Narrative:

Incident occurred during taxi in atl, widebody transport weighing approximately 402000 pounds on single engine taxi. While exiting ramp 1 south, executing 90 degree right turn onto parallel taxiway, lost momentum. In process of starting #1 engine, thrust from #2 was directed toward baggage vehicles at south end of ramp and rptedly blew at least 3 containers over. Thrust was normal for cross-bleed start (70 percent on #2), but the long time waiting for #1 to start and come up to idle contributed to the problem. We were stopped 45 degrees into turn and it took at least 2-3 mins to get aircraft rolling through turn. For information, single engine taxi (with APU) is an authorized procedure, at captain's discretion. However, this is the second incident I have witnessed in the past month where momentum was lost in a turn or soft spot during taxi and the breakaway thrust required caused problems. I think the company's pushing single engine taxi as a cost saving measure contributed to the problem, that perhaps a maximum weight for single engine taxi should be recommended. Supplemental information from acn 249816: short taxi, started #1 engine prior to reaching taxiway. Normal power to taxi on #1 engine is 72-75 percent N3. Starting second engine requires power from other engine to be set at 70 percent N3. The aircraft was rolling, but as we were making a right turn onto taxiway (a slight rise from ramp to taxiway), aircraft came to a stop at 45 degree angle waiting for #1 engine to come on speed. We sat for a few moments, then #1 came on speed and we proceeded to runway 9L. Timing is critical during taxi. I could have done 2 things to correct this: 1) start 2 engines at pushback or, 2) use the APU for a cross-bleed from the #1 engine so I had more power from #2 to keep the aircraft moving while making the turn. Supplemental information from acn 249583: a contributing factor to this incident was the pressure felt by flight crew to conserve fuel and taxi on reduced amount of engines, and the fact that engine start in this aircraft type takes an extended amount of time.

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Original NASA ASRS Text

Title: ACR WDB PRODUCES JET BLAST ENCOUNTER SIT FOR BAGGAGE CARTS DURING ENG START PROC.

Narrative: INCIDENT OCCURRED DURING TAXI IN ATL, WDB WEIGHING APPROX 402000 LBS ON SINGLE ENG TAXI. WHILE EXITING RAMP 1 S, EXECUTING 90 DEG R TURN ONTO PARALLEL TXWY, LOST MOMENTUM. IN PROCESS OF STARTING #1 ENG, THRUST FROM #2 WAS DIRECTED TOWARD BAGGAGE VEHICLES AT S END OF RAMP AND RPTEDLY BLEW AT LEAST 3 CONTAINERS OVER. THRUST WAS NORMAL FOR CROSS-BLEED START (70 PERCENT ON #2), BUT THE LONG TIME WAITING FOR #1 TO START AND COME UP TO IDLE CONTRIBUTED TO THE PROB. WE WERE STOPPED 45 DEGS INTO TURN AND IT TOOK AT LEAST 2-3 MINS TO GET ACFT ROLLING THROUGH TURN. FOR INFO, SINGLE ENG TAXI (WITH APU) IS AN AUTHORIZED PROC, AT CAPT'S DISCRETION. HOWEVER, THIS IS THE SECOND INCIDENT I HAVE WITNESSED IN THE PAST MONTH WHERE MOMENTUM WAS LOST IN A TURN OR SOFT SPOT DURING TAXI AND THE BREAKAWAY THRUST REQUIRED CAUSED PROBS. I THINK THE COMPANY'S PUSHING SINGLE ENG TAXI AS A COST SAVING MEASURE CONTRIBUTED TO THE PROB, THAT PERHAPS A MAX WT FOR SINGLE ENG TAXI SHOULD BE RECOMMENDED. SUPPLEMENTAL INFORMATION FROM ACN 249816: SHORT TAXI, STARTED #1 ENG PRIOR TO REACHING TXWY. NORMAL PWR TO TAXI ON #1 ENG IS 72-75 PERCENT N3. STARTING SECOND ENG REQUIRES PWR FROM OTHER ENG TO BE SET AT 70 PERCENT N3. THE ACFT WAS ROLLING, BUT AS WE WERE MAKING A R TURN ONTO TXWY (A SLIGHT RISE FROM RAMP TO TXWY), ACFT CAME TO A STOP AT 45 DEG ANGLE WAITING FOR #1 ENG TO COME ON SPD. WE SAT FOR A FEW MOMENTS, THEN #1 CAME ON SPD AND WE PROCEEDED TO RWY 9L. TIMING IS CRITICAL DURING TAXI. I COULD HAVE DONE 2 THINGS TO CORRECT THIS: 1) START 2 ENGS AT PUSHBACK OR, 2) USE THE APU FOR A CROSS-BLEED FROM THE #1 ENG SO I HAD MORE PWR FROM #2 TO KEEP THE ACFT MOVING WHILE MAKING THE TURN. SUPPLEMENTAL INFORMATION FROM ACN 249583: A CONTRIBUTING FACTOR TO THIS INCIDENT WAS THE PRESSURE FELT BY FLC TO CONSERVE FUEL AND TAXI ON REDUCED AMOUNT OF ENGS, AND THE FACT THAT ENG START IN THIS ACFT TYPE TAKES AN EXTENDED AMOUNT OF TIME.

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.