AN A319 CREW EXECUTED A GAR IN TURB WITH +/-40 KT WINDS BECAUSE GND SPD MINIMUMS DID NOT SLOW THE ACFT ENOUGH TO FOLLOW SLOWER TFC AND ALSO CREATED A POTENTIAL FLAP OVERSPD CONDITION.

Narrative

ON ILS RWY 22 LGA; SEVERAL SMALL ACFT HAD RPTED ONLY +/-10 KTS ON FINAL APCH AT APPROX 400 FT. WE WERE CLRED FOR THE APCH; ILS RWY 22. FLT CONDITIONS LIGHT TO MODERATE CHOP AND LIGHT TO MODERATE RAIN ONLY. MODERATE RAIN ON RADAR DISPLAYED MORE THAN 3 MI W OF LGA. BY 1000 FT AGL; RAIN WAS STARTING TO DISPLAY WITHIN 2 MI OF LGA AND INCREASING IN INTENSITY. BY 600 FT; RAIN DISPLAY SHOWED RED AND MAGENTA NEAR ARPT. TURB WAS NOW APCHING MODERATE AND AIRSPD SHOWED +/- 15 KT DEV. GAR WAS COMMENCED AT APPROX 600 FT AGL. DURING GAR; AIRSPD FLUCTUATION EXCEEDED +/-35 KTS. PIREP WAS ISSUED. ATC COMMANDED LEVELOFF AT 1000 FT MSL. OUR FLT REPLIED UNABLE DUE TO MODERATE TO SEVERE TURB AND AIRSPD FLUCTUATIONS GREATER THAN +/-40 KTS. ACFT RETURNED TO LGA WHEN WX GOT BETTER; FOR AN UNEVENTFUL LNDG. SEVERAL MAINT PROBS THAT OCCURRED ON WAY TO LGA AND LATE ARR AT PIT FOR PIT-LGA LEG CONTRIBUTED TO HIGH WORKLOAD AND EVENT. ACFT OUT OF HVY MAINT WITHOUT TEST HOP CONTRIBUTED TO PROBS. NO FO RAIN REPELLANT CONTRIBUTING FACTOR. AIRBUS GND SPD MINIMUM FORCED ACFT TO HOLD INDICATED AIRSPD TOO HIGH TO FIT IN WITH EXISTING TFC. BOTH OUR AIRBUS AND ANOTHER COMPANY AIRBUS WERE FORCED INTO A GAR SITUATION BECAUSE GND SPD MINIMUMS KEPT ACFT TOO FAST TO FOLLOW DASH 8 ACFT AND REGIONAL JET ACFT IN SEQUENCE. GND SPD MINIMUM WAS ALSO UNUSABLE BECAUSE OF POTENTIAL FLAP OVERSPD PROBS. ACFT WAS UNABLE TO COPE WITH ANY OF THE APCH OR MISSED APCH SPDS IN AUTOFLT; REQUIRING HAND FLOWN MANUAL THROTTLE; LLWS GAR. THIS AUTOFLT SYS IS A HORRIBLE DESIGN FOR LOW LEVEL GARS AND APCHS IN WINDY WX.