TEMPORARY LOSS OF ACFT CTL IN WINDSHEAR WITH DEGRADED ACFT PERFORMANCE WHEN THE #2 PROP ON AN ATR72 RUNS AWAY IN FLAT PITCH DURING AN APCH AND MISSED APCH TO RWY 10 AT ST THOMAS; TIST; VI.

Narrative

ON FINAL TO RWY 10 AT ST THOMAS (TIST); THE #2 PROP OVERSPED AND CREATED ENORMOUS DRAG AND CTL DIFFICULTIES WITH THE ACFT. THIS OCCURRED IN MODERATE TURB AND THE TWR HAD ISSUED A LOW LEVEL WINDSHEAR ADVISORY FOR +/10 KTS ON SHORT FINAL. AFTER THE CAPT CALLED FOR THE GAR AND APPLIED FULL PWR TO THE GOOD (#1) ENG; THE AIRPLANE WAS BARELY CLBING. WE WEIGHED LESS THAN 39000 LBS IN AN AIRPLANE CERTIFIED TO LAND JUST OVER 47000 LBS. THE CTL AND PERFORMANCE DEGRADATION FROM THE PROP AT ALMOST 109% OF MAX MAY WELL HAVE LED TO AN ACCIDENT IF THE AIRPLANE HAD BEEN AT MAX LNDG WT. AFTER TURNING S OVER THE OCEAN AND CLEANING UP THE AIRPLANE; WE REFED THE CHKLIST AND THE CAPT (PER THE CHKLIST) ELECTED TO SHUT DOWN THE ENG. WITH THE WIND CONDITIONS AT TIST RPTED AT 070 DEGS AT 19 KTS GUSTING TO 26 KTS AND WINDSHEAR; WE ELECTED TO RETURN TO SAN JUAN (OUR DEP POINT). I ASKED THE CAPT IF HE WANTED TO DIVERT TO MIL STATION (ABOUT 10 MI CLOSER THAN SJU INTL) BUT HE ELECTED TO CONTINUE TO SAN JUAN. I AGREE THAT WE SHOULD NOT HAVE ATTEMPTED THE APCH AT ST THOMAS; BUT I'M NOT SURE THAT WE SHOULDN'T HAVE LANDED AT MIL STATION. THE LNDG AT TJSJ WAS UNEVENTFUL. I FEEL THAT THE COMPANY SHOULD HAVE EXPOSED US TO ENG FAILURES ON FINAL IN THE SIMULATOR INSTEAD OF CONCENTRATING SO HARD ON FAILURES AT V1. AS A CREW; WE WERE NOT WELL TRAINED ON CATASTROPHIC ENG FAILURES WHILE IN THE LNDG CONFIGN ON APCH.