Narrative:

The power back from gate at ict was a normal straight power back to all crew indications. We were moving at the pace of a slow walk, and I was monitoring the signals of the forward guideman plus thrust indications and our position on the ramp. I saw no power forward signals from the forward guideman until it was too late. I did see the left wing walker waving 1 arm forward. But did not know what he was indicating since he gave neither a stop nor a power forward signal in the second I had to evaluate his action. I received the first indication that anything was wrong when I heard a crunching sound and felt the nose rise. At that point the guideman on the nose was giving a forward signal, and I immediately came out of reverse and applied forward thrust. With the aircraft stopped and no other indications from the ramp personnel, I set the parking brake. We were then informed by ground control that the main gears were off the ramp by several ft and in the mud. Portable stairs were brought to the airplane, and our 49 passenger deplaned without incident. The plane was towed back onto the ramp under the supervision of airline's aircraft recovery team. After they inspected the aircraft and deemed it airworthy, we flew the aircraft to dfw. In order to prevent a recurrence, there needs to be better standardized procedures for the wing walkers to signal the forward guideman and the cockpit crew that power back should cease. Supplemental information from acn 233461: I also believe the ground reference used by the guideman to direct a 'come forward' should be more prominent. It was difficult for me to see the end of the yellow line he uses as a nosewheel reference, when I stood in his spot after deplaning.

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Original NASA ASRS Text

Title: ACR LGT EXPERIENCES RAMP EXCURSION DURING RAMP OP RAMP DEP PROC DURING PWRBACK OP.

Narrative: THE PWR BACK FROM GATE AT ICT WAS A NORMAL STRAIGHT PWR BACK TO ALL CREW INDICATIONS. WE WERE MOVING AT THE PACE OF A SLOW WALK, AND I WAS MONITORING THE SIGNALS OF THE FORWARD GUIDEMAN PLUS THRUST INDICATIONS AND OUR POS ON THE RAMP. I SAW NO PWR FORWARD SIGNALS FROM THE FORWARD GUIDEMAN UNTIL IT WAS TOO LATE. I DID SEE THE L WING WALKER WAVING 1 ARM FORWARD. BUT DID NOT KNOW WHAT HE WAS INDICATING SINCE HE GAVE NEITHER A STOP NOR A PWR FORWARD SIGNAL IN THE SECOND I HAD TO EVALUATE HIS ACTION. I RECEIVED THE FIRST INDICATION THAT ANYTHING WAS WRONG WHEN I HEARD A CRUNCHING SOUND AND FELT THE NOSE RISE. AT THAT POINT THE GUIDEMAN ON THE NOSE WAS GIVING A FORWARD SIGNAL, AND I IMMEDIATELY CAME OUT OF REVERSE AND APPLIED FORWARD THRUST. WITH THE ACFT STOPPED AND NO OTHER INDICATIONS FROM THE RAMP PERSONNEL, I SET THE PARKING BRAKE. WE WERE THEN INFORMED BY GND CTL THAT THE MAIN GEARS WERE OFF THE RAMP BY SEVERAL FT AND IN THE MUD. PORTABLE STAIRS WERE BROUGHT TO THE AIRPLANE, AND OUR 49 PAX DEPLANED WITHOUT INCIDENT. THE PLANE WAS TOWED BACK ONTO THE RAMP UNDER THE SUPERVISION OF AIRLINE'S ACFT RECOVERY TEAM. AFTER THEY INSPECTED THE ACFT AND DEEMED IT AIRWORTHY, WE FLEW THE ACFT TO DFW. IN ORDER TO PREVENT A RECURRENCE, THERE NEEDS TO BE BETTER STANDARDIZED PROCS FOR THE WING WALKERS TO SIGNAL THE FORWARD GUIDEMAN AND THE COCKPIT CREW THAT PWR BACK SHOULD CEASE. SUPPLEMENTAL INFO FROM ACN 233461: I ALSO BELIEVE THE GND REF USED BY THE GUIDEMAN TO DIRECT A 'COME FORWARD' SHOULD BE MORE PROMINENT. IT WAS DIFFICULT FOR ME TO SEE THE END OF THE YELLOW LINE HE USES AS A NOSEWHEEL REF, WHEN I STOOD IN HIS SPOT AFTER DEPLANING.

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.