THE FLC OF THE CORP JET ON ILS APCH TO HPN RESPONDED AS PER PROC TO A WINDSHEAR ALERT WITH A GAR. THE CTLR ASSIGNED 2000 FT INSTEAD OF THE PUBLISHED 3000 FT. THE CAPT (PF) EXCEEDED 2000 FT BY 300 FT. THE PF GOT RIGHT BACK TO 2000 FT AND THE CTLR NEVER SAID ANYTHING.

Narrative

ON APCH TO RWY 34 DURING HIGH WIND CONDITIONS (FORECAST TO BE NW 15-25 KTS AT ETA; ACTUAL 20-40 KTS; WITH GUSTS RPTED OVER 50 KTS THROUGH NEW YORK METRO AREA) SEVERE TURB ON SHORT FINAL; COUPLED WITH AN AIRSPD LOSS OF 30+ KTS AND CONSEQUENT WINDSHEAR ALERT AURAL WARNING PROMPTED AN IMMEDIATE GAR USING WINDSHEAR ESCAPE PROC. THE TWR ISSUED A MISSED APCH HDG AND ALT ASSIGNMENT WHILE; AS PLT I WAS NATURALLY AND INTENTLY FOCUSED ON SAFELY FLYING THE ACFT TO A SAFE ALT. SINCE THE JET SEEMED TO HESITATE AS GAR THRUST WAS APPLIED; MY CONCENTRATION LEVEL WAS TOTALLY ABSORBED INTO ASSURING SAFETY OF FLT DURING THIS MANEUVER AND THOUGHT THE CTLR ISSUED ALT ASSIGNMENT THE USUAL 3000 FT WHEN IN FACT WAS 2000 FT; AS MY COPLT POINTED OUT AS I CLBED THROUGH THE ASSIGNED ALT BY 300 FT. I PROMPTLY DSNDED BACK DOWN TO 2000 FT; AND WAS SUBSEQUENTLY SWITCHED OVER TO DEP CTL; WHO COINCIDENTALLY IMMEDIATELY CLBED US TO 3000 FT. THE TWR NEVER RESPONDED TO OUR ALT BUST; WHICH WAS QUITE UNINTENTIONAL. COMMENTS: I BELIEVE I HEARD A DIFFERENT ALT BEING ASSIGNED DUE TO THE FOLLOWING REASONS: 1) THE CTLR ISSUED THE CLRNC AT A VERY CRITICAL TIME WHEN MY CONCENTRATION LEVEL WAS TOTALLY FOCUSED ON FLYING THE ACFT OUT OF A POTENTIALLY DISASTROUS SIT. 2) I THUS PERCEIVED AN ALT ASSIGNMENT WHICH WAS ROUTINELY ISSUED AT THIS ARPT; OUR HOME BASE. AS A FOOTNOTE TO THIS DESCRIPTION; THE LOW LEVEL TURB WAS SO SEVERE AT SOME POINTS THAT ALT EXCURSIONS OF 200-300 FT WERE NOT UNUSUAL THIS DAY IN THE AREA; AS WE EXPERIENCED PARTICULARLY IN THE AREA OF JFK ARPT; WHERE; GIVEN THE INCREASING WINDS AND TURB IN THE AREA; WE DECIDED WAS THE SAFEST PLACE TO LAND UNDER THE PREVAILING CIRCUMSTANCES.