Commuter small transport lost hydraulic fluid at cruise altitude.

Attributes
ACN	161021
Time
Date	199010
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : cll
State Reference	TX
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute airway : v194
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 275 flight time total : 5700 flight time type : 2500
ASRS Report	161021
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : overcame equipment problem flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

We were at our cruise altitude of 8000' in contact with ZFW when the hydraulic fluid light came on on our annunciator. This is an indication we had lost fluid and approximately 1 gal remained. I noticed our hydraulic pressure falling also. Not wanting to lose anymore fluid, I selected the hydraulic valve to emergency, depressurizing the system. We declared an emergency, called for the emergency checklist to deal with this problem and returned to college station immediately. The D & a was completed. The emergency gear extension procedure was followed to extend the gear. We got 3 green lights, landing checklist completed and made a safe landing. We also had equipment standing by, if needed. Although I had no nose wheel steering, I managed to taxi off of the active runway and shut the aircraft down on a taxiway, assist the passenger to a van and call our maintenance people. No injuries were involved in this event. Later found a bad o-ring on the hydraulic line going into the left pressure transmitter on the left side above the left main landing gear.

Original NASA ASRS Text

Title: COMMUTER SMT LOST HYDRAULIC FLUID AT CRUISE ALT.

Narrative: WE WERE AT OUR CRUISE ALT OF 8000' IN CONTACT WITH ZFW WHEN THE HYD FLUID LIGHT CAME ON ON OUR ANNUNCIATOR. THIS IS AN INDICATION WE HAD LOST FLUID AND APPROX 1 GAL REMAINED. I NOTICED OUR HYD PRESSURE FALLING ALSO. NOT WANTING TO LOSE ANYMORE FLUID, I SELECTED THE HYD VALVE TO EMER, DEPRESSURIZING THE SYS. WE DECLARED AN EMER, CALLED FOR THE EMER CHKLIST TO DEAL WITH THIS PROB AND RETURNED TO COLLEGE STATION IMMEDIATELY. THE D & A WAS COMPLETED. THE EMER GEAR EXTENSION PROC WAS FOLLOWED TO EXTEND THE GEAR. WE GOT 3 GREEN LIGHTS, LNDG CHKLIST COMPLETED AND MADE A SAFE LNDG. WE ALSO HAD EQUIP STANDING BY, IF NEEDED. ALTHOUGH I HAD NO NOSE WHEEL STEERING, I MANAGED TO TAXI OFF OF THE ACTIVE RWY AND SHUT THE ACFT DOWN ON A TXWY, ASSIST THE PAX TO A VAN AND CALL OUR MAINT PEOPLE. NO INJURIES WERE INVOLVED IN THIS EVENT. LATER FOUND A BAD O-RING ON THE HYD LINE GOING INTO THE LEFT PRESSURE XMITTER ON THE LEFT SIDE ABOVE THE LEFT MAIN LNDG GEAR.

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.