DC10-40 crew has #3 hydraulic system failure and returns to land.

Attributes
ACN	467350
Time
Date	200003
Day	Mon
Local Time Of Day	0601 To 1200
Place
State Reference	ND
Altitude	msl single value : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	DC-10 40
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Route In Use	enroute airway : j36.airway
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : multi engine pilot : instrument pilot : flight engineer pilot : cfi pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 11200 flight time type : 3200
ASRS Report	467350
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 13000 flight time type : 600
ASRS Report	466884
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : temp/press ind. other flight crewa other flight crewb other flight crewb
Resolutory Action	flight crew : diverted to another airport flight crew : declared emergency flight crew : landed in emergency condition
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

After leveloff at FL350 (approximately 30 mins into flight) the #3 engine right hydraulic pump temperature high light illuminated with the pump in the off position. System temperature indicated 58 degrees. System pressure on #3 hydraulic initially indicated normal at 3000 psi and was being driven by the left hydraulic pump. System pressure then began to increase to 4000 psi and the #3 engine left hydraulic pump was turned off. Cockpit operating procedures for both temperature high light and high pressure were completed and a call to company maintenance was initiated. System quantity was normal and a slight decrease in system temperature was observed. It was noted that the #3 system temperature began to increase at a slow rate and then a sudden loss of all hydraulic fluid in #3 system was observed. Cockpit operating procedures were completed for a loss of all fluid to the #3 system. Flight returned to msp with landing and approach normal for the procedures. Aircraft stopped on runway and tugged to the gate. Supplemental information from acn 467061: on initial #3 engine start, the right hydraulic pump lagged behind the left one, but operated normally, well within all limits. Callback conversation with reporter acn 467350 revealed the following information: reporter said that the right pump for #3 hydraulic system is normally off during cruise. This led to confusion over the overheat indication with the pump off. It was found after landing to have been a failed pump.

Original NASA ASRS Text

Title: DC10-40 CREW HAS #3 HYD SYS FAILURE AND RETURNS TO LAND.

Narrative: AFTER LEVELOFF AT FL350 (APPROX 30 MINS INTO FLT) THE #3 ENG R HYD PUMP TEMP HIGH LIGHT ILLUMINATED WITH THE PUMP IN THE OFF POS. SYS TEMP INDICATED 58 DEGS. SYS PRESSURE ON #3 HYD INITIALLY INDICATED NORMAL AT 3000 PSI AND WAS BEING DRIVEN BY THE L HYD PUMP. SYS PRESSURE THEN BEGAN TO INCREASE TO 4000 PSI AND THE #3 ENG L HYD PUMP WAS TURNED OFF. COCKPIT OPERATING PROCS FOR BOTH TEMP HIGH LIGHT AND HIGH PRESSURE WERE COMPLETED AND A CALL TO COMPANY MAINT WAS INITIATED. SYS QUANTITY WAS NORMAL AND A SLIGHT DECREASE IN SYS TEMP WAS OBSERVED. IT WAS NOTED THAT THE #3 SYS TEMP BEGAN TO INCREASE AT A SLOW RATE AND THEN A SUDDEN LOSS OF ALL HYD FLUID IN #3 SYS WAS OBSERVED. COCKPIT OPERATING PROCS WERE COMPLETED FOR A LOSS OF ALL FLUID TO THE #3 SYS. FLT RETURNED TO MSP WITH LNDG AND APCH NORMAL FOR THE PROCS. ACFT STOPPED ON RWY AND TUGGED TO THE GATE. SUPPLEMENTAL INFO FROM ACN 467061: ON INITIAL #3 ENG START, THE R HYD PUMP LAGGED BEHIND THE L ONE, BUT OPERATED NORMALLY, WELL WITHIN ALL LIMITS. CALLBACK CONVERSATION WITH RPTR ACN 467350 REVEALED THE FOLLOWING INFO: RPTR SAID THAT THE R PUMP FOR #3 HYD SYS IS NORMALLY OFF DURING CRUISE. THIS LED TO CONFUSION OVER THE OVERHEAT INDICATION WITH THE PUMP OFF. IT WAS FOUND AFTER LNDG TO HAVE BEEN A FAILED 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.