Narrative:

FL350, while en route to ind, the 'a' system engine driven hydraulic pump low pressure light illuminated, followed by loss of 'a' system hydraulic quantity. QRH items for loss of 'a' system hydraulic quantity were complied with. Dispatch was notified of the hydraulic system loss, and the WX was checked for ind and mdw. The opc was checked for adequate runway availability at ind and mdw. Maintenance control was consulted regarding the loss of the 'a' hydraulic system. We 3 concluded that I could safely divert to mdw. I made the decision to divert to mdw with dispatch's concurrence. ATC was notified. Flight attendant a was briefed about the loss of the hydraulic system and my decision to divert. I instructed her to brief flight attendants B and C and asked that they reassure the passenger that there was no need for alarm. I briefed the passenger and told them of my decision to divert to mdw. Special conditions and handling requirements were discussed with the first officer. Mdw operations was notified, requesting that a tug meet us at the end of taxiway 4R. We had no alternate nose wheel steering switch in this aircraft. Mdw approach vectored flight for a long final to runway 4R. The landing was uneventful. The aircraft was shut down on the runway. Maintenance pinned the gear, and the aircraft was towed to the gate. Supplemental information from acn 581038: when close, (100 NM), ATC asked for us to allow incoming aircraft to land first. We entered holding and eventually were slowed down, vectored for a 15 NM final. No special handling from ATC, no emergency declared. We did notify mdw tower, through ATC, that we would have to stop on the runway and be towed off. That took 5 mins.

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Original NASA ASRS Text

Title: DIVERSION TO ANOTHER ARPT FOR LNDG WHEN A B737-300 FLT LOSES ITS MAIN 'A' HYDRAULIC SYS S OF IND, LNDG AT MDW, IL.

Narrative: FL350, WHILE ENRTE TO IND, THE 'A' SYS ENG DRIVEN HYD PUMP LOW PRESSURE LIGHT ILLUMINATED, FOLLOWED BY LOSS OF 'A' SYS HYD QUANTITY. QRH ITEMS FOR LOSS OF 'A' SYS HYD QUANTITY WERE COMPLIED WITH. DISPATCH WAS NOTIFIED OF THE HYD SYS LOSS, AND THE WX WAS CHKED FOR IND AND MDW. THE OPC WAS CHKED FOR ADEQUATE RWY AVAILABILITY AT IND AND MDW. MAINT CTL WAS CONSULTED REGARDING THE LOSS OF THE 'A' HYD SYS. WE 3 CONCLUDED THAT I COULD SAFELY DIVERT TO MDW. I MADE THE DECISION TO DIVERT TO MDW WITH DISPATCH'S CONCURRENCE. ATC WAS NOTIFIED. FLT ATTENDANT A WAS BRIEFED ABOUT THE LOSS OF THE HYD SYS AND MY DECISION TO DIVERT. I INSTRUCTED HER TO BRIEF FLT ATTENDANTS B AND C AND ASKED THAT THEY REASSURE THE PAX THAT THERE WAS NO NEED FOR ALARM. I BRIEFED THE PAX AND TOLD THEM OF MY DECISION TO DIVERT TO MDW. SPECIAL CONDITIONS AND HANDLING REQUIREMENTS WERE DISCUSSED WITH THE FO. MDW OPS WAS NOTIFIED, REQUESTING THAT A TUG MEET US AT THE END OF TXWY 4R. WE HAD NO ALTERNATE NOSE WHEEL STEERING SWITCH IN THIS ACFT. MDW APCH VECTORED FLT FOR A LONG FINAL TO RWY 4R. THE LNDG WAS UNEVENTFUL. THE ACFT WAS SHUT DOWN ON THE RWY. MAINT PINNED THE GEAR, AND THE ACFT WAS TOWED TO THE GATE. SUPPLEMENTAL INFO FROM ACN 581038: WHEN CLOSE, (100 NM), ATC ASKED FOR US TO ALLOW INCOMING ACFT TO LAND FIRST. WE ENTERED HOLDING AND EVENTUALLY WERE SLOWED DOWN, VECTORED FOR A 15 NM FINAL. NO SPECIAL HANDLING FROM ATC, NO EMER DECLARED. WE DID NOTIFY MDW TWR, THROUGH ATC, THAT WE WOULD HAVE TO STOP ON THE RWY AND BE TOWED OFF. THAT TOOK 5 MINS.

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.