Aviation Distributors Inc.:

The Irvine redistributor of aircraft parts and provider of inventory management services posted second quarter net income of $608,000, or 20 cents a share, down 21% from the $768,000, or 43 cents a share, recorded for the same period of 1996. The company attributed the earnings decline to higher expenses related to increased revenue and the impact of a tax credit in the year-earlier period. Sales increased 45% to $10.3 million from $7.1 million.

First-half profit more than doubled to $915,000, or 35 cents a share, from $397,000, or 22 cents a share, for the first half of 1996. Sales were up 69% to $19.8 million from $11.7 million.