Narrative:

On the evening of aug/xa/97 I was finishing up a 2 day trip in sfo. We were assigned a gate at sfo on our last leg of the evening. There was a B737 parked at gate to our right and no aircraft parked at gate to our left. We entered the ramp on the south line which gave us pretty much a straight line into the gate. The mechanic was waiting for us with his lighted batons. The mechanic started giving us lead- in signals when we were approximately 250 ft short of the stop point. When we were approximately 150 ft short I noticed a food service truck parked parallel to our track on the left side of the aircraft. My initial thought and comment to the first officer was, 'boy, that food service truck looks a little close. I would not continue any further if we were not under guidance.' however, I was unable to determine if the vehicle was too close and put my trust in the mechanic's lead-in guidance. There are no lateral limit lines painted on the ramp like there are at ord. The only painted lines are angled back from the nose to define the clear zone. The initial instinct to stop was then overpwred by training over my career to trust and follow the mechanic's guide signals. I felt that he obviously must see the truck and the aircraft's wingtip. He was in better position to judge clearance than I was. His confident and positive signals lured me in. I slowed the aircraft from approximately 5 KTS to about 2-3 KTS. We were exactly on the center of the lead-in line. In fact, as we approached the gate area, I hedged a little to the right only to be corrected back to the left via the mechanic's signals. I had an urge to look off to my left, but did not since I was concentrating on the guideman. Approximately 60-80 ft short of the stop point, I felt a sharp jolt and stopped the aircraft immediately. In fact, the aircraft had stopped on its own and I set the parking brake. The mechanic then had disappeared as I knew immediately what happened. I said the few proverbial choice words to myself as anger set in. I then immediately picked up the PA and briefed the passenger what had happened. Just as I finished the briefing, the lead mechanic reappeared and was giving me signals to bring the aircraft in. I looked over to see that the food service truck had pulled forward and turned to the left. We continued to the gate uneventfully. The first officer and I went through the parking SOP's. We blocked in at XA14 local. The collision occurred at approximately XA13 local. I entered the event into the logbook. Before I completed the write-up, the lead mechanic came up to the cockpit entry. I successfully fended off the urge to vent my anger at him and asked him what happened. He appeared pretty shaken. He said that before we arrived, he had walked out and verified that the clear zone was clear. He did not see a food service truck anywhere in the area. He then went back to his lead-in position. He never saw the truck approach or park. As we neared the area and when he started giving us positive guidance, he said that his attention went to keeping the nosewheel on the lead-in line and he did not look at the wingtips from there on in. I tried to soften the situation by saying that at least no one was injured. He was definitely feeling the gravity of the situation. Supplemental information from acn 377056: I believe the mechanic was fixated on our aircraft too much and not checking our clearance. Also, the food service truck was obviously beyond the line where he should have been. This could have been prevented by better training and discipline on the truck driver's part, more alertness on the mechanic's part, and also if the captain had stopped the aircraft. It does need to be pointed out, though, that the captain expressed concern and mentioned that he would not proceed had not the mechanic been there controling us and implying that proper clearance existed by motioning for us to continue.

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Original NASA ASRS Text

Title: AN ACR B737 FLC, FOLLOWING THE DIRECTIONS OF A MARSHALLER, STRUCK A FOOD SVC TRUCK WITH THE L WING AS THEY TAXIED TOWARD THEIR GATE. THE #1 SLAT WAS DAMAGED.

