Narrative:

Challenger CL601-3A, FL370, en route apa to hpn, while performing periodic overhead panel check, discovered the #3 hydraulic system quantity at 5%. System pressure was 2800 psi with 3A pump on. Turned on 3B pump. Unable to develop pump output pressure. Confirmed lack of hydraulic fluid. Must have discovered low quantity just after loss began. 3A pump maintained adequate pressure for 5 mins. Called maintenance, discussed problem and possible diversion. Our discussion of WX at hpn resulted in diverting to atw (20-30 mins away). Advised ZAU we needed to divert to atw, that 1 of our 3 hydraulic system had failed, no emergency declaration, requested emergency equipment standing by for precaution. While diverting, priority handling was not requested or provided. Following checklist procedures, gear extended by alternate method. Nosewheel steering and inboard brakes were not available. Everything worked as in simulation training. Landing was uneventful. Callback conversation with reporter revealed the following information: the reporter stated the #3 hydraulic system loss of pressure and quantity was caused by a failed seal in the #3B electric motor driven pump.

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Original NASA ASRS Text

Title: A CHALLENGER 601-3A IN CRUISE AT FL370 DIVERTED DUE TO LOSS OF THE #3 MAIN HYD SYS CAUSED BY A FAILED #3B ELECTRIC MOTOR DRIVEN PUMP SEAL.

Narrative: CHALLENGER CL601-3A, FL370, ENRTE APA TO HPN, WHILE PERFORMING PERIODIC OVERHEAD PANEL CHK, DISCOVERED THE #3 HYD SYS QUANTITY AT 5%. SYS PRESSURE WAS 2800 PSI WITH 3A PUMP ON. TURNED ON 3B PUMP. UNABLE TO DEVELOP PUMP OUTPUT PRESSURE. CONFIRMED LACK OF HYD FLUID. MUST HAVE DISCOVERED LOW QUANTITY JUST AFTER LOSS BEGAN. 3A PUMP MAINTAINED ADEQUATE PRESSURE FOR 5 MINS. CALLED MAINT, DISCUSSED PROB AND POSSIBLE DIVERSION. OUR DISCUSSION OF WX AT HPN RESULTED IN DIVERTING TO ATW (20-30 MINS AWAY). ADVISED ZAU WE NEEDED TO DIVERT TO ATW, THAT 1 OF OUR 3 HYD SYS HAD FAILED, NO EMER DECLARATION, REQUESTED EMER EQUIP STANDING BY FOR PRECAUTION. WHILE DIVERTING, PRIORITY HANDLING WAS NOT REQUESTED OR PROVIDED. FOLLOWING CHKLIST PROCS, GEAR EXTENDED BY ALTERNATE METHOD. NOSEWHEEL STEERING AND INBOARD BRAKES WERE NOT AVAILABLE. EVERYTHING WORKED AS IN SIMULATION TRAINING. LNDG WAS UNEVENTFUL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE #3 HYD SYS LOSS OF PRESSURE AND QUANTITY WAS CAUSED BY A FAILED SEAL IN THE #3B ELECTRIC MOTOR DRIVEN PUMP.

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.