Narrative:

We had a hydraulic low qty and completed the checklist by turning off the engine and auxiliary pumps on number 4 shortly after reaching cruise. Prior to TOD we revisited the checklist and determined that we should turn the pumps back on prior to gear extension. In the checklist it says to turn the pumps on before using flaps and gear. The PF turned off the autopilot and hand flew the approach. When calling for flaps 1; we got the flaps primary caution. So the flaps were slow to extend. Turning on the pumps late did not cure the problem. Read the checklist to confirm the situation and turned base for the airport. The first officer was confused with the display of the secondary flaps and was trying to control speed and altitude while monitoring a new display.communication was lacking due to 14 hour duty day and jet lag. I turned on the autopilot as PF was approaching cleared altitude. The bunkies were very involved with advocating corrective actions for the descent through cleared altitude by 400 ft. The controller confirmed we had the airport and gave us the visual. Typical [approach] that put us a little high on final with our own problem of self inflicted slow flaps. The rest of the approach and landing were uneventful. I debriefed the crew regarding use of autopilot to reduce workload; and how we interpreted the wording of the checklist was wrong and a 14 hour duty day the checklists should be pretty straight forward. On this particular checklist; I would advocate for the words to turn on the pumps before using flaps or gear. With a warning of what will happen if you start using flaps without number 4 pressurized.

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Original NASA ASRS Text

Title: A B747-400 flight crew deviated from their heading and altitude clearance while dealing with a hydraulic problem.

Narrative: We had a HYD LOW QTY and completed the checklist by turning off the ENG and AUX PUMPS on Number 4 shortly after reaching cruise. Prior to TOD we revisited the checklist and determined that we should turn the pumps back on prior to gear extension. In the checklist it says to turn the pumps on before using FLAPS AND GEAR. The PF turned off the autopilot and hand flew the approach. When calling for flaps 1; we got the FLAPS PRIMARY caution. So the flaps were slow to extend. Turning on the pumps late did not cure the problem. Read the checklist to confirm the situation and turned base for the airport. The First Officer was confused with the display of the secondary flaps and was trying to control speed and altitude while monitoring a new display.Communication was lacking due to 14 hour duty day and jet lag. I turned on the autopilot as PF was approaching cleared altitude. The bunkies were very involved with advocating corrective actions for the descent through cleared altitude by 400 FT. The Controller confirmed we had the airport and gave us the visual. Typical [approach] that put us a little high on final with our own problem of self inflicted slow flaps. The rest of the approach and landing were uneventful. I debriefed the crew regarding use of autopilot to reduce workload; and how we interpreted the wording of the checklist was wrong and a 14 hour duty day the checklists should be pretty straight forward. On this particular checklist; I would advocate for the words to turn on the pumps before using flaps or gear. With a warning of what will happen if you start using flaps without Number 4 pressurized.

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.