Narrative:

While being vectored for an approach at oaj the aircraft lost approximately 400-500 ft. I was entering an area of heavy rain that was part of a tropical air mass in the western part of the state. While being vectored toward the LOM by ilm departure control, I noticed the aircraft beginning to lose altitude. I began raising the nose of the aircraft to compensate. Noticing that I was not getting the response that I required, I increased the power. The combination of pitch and power was enough to stop the descent and begin regaining the lost altitude. During the encounter, ilm departure control reminded me of the 1700 ft assigned altitude. I responded by stating that I was in severe turbulence and required a vector out of the storm cell. I was given the vector that I requested and was in VMC conditions in approximately 2-3 mi. The vector placed me in an area of VMC between the LOM and the airport. This position made it possible to make a visual approach to the runway. Several factors I believe came into play are the lack of radar in the aircraft and the position of the cell over the LOM. I believe that I was told of the WX in question by ilm controllers and that its intensity was that of level 1 and/or 2. In retrospect, my desire to complete the approach should not have played a factor. The decision should have been made to hold until the approach corridor was clear. My decision to continue was based upon the information given to me by the controller. Areas of level 1 and 2 WX are routinely penetrated uneventfully. It is my opinion that I encountered a substantial windshear. I would also like to note that I have been trained by my company in the recognition and recovery from windshear encounters.

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Original NASA ASRS Text

Title: PLT FAILS TO MAINTAIN ASSIGNED ALT WHEN ENCOUNTERING DOWNDRAFT.

Narrative: WHILE BEING VECTORED FOR AN APCH AT OAJ THE ACFT LOST APPROX 400-500 FT. I WAS ENTERING AN AREA OF HVY RAIN THAT WAS PART OF A TROPICAL AIR MASS IN THE WESTERN PART OF THE STATE. WHILE BEING VECTORED TOWARD THE LOM BY ILM DEP CTL, I NOTICED THE ACFT BEGINNING TO LOSE ALT. I BEGAN RAISING THE NOSE OF THE ACFT TO COMPENSATE. NOTICING THAT I WAS NOT GETTING THE RESPONSE THAT I REQUIRED, I INCREASED THE PWR. THE COMBINATION OF PITCH AND PWR WAS ENOUGH TO STOP THE DSCNT AND BEGIN REGAINING THE LOST ALT. DURING THE ENCOUNTER, ILM DEP CTL REMINDED ME OF THE 1700 FT ASSIGNED ALT. I RESPONDED BY STATING THAT I WAS IN SEVERE TURB AND REQUIRED A VECTOR OUT OF THE STORM CELL. I WAS GIVEN THE VECTOR THAT I REQUESTED AND WAS IN VMC CONDITIONS IN APPROX 2-3 MI. THE VECTOR PLACED ME IN AN AREA OF VMC BTWN THE LOM AND THE ARPT. THIS POS MADE IT POSSIBLE TO MAKE A VISUAL APCH TO THE RWY. SEVERAL FACTORS I BELIEVE CAME INTO PLAY ARE THE LACK OF RADAR IN THE ACFT AND THE POS OF THE CELL OVER THE LOM. I BELIEVE THAT I WAS TOLD OF THE WX IN QUESTION BY ILM CTLRS AND THAT ITS INTENSITY WAS THAT OF LEVEL 1 AND/OR 2. IN RETROSPECT, MY DESIRE TO COMPLETE THE APCH SHOULD NOT HAVE PLAYED A FACTOR. THE DECISION SHOULD HAVE BEEN MADE TO HOLD UNTIL THE APCH CORRIDOR WAS CLR. MY DECISION TO CONTINUE WAS BASED UPON THE INFO GIVEN TO ME BY THE CTLR. AREAS OF LEVEL 1 AND 2 WX ARE ROUTINELY PENETRATED UNEVENTFULLY. IT IS MY OPINION THAT I ENCOUNTERED A SUBSTANTIAL WINDSHEAR. I WOULD ALSO LIKE TO NOTE THAT I HAVE BEEN TRAINED BY MY COMPANY IN THE RECOGNITION AND RECOVERY FROM WINDSHEAR ENCOUNTERS.

Data retrieved from NASA's ASRS site as of July 2007 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.