Narrative:

When first officer and I got to the cockpit; there was a placard on the pedestal; saying mechanics were working on hydraulics and not to operate the hydraulic system. First officer called maintenance twice to see what was going on. They said they were working on leak on the right side. It was also very hot on the airplane (88-90 degrees) as there was no external air connected. I called ramp twice requesting air; to no avail. I called them one more time to say that we would be starting the APU shortly; if we didn't get the external. We didn't; so I started the APU (it was now boarding time). A few mins later; a mechanic came rushing up asking why we had started the APU while somebody was working on the hydraulic leak. Eventually a lead mechanic and supervisor came up asking us the same thing. Evidently the APU had pressurized the hydraulic system; causing all hydraulic fluid of the center system to squirt out. We replied that the placard said not to operate the hydraulic system; but didn't say anything about the APU. The supervisor made it sound like a very serious event; so my question to him was; that if this was so serious; why then was there no note saying not to operate the APU and why did nobody from either ramp or maintenance say anything when it was clear for about 10-15 mins (from the numerous times we called them) that we were about to start the APU? Leak was eventually fixed and the rest of the flight was uneventful.

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Original NASA ASRS Text

Title: A B767-300 AT GATE WITH MAINT WORKING A HYD LEAK THE WAITING CREW RPTED A WARM CABIN. STARTED APU WHICH PRESSURIZED HYD RESERVOIRS. CREATED PROB WITH TECHNICIANS WORKING LEAK.

Narrative: WHEN FO AND I GOT TO THE COCKPIT; THERE WAS A PLACARD ON THE PEDESTAL; SAYING MECHS WERE WORKING ON HYDS AND NOT TO OPERATE THE HYD SYS. FO CALLED MAINT TWICE TO SEE WHAT WAS GOING ON. THEY SAID THEY WERE WORKING ON LEAK ON THE R SIDE. IT WAS ALSO VERY HOT ON THE AIRPLANE (88-90 DEGS) AS THERE WAS NO EXTERNAL AIR CONNECTED. I CALLED RAMP TWICE REQUESTING AIR; TO NO AVAIL. I CALLED THEM ONE MORE TIME TO SAY THAT WE WOULD BE STARTING THE APU SHORTLY; IF WE DIDN'T GET THE EXTERNAL. WE DIDN'T; SO I STARTED THE APU (IT WAS NOW BOARDING TIME). A FEW MINS LATER; A MECH CAME RUSHING UP ASKING WHY WE HAD STARTED THE APU WHILE SOMEBODY WAS WORKING ON THE HYD LEAK. EVENTUALLY A LEAD MECH AND SUPVR CAME UP ASKING US THE SAME THING. EVIDENTLY THE APU HAD PRESSURIZED THE HYD SYS; CAUSING ALL HYD FLUID OF THE CTR SYS TO SQUIRT OUT. WE REPLIED THAT THE PLACARD SAID NOT TO OPERATE THE HYD SYS; BUT DIDN'T SAY ANYTHING ABOUT THE APU. THE SUPVR MADE IT SOUND LIKE A VERY SERIOUS EVENT; SO MY QUESTION TO HIM WAS; THAT IF THIS WAS SO SERIOUS; WHY THEN WAS THERE NO NOTE SAYING NOT TO OPERATE THE APU AND WHY DID NOBODY FROM EITHER RAMP OR MAINT SAY ANYTHING WHEN IT WAS CLR FOR ABOUT 10-15 MINS (FROM THE NUMEROUS TIMES WE CALLED THEM) THAT WE WERE ABOUT TO START THE APU? LEAK WAS EVENTUALLY FIXED AND THE REST OF THE FLT WAS UNEVENTFUL.

Data retrieved from NASA's ASRS site as of January 2009 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.