Narrative:

In the conga line for takeoff on runway 25R in las vegas. Aircraft ahead of us was cleared for takeoff. We were cleared into 'position and hold; be ready for immediate.' turning onto runway we were cleared for immediate takeoff. I was flying and kept aircraft rolling around corner and came up normally on the power. We were heavy. Takeoff was normal. At approximately 100-200 ft AGL was told by tower to; 'shallow your climb' due to go around on runway 19. I reduced pitch to approximately 10 degrees; climbing at approximately 500 FPM. At 300-400 ft AGL; was told to 'level off for traffic on go around runway 19.' we leveled off; saw the traffic at 3 O'clock position; same altitude; approximately 4000 ft distance; slight front to rear drift. Kept the power set at takeoff thrust and raised flaps to 1 degree and 'up;' effectively doing a level speed change at 400 ft AGL. Watched company traffic make 'left climbing' turn to pass above and behind. Told by tower to continue climb as we passed over the end of the las vegas strip. Supplemental information from acn 754494: cleared for takeoff runway 25R. At 400 ft; tower told us to level off and did not say anything else. Then they said stop climb and then told us about the traffic. The captain leveled off. Once the other aircraft was out of our area; we continued the climb. ATC did not say anything else. I told the captain afterwards that this event scared me. Had the other aircraft gone around earlier; this could have been prevented. More help from tower. It would have been safer if the other aircraft had landed. Callback conversation with reporter acn 754493 revealed the following information: the aircraft landing on runway 19L/right was on a different tower frequency and the reason for the go around was not heard nor explained. A collision most likely would not have occurred even if the tower had not given leveloff instructions.

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Original NASA ASRS Text

Title: B737 FLT CREW DEPARTING RWY 25R AT LAS RPTS CONFLICT WITH ANOTHER B737 ON GAR FROM RWY 19L/R. FLT CREW LEVELS OFF AT TWR'S INSTRUCTION TO ALLOW GAR TO PASS ABOVE AND BEHIND.

Narrative: IN THE CONGA LINE FOR TKOF ON RWY 25R IN LAS VEGAS. ACFT AHEAD OF US WAS CLRED FOR TKOF. WE WERE CLRED INTO 'POS AND HOLD; BE READY FOR IMMEDIATE.' TURNING ONTO RWY WE WERE CLRED FOR IMMEDIATE TKOF. I WAS FLYING AND KEPT ACFT ROLLING AROUND CORNER AND CAME UP NORMALLY ON THE PWR. WE WERE HVY. TKOF WAS NORMAL. AT APPROX 100-200 FT AGL WAS TOLD BY TWR TO; 'SHALLOW YOUR CLB' DUE TO GAR ON RWY 19. I REDUCED PITCH TO APPROX 10 DEGS; CLBING AT APPROX 500 FPM. AT 300-400 FT AGL; WAS TOLD TO 'LEVEL OFF FOR TFC ON GAR RWY 19.' WE LEVELED OFF; SAW THE TFC AT 3 O'CLOCK POS; SAME ALT; APPROX 4000 FT DISTANCE; SLIGHT FRONT TO REAR DRIFT. KEPT THE PWR SET AT TKOF THRUST AND RAISED FLAPS TO 1 DEG AND 'UP;' EFFECTIVELY DOING A LEVEL SPD CHANGE AT 400 FT AGL. WATCHED COMPANY TFC MAKE 'L CLBING' TURN TO PASS ABOVE AND BEHIND. TOLD BY TWR TO CONTINUE CLB AS WE PASSED OVER THE END OF THE LAS VEGAS STRIP. SUPPLEMENTAL INFO FROM ACN 754494: CLRED FOR TKOF RWY 25R. AT 400 FT; TWR TOLD US TO LEVEL OFF AND DID NOT SAY ANYTHING ELSE. THEN THEY SAID STOP CLB AND THEN TOLD US ABOUT THE TFC. THE CAPT LEVELED OFF. ONCE THE OTHER ACFT WAS OUT OF OUR AREA; WE CONTINUED THE CLB. ATC DID NOT SAY ANYTHING ELSE. I TOLD THE CAPT AFTERWARDS THAT THIS EVENT SCARED ME. HAD THE OTHER ACFT GONE AROUND EARLIER; THIS COULD HAVE BEEN PREVENTED. MORE HELP FROM TWR. IT WOULD HAVE BEEN SAFER IF THE OTHER ACFT HAD LANDED. CALLBACK CONVERSATION WITH RPTR ACN 754493 REVEALED THE FOLLOWING INFO: THE ACFT LNDG ON RWY 19L/R WAS ON A DIFFERENT TWR FREQ AND THE REASON FOR THE GAR WAS NOT HEARD NOR EXPLAINED. A COLLISION MOST LIKELY WOULD NOT HAVE OCCURRED EVEN IF THE TWR HAD NOT GIVEN LEVELOFF INSTRUCTIONS.

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.