Narrative:

During taxi to runway 1R at sfo airport, primary hydraulic pressure was lost and aircraft steering and braking were rendered inoperative. Emergency brakes were ineffective at stopping aircraft and the aircraft rolled off the hard surface into a grassy area adjacent to the taxiway. The thrust reverser on the operating engine was also deployed in an effort to stop the aircraft but was of little help. Aircraft and ground facilities were undamaged. Aircraft was towed back onto the taxiway. Cause of incident: captain failed to turn 'on' the primary hydraulic pump before aircraft was started. The safety system to warn of an engine start with the hydraulic switch in the 'off' position was inoperative. Emergency brakes were inoperative. Incident occurred due to a combination of pilot error and safety system malfunctions.

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Original NASA ASRS Text

Title: LTT PLT DOESN'T TURN ON HYD PUMP FOR TAXI OUT. ACFT TAXIES OFF THE SIDE OF THE TXWY SINCE THERE IS NO PRESSURE FOR STEERING OR BRAKING.

Narrative: DURING TAXI TO RWY 1R AT SFO ARPT, PRIMARY HYD PRESSURE WAS LOST AND ACFT STEERING AND BRAKING WERE RENDERED INOP. EMER BRAKES WERE INEFFECTIVE AT STOPPING ACFT AND THE ACFT ROLLED OFF THE HARD SURFACE INTO A GRASSY AREA ADJACENT TO THE TXWY. THE THRUST REVERSER ON THE OPERATING ENG WAS ALSO DEPLOYED IN AN EFFORT TO STOP THE ACFT BUT WAS OF LITTLE HELP. ACFT AND GND FACILITIES WERE UNDAMAGED. ACFT WAS TOWED BACK ONTO THE TXWY. CAUSE OF INCIDENT: CAPT FAILED TO TURN 'ON' THE PRIMARY HYD PUMP BEFORE ACFT WAS STARTED. THE SAFETY SYS TO WARN OF AN ENG START WITH THE HYD SWITCH IN THE 'OFF' POS WAS INOP. EMER BRAKES WERE INOP. INCIDENT OCCURRED DUE TO A COMBINATION OF PLT ERROR AND SAFETY SYS MALFUNCTIONS.

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.