Large transport a system hydraulic failure while enroute.

Attributes
ACN	80759
Time
Date	198801
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bdf airport : dtw
State Reference	IL
Altitude	msl bound lower : 33000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 175 flight time total : 3300 flight time type : 450
ASRS Report	80759
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 5000 flight time type : 1500
ASRS Report	80757
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

We were cruising at FL330, 20 NM east of bdf, when we noticed the system a hydraulic low pressure lights illuminated. Then observed the system a quantity and pressure gauges at zero. We descended to FL250 and returned to detroit (redispatch by company due to low WX at msp) for an uneventful approach and landing. After clearing runway, the gear pins were installed and we were towed to the gate.

Original NASA ASRS Text

Title: LGT A SYSTEM HYDRAULIC FAILURE WHILE ENROUTE.

Narrative: WE WERE CRUISING AT FL330, 20 NM EAST OF BDF, WHEN WE NOTICED THE SYS A HYDRAULIC LOW PRESSURE LIGHTS ILLUMINATED. THEN OBSERVED THE SYS A QUANTITY AND PRESSURE GAUGES AT ZERO. WE DSNDED TO FL250 AND RETURNED TO DETROIT (REDISPATCH BY COMPANY DUE TO LOW WX AT MSP) FOR AN UNEVENTFUL APCH AND LNDG. AFTER CLRING RWY, THE GEAR PINS WERE INSTALLED AND WE WERE TOWED TO THE GATE.

Data retrieved from NASA's ASRS site as of August 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.