL the APU and get us on our way. I had him open the APU door and inspect for fire damage while FO and I discussed whether or not we liked the plan. Ground Operations asked if I'd like another aircraft; I said I would; and we were moved to another aircraft. Dispatch and Chief Pilot on call were contacted and briefed on all of the above. A log book entry was made.The FAs were removed and replaced. FO and I agreed that we were okay; swapped aircrafts and continued to our destination. The FAs and FO all did an excellent job; and were very professional and calm.




Synopsis: A B737 Captain reported after boarding and staring the APU; APU leaked oil into the air conditioning system resulting in cabin smoke and an evacuation at the gate.