Narrative: ON THE EVENING OF AUG/XA/97 I WAS FINISHING UP A 2 DAY TRIP IN SFO. WE WERE ASSIGNED A GATE AT SFO ON OUR LAST LEG OF THE EVENING. THERE WAS A B737 PARKED AT GATE TO OUR R AND NO ACFT PARKED AT GATE TO OUR L. WE ENTERED THE RAMP ON THE SOUTH LINE WHICH GAVE US PRETTY MUCH A STRAIGHT LINE INTO THE GATE. THE MECH WAS WAITING FOR US WITH HIS LIGHTED BATONS. THE MECH STARTED GIVING US LEAD- IN SIGNALS WHEN WE WERE APPROX 250 FT SHORT OF THE STOP POINT. WHEN WE WERE APPROX 150 FT SHORT I NOTICED A FOOD SVC TRUCK PARKED PARALLEL TO OUR TRACK ON THE L SIDE OF THE ACFT. MY INITIAL THOUGHT AND COMMENT TO THE FO WAS, 'BOY, THAT FOOD SVC TRUCK LOOKS A LITTLE CLOSE. I WOULD NOT CONTINUE ANY FURTHER IF WE WERE NOT UNDER GUIDANCE.' HOWEVER, I WAS UNABLE TO DETERMINE IF THE VEHICLE WAS TOO CLOSE AND PUT MY TRUST IN THE MECH'S LEAD-IN GUIDANCE. THERE ARE NO LATERAL LIMIT LINES PAINTED ON THE RAMP LIKE THERE ARE AT ORD. THE ONLY PAINTED LINES ARE ANGLED BACK FROM THE NOSE TO DEFINE THE CLR ZONE. THE INITIAL INSTINCT TO STOP WAS THEN OVERPWRED BY TRAINING OVER MY CAREER TO TRUST AND FOLLOW THE MECH'S GUIDE SIGNALS. I FELT THAT HE OBVIOUSLY MUST SEE THE TRUCK AND THE ACFT'S WINGTIP. HE WAS IN BETTER POS TO JUDGE CLRNC THAN I WAS. HIS CONFIDENT AND POSITIVE SIGNALS LURED ME IN. I SLOWED THE ACFT FROM APPROX 5 KTS TO ABOUT 2-3 KTS. WE WERE EXACTLY ON THE CTR OF THE LEAD-IN LINE. IN FACT, AS WE APCHED THE GATE AREA, I HEDGED A LITTLE TO THE R ONLY TO BE CORRECTED BACK TO THE L VIA THE MECH'S SIGNALS. I HAD AN URGE TO LOOK OFF TO MY L, BUT DID NOT SINCE I WAS CONCENTRATING ON THE GUIDEMAN. APPROX 60-80 FT SHORT OF THE STOP POINT, I FELT A SHARP JOLT AND STOPPED THE ACFT IMMEDIATELY. IN FACT, THE ACFT HAD STOPPED ON ITS OWN AND I SET THE PARKING BRAKE. THE MECH THEN HAD DISAPPEARED AS I KNEW IMMEDIATELY WHAT HAPPENED. I SAID THE FEW PROVERBIAL CHOICE WORDS TO MYSELF AS ANGER SET IN. I THEN IMMEDIATELY PICKED UP THE PA AND BRIEFED THE PAX WHAT HAD HAPPENED. JUST AS I FINISHED THE BRIEFING, THE LEAD MECH REAPPEARED AND WAS GIVING ME SIGNALS TO BRING THE ACFT IN. I LOOKED OVER TO SEE THAT THE FOOD SVC TRUCK HAD PULLED FORWARD AND TURNED TO THE L. WE CONTINUED TO THE GATE UNEVENTFULLY. THE FO AND I WENT THROUGH THE PARKING SOP'S. WE BLOCKED IN AT XA14 LCL. THE COLLISION OCCURRED AT APPROX XA13 LCL. I ENTERED THE EVENT INTO THE LOGBOOK. BEFORE I COMPLETED THE WRITE-UP, THE LEAD MECH CAME UP TO THE COCKPIT ENTRY. I SUCCESSFULLY FENDED OFF THE URGE TO VENT MY ANGER AT HIM AND ASKED HIM WHAT HAPPENED. HE APPEARED PRETTY SHAKEN. HE SAID THAT BEFORE WE ARRIVED, HE HAD WALKED OUT AND VERIFIED THAT THE CLR ZONE WAS CLR. HE DID NOT SEE A FOOD SVC TRUCK ANYWHERE IN THE AREA. HE THEN WENT BACK TO HIS LEAD-IN POS. HE NEVER SAW THE TRUCK APCH OR PARK. AS WE NEARED THE AREA AND WHEN HE STARTED GIVING US POSITIVE GUIDANCE, HE SAID THAT HIS ATTN WENT TO KEEPING THE NOSEWHEEL ON THE LEAD-IN LINE AND HE DID NOT LOOK AT THE WINGTIPS FROM THERE ON IN. I TRIED TO SOFTEN THE SIT BY SAYING THAT AT LEAST NO ONE WAS INJURED. HE WAS DEFINITELY FEELING THE GRAVITY OF THE SIT. SUPPLEMENTAL INFO FROM ACN 377056: I BELIEVE THE MECH WAS FIXATED ON OUR ACFT TOO MUCH AND NOT CHKING OUR CLRNC. ALSO, THE FOOD SVC TRUCK WAS OBVIOUSLY BEYOND THE LINE WHERE HE SHOULD HAVE BEEN. THIS COULD HAVE BEEN PREVENTED BY BETTER TRAINING AND DISCIPLINE ON THE TRUCK DRIVER'S PART, MORE ALERTNESS ON THE MECH'S PART, AND ALSO IF THE CAPT HAD STOPPED THE ACFT. IT DOES NEED TO BE POINTED OUT, THOUGH, THAT THE CAPT EXPRESSED CONCERN AND MENTIONED THAT HE WOULD NOT PROCEED HAD NOT THE MECH BEEN THERE CTLING US AND IMPLYING THAT PROPER CLRNC EXISTED BY MOTIONING FOR US TO CONTINUE.

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.