Narrative:

About 30 ft into the pushback from gate; we felt the tow bar snap. The tug operator confirmed that on the intercom. The ground crew quickly had another one hooked up and we recommenced the pushback. #2 had been started during the first attempt; and #1 was started during the second. After about another 10 ft; the second bar snapped. Ground crew confirmed this and reported the second bar clear and no aircraft damage. I asked the ramper to stay on the line while we sorted things out on our end. During the after start flow; we discovered that all 4 hydraulic pumps were on. We had sufficient clearance to turn out since the adjacent gate was unoccupied. After asking the ground crew to wing-walk through the turn; I cleared them off and taxied out after receiving their thumbs-up clearance. We were late getting the before start checklist done because we were attempting to determine what the RVR was. I had already gotten a revision to my release for a takeoff alternate. We had been scheduled for over 1 hour on the ground and then got in 35 mins early from mci. With all that ground time; we requested ground power; which took a couple of attempts to get hooked up. In that disruption of the normal routine during parking; the entire parking checklist was probably not accomplished and the hydraulic pumps had been on the entire time. In retrospect; I realize that we were in a situation of neither gate services nor straight APU power; and getting it sorted out disrupted/distraction us enough to not complete that checklist. Same thing happened on the pushback evolution with the WX distraction.

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Original NASA ASRS Text

Title: A B737-700 CREW FAILED TO COMPLETE BOTH THE SHUTDOWN AND BEFORE START CHKLISTS; LEAVING THE HYD PUMPS ON; AND SUBSEQUENTLY BROKE 2 TOW BARS.

Narrative: ABOUT 30 FT INTO THE PUSHBACK FROM GATE; WE FELT THE TOW BAR SNAP. THE TUG OPERATOR CONFIRMED THAT ON THE INTERCOM. THE GND CREW QUICKLY HAD ANOTHER ONE HOOKED UP AND WE RECOMMENCED THE PUSHBACK. #2 HAD BEEN STARTED DURING THE FIRST ATTEMPT; AND #1 WAS STARTED DURING THE SECOND. AFTER ABOUT ANOTHER 10 FT; THE SECOND BAR SNAPPED. GND CREW CONFIRMED THIS AND RPTED THE SECOND BAR CLR AND NO ACFT DAMAGE. I ASKED THE RAMPER TO STAY ON THE LINE WHILE WE SORTED THINGS OUT ON OUR END. DURING THE AFTER START FLOW; WE DISCOVERED THAT ALL 4 HYD PUMPS WERE ON. WE HAD SUFFICIENT CLRNC TO TURN OUT SINCE THE ADJACENT GATE WAS UNOCCUPIED. AFTER ASKING THE GND CREW TO WING-WALK THROUGH THE TURN; I CLRED THEM OFF AND TAXIED OUT AFTER RECEIVING THEIR THUMBS-UP CLRNC. WE WERE LATE GETTING THE BEFORE START CHKLIST DONE BECAUSE WE WERE ATTEMPTING TO DETERMINE WHAT THE RVR WAS. I HAD ALREADY GOTTEN A REVISION TO MY RELEASE FOR A TKOF ALTERNATE. WE HAD BEEN SCHEDULED FOR OVER 1 HR ON THE GND AND THEN GOT IN 35 MINS EARLY FROM MCI. WITH ALL THAT GND TIME; WE REQUESTED GND PWR; WHICH TOOK A COUPLE OF ATTEMPTS TO GET HOOKED UP. IN THAT DISRUPTION OF THE NORMAL ROUTINE DURING PARKING; THE ENTIRE PARKING CHKLIST WAS PROBABLY NOT ACCOMPLISHED AND THE HYD PUMPS HAD BEEN ON THE ENTIRE TIME. IN RETROSPECT; I REALIZE THAT WE WERE IN A SITUATION OF NEITHER GATE SVCS NOR STRAIGHT APU PWR; AND GETTING IT SORTED OUT DISRUPTED/DISTR US ENOUGH TO NOT COMPLETE THAT CHKLIST. SAME THING HAPPENED ON THE PUSHBACK EVOLUTION WITH THE WX DISTR.

Data retrieved from NASA's ASRS site as of January 2009 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.