LGA TRAINEE CTLR ATTEMPTED TO DEPART TFC WITH ACFT ON A 1 PT 5 MI FINAL RESULTING IN A DIFFICULT GAR; CONFLICTING WITH A HELI OFF DEP END OF RWY 31 AT LGA.

Narrative

DCA-LGA. I WAS THE LINE CHK PLT IN R SEAT CONDUCTING IOE FOR NEW CAPT; WHO WAS THE PF; FLYING LOC RWY 31 LGA IN VMC CONDITIONS. SPACING WITH ACFT AHEAD 2.5 NM; TWR TOLD US TO CONTINUE APCH; NO LNDG CLRNC. ACFT AHEAD ON LNDG ROLLOUT; WE ARE 700 FT AGL; APPROX 2.5 NM FROM RWY 31. TWR CLRS A B737 FOR IMMEDIATE TKOF RWY 31. WE ARE DISCUSSING THE VERY LIKELY IMPENDING GAR AT 400 FT AGL; 1.5 NM FROM RWY. TWR TELLS US TO GO AROUND; TURN L HEADING 290 DEGS; MAINTAIN 2000 FT. IMMEDIATELY; SECOND VOICE ON TWR FREQ TELLS US TO TURN R 10 DEGS; MAINTAIN 2000 FT. THIS PUTS US ON APPROX 325 DEG HDG. AS WE ARE CLBING THROUGH 1300-1400 FT MSL; THE B737 RISES UP IN FRONT OF US (12-12:30 O'CLOCK POS) -- VERY CLOSE AHEAD. SIMULTANEOUSLY; THE PF TURNS SLIGHTLY L (10 DEGS) AND SHALLOWS OUR CLB ENOUGH THAT THE ACFT AHEAD OPENS R AND ABOVE US. WE ARE THEN DIRECTED TO TURN L TO 260 DEGS; CLB TO 3000 FT. RETURNED FOR UNEVENTFUL APCH AND LNDG RWY 31; LGA. I SPOKE BY PHONE WITH TWR SUPVR AFTER LNDG. HE INFORMED ME THAT TRAINING HAD BEEN IN PROGRESS; AND THAT WE WERE CONTINUED AHEAD INSTEAD OF L TURN TO 290 DEGS DUE TO POTENTIAL CONFLICT WITH HELI'S JUST W OF LGA. WE WERE; IN HIS WORDS; 'SANDWICHED IN' AND THEY DID THE ONLY THING THEY COULD. THIS WAS SINGLE RWY OPS AT LGA. IN MY OPINION; THE CONFLICT OCCURRED BECAUSE OF SATURATION IN THIS SIT: SPACING TOO TIGHT ON FINAL; ZEAL ON PART OF TWR CTLRS TO KEEP DEPS MOVING; AND INEXPERIENCE OF CTLR.