Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 12000
Aircraft Equipment Problem Critical
Flight Crew Landed in Emergency Condition; General Declared Emergency; General Maintenance Action
Aircraft
During climbout; at approximately 17;000 FT; we received an EICAS message of L HYD OVHT (Left Hydraulic Overheat). We requested to level off at 18;000 FT from Center. We accomplished the QRH procedure; which instructed us to turn off the left engine hydraulic pump. At the time; the hydraulic PSI and quantity were normal. After accomplishing the QRH; we continued our climb to cruise altitude. Some minutes after reaching cruise altitude; we received another EICAS message that the L HYD quantity was low. The message was accompanied by a thud; but I could not tell where the sound originated from. The L HYD SYS Press (Left Hydraulic System Pressure) message also appeared. At this time; one of the flight attendants also called forward to tell us they heard a strange noise. On the status page we noted 3.7rf for the left hydraulic system; and 3;100 PSI for the left PSI. The Center and right systems indicated normal. We accomplished the HYD SYS PRESS L only QRH procedure. The PTU was doing its job as we noted 3;100 system pressure on the left side. The Captain had me notify ATC that we had an abnormal condition with our hydraulics; and for the time being we intended to continue to destination. As I was doing this; he was in contact with Dispatch via ACARS notifying them of our condition. He and I began a lengthy discussion as to whether we should continue to destination; or return. We considered all factors such as weather at locations; aircraft weight; runway lengths and possible system degradations. We referenced the QRH which outlined the items powered by the PTU; Including normal flaps; landing gear etc. Although the PTU was operating and stable; we were concerned that the system might further degrade and require us to use alternate extension of gear and flaps during our approach. Our chief concern was the prospect of an overweight landing if we turned back. If it became necessary to abort the landing attempt and execute a missed approach; it would be a bad situation if we could not retract the gear and flaps during the go around. We were some 30;000 LBS or so over the maximum landing weight. Loss of an engine on approach or go around with degraded flap and gear operation could prove fatal. Given these considerations; and the fact that the weather was good at destination and had 11;000 plus FT of runway; we agreed that we wanted to continue. The Captain conveyed this to Dispatch; and they agreed also that we should continue. The Captain then coordinated a more direct routing. Each ATC facility was notified of our problem as the flight progressed southward. The Captain and I used our time reviewing and re reviewing the procedures for alternate extension of gear and flaps; should it become necessary on our approach. We also discussed our contingency plan in case the weather turned foul or we had to execute a missed approach for any reason. We reviewed the terrain surrounding the airport; and we discussed alternate airports should they become necessary. We rehearsed the scenarios and procedures over and over again; as we new we would be fatigued near the end of the flight. We would be landing near dawn after flying all night; so we wanted to make sure we had the procedures down pat so we could accomplish them with out any doubt. Once we were with destination ATC we declared an emergency; and requested emergency equipment to be standing by to monitor our landing. The Captain briefed the flight attendants for the landing. They were told to perform a 30 second review as a precaution; although we anticipated a normal landing. We once again rehearsed our procedures and then began our descent. The descent was planned a little early to give us additional time to configure the aircraft if necessary. Once we began to configure the aircraft flaps for landing; the TE flaps disagree light illuminated. At this time; the left system went to zero. We used alternate flap extension as directed by the checklist. When the gear was lowered; the gearfailed to extend. We used the alternate gear extension as directed by the checklist. The alternate systems worked as designed; and no further problems configuring the aircraft were encountered. Tower cleared us to land; and we confirmed again that the crash equipment was standing by. The Captain made a smooth touchdown. He had some difficulty deploying the right reverser. He used manual and differential breaking to bring the aircraft to a controlled stop. Steering the aircraft was difficult due to no nose wheel steering; but he was able to clear the runway using differential breaking. Once clear of the runway; we told tower that we wanted our company to tow us to the gate. The tug arrived; we shut down the engines; and were towed to the gate without further incident. The aircraft was not equipped with SATCOM; so communications with dispatch was difficult and accomplished with free text messages to Dispatch. SATCOM would have simplified this task and reduced our work load a great deal.
B757-200 First Officer reports a left hydraulic system overheat during climb out and the left engine driven pump is secured in accordance with QRH procedures. After reaching cruise an EICAS message for L Hyd Quantity and L Hyd Pressure is annunciated. The crew elects to continue to destination where alternate gear and flap extension methods are employed prior to landing. The aircraft is towed to the gate.