The opening of the HAI Heli-Expo 1990 Convention also included a landing by the prototype McDonnell-Douglas MD530N, N530NT, in the front parking lot of the Dallas Convention center. The NOTAR ("no tail rotor") system was first flown on a Hughes OH-6A (65-12917) on Dec. 17, 1981. After modifications, a second version flew on March 12, 1986. N530NT was the third NOTAR to fly (msn 160003D, ex-N8324F) on Dec. 29, 1989 - two months before Heli-Expo 1990 - but the hot-and-high 530N version never entered production. This 530N was later broken up.