Narrative:

I was pwring back an air carrier airlines large transport at the direction of our ground crew. While making a turn to my left (tail moving left), the aircraft seemed to be moving too far back based on my knowledge of the available ramp behind us (gate X yyz). When my copilot commented that he thought we were 'getting kind of close,' I came out of reverse and applied forward thrust to stop the aircraft. Within a second or 2 we impacted an 18' concrete wall at the rear of the ramp with our right main gear. At no time did the ground marshaller change his signal for a power back, left turn. He finally gave a stop signal, after the aircraft was hung up on the wall. (I understand that the right side wing walker never signaled a stop either, but 'took cover' when the collision was apparent.) passenger were deplaned via stairs through the forward door and the only injuries were 'bumps and bruises' to the F/a's thrown to the floor. The individual directing the power back had only been doing it for a month and seemed to freeze (continued giving the same signal instead of terminating the movement) when confronted with a situation that was unfamiliar. Had we not reverted to forward thrust based on a sixth sense (?), I hate to imagine the result--the small wall was the only thing to stop us from going down a steep embankment behind us and our #4 main had broken through the wall (poor copy of picture enclosed). With reverse thrust applied, I believe we'd have had a major accident. Another case for the value of experience and training? I'm glad that my copilot was confident and relaxed enough to give me his recommendation when he felt the situation warranted it--although troubled by being involved in an incident, I'm glad our coordination prevented a serious accident. Supplemental information from acn 110638: ramp supervisors were heard to say that the ground man started our turn too late. In retrospect, I don't think our ground man was in a good enough position to determine where the entire aircraft was on the ramp.

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Original NASA ASRS Text

Title: ACFT STRUCK RETAINING WALL DURING POWER-BACK PROC.

Narrative: I WAS PWRING BACK AN ACR AIRLINES LGT AT THE DIRECTION OF OUR GND CREW. WHILE MAKING A TURN TO MY LEFT (TAIL MOVING LEFT), THE ACFT SEEMED TO BE MOVING TOO FAR BACK BASED ON MY KNOWLEDGE OF THE AVAILABLE RAMP BEHIND US (GATE X YYZ). WHEN MY COPLT COMMENTED THAT HE THOUGHT WE WERE 'GETTING KIND OF CLOSE,' I CAME OUT OF REVERSE AND APPLIED FORWARD THRUST TO STOP THE ACFT. WITHIN A SECOND OR 2 WE IMPACTED AN 18' CONCRETE WALL AT THE REAR OF THE RAMP WITH OUR RIGHT MAIN GEAR. AT NO TIME DID THE GND MARSHALLER CHANGE HIS SIGNAL FOR A PWR BACK, LEFT TURN. HE FINALLY GAVE A STOP SIGNAL, AFTER THE ACFT WAS HUNG UP ON THE WALL. (I UNDERSTAND THAT THE RIGHT SIDE WING WALKER NEVER SIGNALED A STOP EITHER, BUT 'TOOK COVER' WHEN THE COLLISION WAS APPARENT.) PAX WERE DEPLANED VIA STAIRS THROUGH THE FORWARD DOOR AND THE ONLY INJURIES WERE 'BUMPS AND BRUISES' TO THE F/A'S THROWN TO THE FLOOR. THE INDIVIDUAL DIRECTING THE PWR BACK HAD ONLY BEEN DOING IT FOR A MONTH AND SEEMED TO FREEZE (CONTINUED GIVING THE SAME SIGNAL INSTEAD OF TERMINATING THE MOVEMENT) WHEN CONFRONTED WITH A SITUATION THAT WAS UNFAMILIAR. HAD WE NOT REVERTED TO FORWARD THRUST BASED ON A SIXTH SENSE (?), I HATE TO IMAGINE THE RESULT--THE SMALL WALL WAS THE ONLY THING TO STOP US FROM GOING DOWN A STEEP EMBANKMENT BEHIND US AND OUR #4 MAIN HAD BROKEN THROUGH THE WALL (POOR COPY OF PICTURE ENCLOSED). WITH REVERSE THRUST APPLIED, I BELIEVE WE'D HAVE HAD A MAJOR ACCIDENT. ANOTHER CASE FOR THE VALUE OF EXPERIENCE AND TRNING? I'M GLAD THAT MY COPLT WAS CONFIDENT AND RELAXED ENOUGH TO GIVE ME HIS RECOMMENDATION WHEN HE FELT THE SITUATION WARRANTED IT--ALTHOUGH TROUBLED BY BEING INVOLVED IN AN INCIDENT, I'M GLAD OUR COORD PREVENTED A SERIOUS ACCIDENT. SUPPLEMENTAL INFO FROM ACN 110638: RAMP SUPVRS WERE HEARD TO SAY THAT THE GND MAN STARTED OUR TURN TOO LATE. IN RETROSPECT, I DON'T THINK OUR GND MAN WAS IN A GOOD ENOUGH POS TO DETERMINE WHERE THE ENTIRE ACFT WAS ON THE RAMP.

Data retrieved from NASA's ASRS site as of August 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.