Fairchild Industries Inc. reported a first-quarter net loss of $11 million ($1.05 per share), resulting from the establishment of pre-tax reserves of $28 million to cover higher costs on the T46A Air Force Trainer program. The loss was narrowed by $12.3 million in tax loss benefits and investment tax credits, the company said.

The loss compared with profits of $8.6 million (40 cents) in the first quarter of 1984.

Sales declined to $205.5 million in the three months ended March 31, compared with $214.6 million in the same quarter of last year.

Fairchild, an aerospace and telecommunications company based in Chantilly, Va., said it established the reserve after reviewing the current status of the prototype airplane. The first-quarter reserve was created in addition to 1984 reserves of $11.4 million established for the project.

* Genex Corp., the Rockville biotech company, reported a first-quarter loss of $2.4 million (19 cents), 41 percent greater than a loss of $1.7 million (13 cents) in the same period of 1984.

Total revenue declined to $4.9 million in the first quarter, compared with $6 million in the same period of last year. However, product sales increased 11.7 percent to $4.2 million in the first quarter, compared with the same quarter of the year before.

The company said it forecasts a net loss for 1985, but expects the loss to be smaller than its 1984 loss of $7.4 million.

* Compucare Inc. reported a first-quarter net loss of $942,000 (17 cents), compared with profits of $369,000 (7 cents) in the same period of last year.

However, the Reston company said its revenue increased to $11.4 million from $11 million in the first quarter of 1984.

Compucare attributed the loss to factors that included corporate overhead and the cost of developing its personal computer software line.

Compucare said its results also reflect "certain expenses" related to its proposed merger with Baxter Travenol Laboratories Inc. On March 1, the companies signed an agreement for Baxter Travenol to acquire Compucare in a stock transaction worth about $73 million.