Narrative:

During initial climb; hydraulic ovht system 4 EICAS displayed. Accomplished hydraulic ovht system 4 QRH. Per procedure; when hydraulic ovht system 4 messaged blanked; selected demand pump to automatic. After several minutes; hydraulic ovht system 4 EICAS displayed again. Contacted dispatch via satcom with patch to maintenance control. Discussed additional trouble shooting options with tomc and elected not to conduct further trouble shooting procedures as aircraft was in a stabilized configuration. Discussed aircraft status with maintenance control and dispatch regarding operational impact of inoperative systems. My primary concern was the need for alternate gear extension at destination which would preclude gear retraction in the event of a go around or missed approach. Destination weather forecast for our arrival required naming an alternate. Planned fuel at destination would be insufficient for a gear extended diversion to this alternate. Based on lack of adequate fuel for a diversion from planned destination to the named alternate; I made the decision not to continue to destination. In coordination with maintenance control and dispatch; I determined a return to be the safest course of action. I requested and received revised ATC clearance for return. Notified ATC of a planned fuel jettison and conducted fuel jettison procedure per QRH. Jettisoned approximately 198.0 pounds fuel and reduced aircraft to below maximum structural landing weight. At the suggestion of maintenance control and based on my systems knowledge; I exercised my captain's emergency authority to modify the QRH procedure for alternate gear extension and initial flap selection. During the initial hydraulic ovht system 4 procedure; it took approximately fifteen minutes for the system to overheat after returning the demand pump to automatic per the procedure. To avoid the mechanical stress of a free fall extension of the wing gear and to reduce cockpit workload by simplifying the flap extension procedure; I selected demand pump 4 to automatic for approximately one minute while extending the gear normally and selecting flaps 5. Once the gear and flaps were in this position; I turned off demand pump 4. During this time I monitored the hydraulic system page and noted system 4 hydraulic temperature remained in the normal range with no EICAS displayed. Final flap selection was conducted in secondary mode and aircraft was configured per hydraulic ovht system 4 QRH procedure. Dispatch provided landing data for landing on longest available runway. Normal landing below maximum landing weight.

Related reports:

Google
 

Original NASA ASRS Text

Title: B747 Captain reports a HYD OVHT SYS 4 EICAS message during climb. QRH procedures are applied; the overheat returns and the decision is made to return to the departure airport.

Narrative: During initial climb; HYD OVHT SYS 4 EICAS displayed. Accomplished HYD OVHT SYS 4 QRH. Per procedure; when HYD OVHT SYS 4 messaged blanked; selected Demand Pump to AUTO. After several minutes; HYD OVHT SYS 4 EICAS displayed again. Contacted Dispatch via SATCOM with patch to Maintenance Control. Discussed additional trouble shooting options with TOMC and elected not to conduct further trouble shooting procedures as aircraft was in a stabilized configuration. Discussed aircraft status with Maintenance Control and Dispatch regarding operational impact of inoperative systems. My primary concern was the need for alternate gear extension at destination which would preclude gear retraction in the event of a go around or missed approach. Destination weather forecast for our arrival required naming an alternate. Planned fuel at destination would be insufficient for a gear extended diversion to this alternate. Based on lack of adequate fuel for a diversion from planned destination to the named alternate; I made the decision not to continue to destination. In coordination with Maintenance Control and Dispatch; I determined a return to be the safest course of action. I requested and received revised ATC clearance for return. Notified ATC of a planned fuel jettison and conducted Fuel Jettison procedure per QRH. Jettisoned approximately 198.0 pounds fuel and reduced aircraft to below maximum structural landing weight. At the suggestion of Maintenance Control and based on my systems knowledge; I exercised my Captain's Emergency Authority to modify the QRH procedure for alternate gear extension and initial flap selection. During the initial HYD OVHT SYS 4 procedure; it took approximately fifteen minutes for the system to overheat after returning the Demand Pump to AUTO per the procedure. To avoid the mechanical stress of a free fall extension of the wing gear and to reduce cockpit workload by simplifying the flap extension procedure; I selected Demand Pump 4 to AUTO for approximately one minute while extending the gear normally and selecting flaps 5. Once the gear and flaps were in this position; I turned off Demand Pump 4. During this time I monitored the HYD SYS page and noted System 4 hydraulic temperature remained in the normal range with no EICAS displayed. Final flap selection was conducted in secondary mode and aircraft was configured per HYD OVHT SYS 4 QRH procedure. Dispatch provided landing data for landing on longest available runway. Normal landing below maximum landing weight.

Data retrieved from NASA's ASRS site as of July 2013 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.