Narrative:

Aircraft type CL65. On earlier flight, had to defer AC generator idg-2 and thus disconnect idg. So far no problem. On a subsequent flight we had a failure of hydraulic pump #3A. Deferral requires that all remaining hydraulic pumps be operational. Our control asked if the other pumps were working. I advised yes at the gate, but stressed to them that in-flight the hydraulic pump 1B would not be operational (due to system logic). They advised that since the pump (1B) worked on the ground that we could defer pump 3A (main system) with an idg inoperative. Once in-flight we turned on pump 1B and it was not operational (system logic). Called maintenance, was advised that we should return. Suggest that MEL deferral for hydraulic failure, specifically state that both idg's be operational.

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Original NASA ASRS Text

Title: CL65 FLC RETURNED TO THE ARPT DUE TO AN INOP HYD PUMP.

Narrative: ACFT TYPE CL65. ON EARLIER FLT, HAD TO DEFER AC GENERATOR IDG-2 AND THUS DISCONNECT IDG. SO FAR NO PROB. ON A SUBSEQUENT FLT WE HAD A FAILURE OF HYD PUMP #3A. DEFERRAL REQUIRES THAT ALL REMAINING HYD PUMPS BE OPERATIONAL. OUR CTL ASKED IF THE OTHER PUMPS WERE WORKING. I ADVISED YES AT THE GATE, BUT STRESSED TO THEM THAT INFLT THE HYD PUMP 1B WOULD NOT BE OPERATIONAL (DUE TO SYS LOGIC). THEY ADVISED THAT SINCE THE PUMP (1B) WORKED ON THE GND THAT WE COULD DEFER PUMP 3A (MAIN SYS) WITH AN IDG INOP. ONCE INFLT WE TURNED ON PUMP 1B AND IT WAS NOT OPERATIONAL (SYS LOGIC). CALLED MAINT, WAS ADVISED THAT WE SHOULD RETURN. SUGGEST THAT MEL DEFERRAL FOR HYD FAILURE, SPECIFICALLY STATE THAT BOTH IDG'S BE OPERATIONAL.

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.