The airplane was substantially damaged on impacting water while attempting to land at the Atlantic City Municipal Airport/Bader Field (AIY) in Atlantic City, N.J., at about 1215 Eastern time. The Private pilot and passenger were fatally injured. Visual conditions prevailed. A witness at the departure end of Runway 11 waiting to take off stated that he heard the pilot of the accident airplane report short final, followed by an announcement that he was going around because he had a problem. The witness observed the accident airplane flip, tail under and when it was upside down, it performed a roll back to normal attitude, before entering into a left spin. The spin did not look like a normal spin; it was more like a side-to-side, flat movement, like a falling leaf. The pilot added that he observed the landing gear in the up position, both props were turning, and there was no indication of smoke or engine failures. Another witness heard the accident pilot make a normal inbound to land radio transmission. The pilot called base-to-final, and the witness observed the airplane on a left base for Runway 11. The witness then heard the accident pilot transmit, Travel Air has a problem, we are going to climb out. The airplane spun to the left, making two revolutions before hitting the water.