CL65 flight crew returned to the airport due to an inoperative hydraulic pump.

Attributes
ACN	373782
Time
Date	199707
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : cvg
State Reference	OH
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Challenger CL604
Navigation In Use	Other Other
Flight Phase	climbout : takeoff ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 210 flight time total : 16400 flight time type : 4000
ASRS Report	373782
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa other other : unspecified
Resolutory Action	none taken : detected after the fact other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
Publication	Unspecified

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.

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.