Narrative:

I was the captain on an medium large transport flight from sfo to sna. We were making a visibility approach to the airport and had fully configured for landing when, at approximately 1400', the master caution light illuminated and the left hydraulic pressure low light was on. The gauges showed both the pressure and the quantity to be down to almost 0 on the left system. The first officer asked if I wanted to go around and run the abnormal checklist. I told him no, that I wanted to land since we were already fully configured and we quickly reviewed the items on the left system and decided that only the inboard flight spoilers would be totally inoperative due to the failure. That was no problem, since the winds were rather light and right down the runway. Everything else on the left system was either pwred by the right system or by an accumulator. Another reason I was reluctant to go around was because of the high density of light airplane traffic around sna on a pleasant afternoon. I didn't want to be out there driving around in the environment working on a problem and maybe waiting for the company to get back to us to go somewhere else. A normal landing was made. Once we turned off at the end of the runway, we pulled out the abnormal checklist and the only thing left to do was to turn off the left hydraulic pump and the trans pump, which we did. The checklist didn't say anything about the APU, and that was our only oversight. We cranked the APU for electrical power and air conditioning at the gate. We didn't know where the big hydraulic leak was and it turned out to be in the tail. Some hydraulic fluid must have sprayed onto the APU exhaust ducting, where it was heated and began to smoke. One source for air on the ground is from the tailcone area, and since it was so full of smoke, it didn't take long to pump a lot of it into the cabin. Just as we were pulling into the gate we noticed smoke coming out of our overhead air conditioning vents. At that same moment, the F/a in the back called to tell us that the cabin was filling with smoke and to ask what was going on. We immediately turned off both air conditioning supply switches and as we were stopping, the first officer told the people briefly what happened and that it would clear in just a moment. The smoke got thick very quickly as we pulled onto the gate--thick enough that the girls said they could not see the length of the aircraft. But as soon as we stopped, we opened both front doors and the smoke cleared very quickly. A normal and orderly passenger off-loading followed. I would estimate that it was less than 2 mins from the time we first noticed the smoke until it was fairly well cleared from the cabin. Supplemental information from acn 111047: incident could have been prevented by not cranking APU and switching to that environmental system after known hydraulic leak.

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Original NASA ASRS Text

Title: HYDRAULIC SYSTEM FLUID AND PRESSURE LOSS ON FINAL APCH. DURING TAXI-IN HYDRAULIC FLUID LEAK RESULTED IN FLUID CONTACTING HOT COMPONENT RESULTING IN SMOKE ENTERING CABIN THROUGH AIR CONDITIONING SYSTEM.

Narrative: I WAS THE CAPT ON AN MLG FLT FROM SFO TO SNA. WE WERE MAKING A VIS APCH TO THE ARPT AND HAD FULLY CONFIGURED FOR LNDG WHEN, AT APPROX 1400', THE MASTER CAUTION LIGHT ILLUMINATED AND THE LEFT HYD PRESSURE LOW LIGHT WAS ON. THE GAUGES SHOWED BOTH THE PRESSURE AND THE QUANTITY TO BE DOWN TO ALMOST 0 ON THE LEFT SYS. THE F/O ASKED IF I WANTED TO GO AROUND AND RUN THE ABNORMAL CHKLIST. I TOLD HIM NO, THAT I WANTED TO LAND SINCE WE WERE ALREADY FULLY CONFIGURED AND WE QUICKLY REVIEWED THE ITEMS ON THE LEFT SYS AND DECIDED THAT ONLY THE INBOARD FLT SPOILERS WOULD BE TOTALLY INOP DUE TO THE FAILURE. THAT WAS NO PROB, SINCE THE WINDS WERE RATHER LIGHT AND RIGHT DOWN THE RWY. EVERYTHING ELSE ON THE LEFT SYS WAS EITHER PWRED BY THE RIGHT SYS OR BY AN ACCUMULATOR. ANOTHER REASON I WAS RELUCTANT TO GO AROUND WAS BECAUSE OF THE HIGH DENSITY OF LIGHT AIRPLANE TFC AROUND SNA ON A PLEASANT AFTERNOON. I DIDN'T WANT TO BE OUT THERE DRIVING AROUND IN THE ENVIRONMENT WORKING ON A PROB AND MAYBE WAITING FOR THE COMPANY TO GET BACK TO US TO GO SOMEWHERE ELSE. A NORMAL LNDG WAS MADE. ONCE WE TURNED OFF AT THE END OF THE RWY, WE PULLED OUT THE ABNORMAL CHKLIST AND THE ONLY THING LEFT TO DO WAS TO TURN OFF THE LEFT HYD PUMP AND THE TRANS PUMP, WHICH WE DID. THE CHKLIST DIDN'T SAY ANYTHING ABOUT THE APU, AND THAT WAS OUR ONLY OVERSIGHT. WE CRANKED THE APU FOR ELECTRICAL PWR AND AIR CONDITIONING AT THE GATE. WE DIDN'T KNOW WHERE THE BIG HYD LEAK WAS AND IT TURNED OUT TO BE IN THE TAIL. SOME HYD FLUID MUST HAVE SPRAYED ONTO THE APU EXHAUST DUCTING, WHERE IT WAS HEATED AND BEGAN TO SMOKE. ONE SOURCE FOR AIR ON THE GND IS FROM THE TAILCONE AREA, AND SINCE IT WAS SO FULL OF SMOKE, IT DIDN'T TAKE LONG TO PUMP A LOT OF IT INTO THE CABIN. JUST AS WE WERE PULLING INTO THE GATE WE NOTICED SMOKE COMING OUT OF OUR OVERHEAD AIR CONDITIONING VENTS. AT THAT SAME MOMENT, THE F/A IN THE BACK CALLED TO TELL US THAT THE CABIN WAS FILLING WITH SMOKE AND TO ASK WHAT WAS GOING ON. WE IMMEDIATELY TURNED OFF BOTH AIR CONDITIONING SUPPLY SWITCHES AND AS WE WERE STOPPING, THE F/O TOLD THE PEOPLE BRIEFLY WHAT HAPPENED AND THAT IT WOULD CLEAR IN JUST A MOMENT. THE SMOKE GOT THICK VERY QUICKLY AS WE PULLED ONTO THE GATE--THICK ENOUGH THAT THE GIRLS SAID THEY COULD NOT SEE THE LENGTH OF THE ACFT. BUT AS SOON AS WE STOPPED, WE OPENED BOTH FRONT DOORS AND THE SMOKE CLRED VERY QUICKLY. A NORMAL AND ORDERLY PAX OFF-LOADING FOLLOWED. I WOULD ESTIMATE THAT IT WAS LESS THAN 2 MINS FROM THE TIME WE FIRST NOTICED THE SMOKE UNTIL IT WAS FAIRLY WELL CLRED FROM THE CABIN. SUPPLEMENTAL INFO FROM ACN 111047: INCIDENT COULD HAVE BEEN PREVENTED BY NOT CRANKING APU AND SWITCHING TO THAT ENVIRONMENTAL SYS AFTER KNOWN HYD LEAK.

Data retrieved from NASA's ASRS site as of August 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.