Narrative:

While at cruise FL330, master caution light flickered followed by 'ayd' annunciator light. 'A' system hydraulic pressure and quantity was observed to go to zero. QRH was accomplished (except for landing gear down). ATC was advised, emergency was declared, descent into ZZZ (nearest suitable) was started, soc was notified. Flight attendants were briefed (test). Holding was requested to allow for high terrain clearance and to allow adequate time for flight attendant passenger briefing and captain passenger briefing. Final QRH was accomplished (manual landing gear extension). Passenger were again briefed. Uneventful landing was made. Aircraft was towed to gate and passenger were deplaned. Actions of flight attendants were excellent! Support from ATC, approach, tower, emergency equipment and station personnel all excellent!

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Original NASA ASRS Text

Title: AFTER EXPERIENCING THE LOSS OF THE 'A' HYD SYS QUANTITY, A B737-300 CREW DECLARED AN EMER AND DIVERTED TO THE NEAREST SUITABLE ARPT.

Narrative: WHILE AT CRUISE FL330, MASTER CAUTION LIGHT FLICKERED FOLLOWED BY 'AYD' ANNUNCIATOR LIGHT. 'A' SYS HYD PRESSURE AND QUANTITY WAS OBSERVED TO GO TO ZERO. QRH WAS ACCOMPLISHED (EXCEPT FOR LNDG GEAR DOWN). ATC WAS ADVISED, EMER WAS DECLARED, DSCNT INTO ZZZ (NEAREST SUITABLE) WAS STARTED, SOC WAS NOTIFIED. FLT ATTENDANTS WERE BRIEFED (TEST). HOLDING WAS REQUESTED TO ALLOW FOR HIGH TERRAIN CLRNC AND TO ALLOW ADEQUATE TIME FOR FLT ATTENDANT PAX BRIEFING AND CAPT PAX BRIEFING. FINAL QRH WAS ACCOMPLISHED (MANUAL LNDG GEAR EXTENSION). PAX WERE AGAIN BRIEFED. UNEVENTFUL LNDG WAS MADE. ACFT WAS TOWED TO GATE AND PAX WERE DEPLANED. ACTIONS OF FLT ATTENDANTS WERE EXCELLENT! SUPPORT FROM ATC, APCH, TWR, EMER EQUIP AND STATION PERSONNEL ALL EXCELLENT!

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.