PRESIDENT REAGAN came to office determined not to appoint special advisers representing special minority groups. Every member of his administration, he promised, would be sensitive to the needs of all Americans, and no one would feel left out because of the absence of a special assistant for minorities in the White House. A good idea. The trouble is that it hasn't worked out that way. Blacks who have been appointed to posts in the administration have not been in a position to participate in policy-making on questions of direct and specific interest to blacks as a group. While they have been called upon to explain decisions that adversely affect minorities, they have not had a chance to advise the people making the decisions before the fact.

The announcement Monday that the president will now "place a key black White House staff member in the mainstream of administration policy development" is a welcome one. Melvin L. Bradley, formerly a senior consultant in the Office of Policy Development, has been named special assistant to the president and has been promised access to what is going on. The White House also announced the appointment of another accomplished black man, Wendell Wilkie Gunn, now assistant treasurer of Pepsico, to an important job handling commerce and trade issues. This brings the number of black presidential aides to six and emphasizes the fact that race is not a bar to positions that are not specifically oriented toward minority affairs.

Mr. Bradley's appointment is a good sign, and it is commendable that the White House is trying "to strengthen (its) outreach efforts among minorities and the disadvantaged." It has a lot of strengthening to do.