Widebody; Low Wing; 3 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Flight Crew Landed in Emergency Condition; General Maintenance Action; General Declared Emergency
Procedure; Aircraft
Level 1 HYD 1 Off occurred 35 minutes into flight at FL340. Autopilot 2 was in use. Autopilot kicked off with alert. Autopilot 1 selected with no altitude or route degradation. Hydraulic 1 quantity 2.6 gallons; QRH followed and prepared for loss of entire system once slats and flaps extended. [We] advised Maintenance of hydraulic problem; advised Local Maintenance and Operations of possible tow in. [We] advised Center that weather deviation was necessary and that we would be slowing to configure airplane passing 10;000 FT. Received Level 2 Hydraulic 1 Fail after extending slats and flaps. Hydraulic 1 quantity reduced to .2 gallons. Emergency was declared with Approach and the longest runway selected as the landing runway. Captain flew approach and landing. Crash crew inspected aircraft after right turn off of runway. No evidence of smoke or fire. [We] taxied to ramp using right turns only. Maintenance towed aircraft to gate with ground controls permission. The day prior to this flight there were the following hydraulic write-ups. Large quantity of hydraulic fluid accumulated in aft non reversible motor pump compartment; oil; found nose wheel steering return line leaking in center accessory compartment. Hydraulic System 3 over-serviced; evidence of hydraulic leak in right-hand aft wing root area. Left-hand MLG trim cylinder relief valve leaking.
A 3-engined widebody Captain experiences a Level 1 HYD 1 Off at FL340 and continues to destination. After flaps and slats are extended during approach Hydraulic System 1 fails. A normal landing ensues. The aircraft had a history of hydraulic leaks from several different locations.