Divorce on the installment plan might sound far-fetched, but for $8.33 per month it is now a reality to members of one General Services Administration Federal Credit Union.

Under a prepaid group insurance plan called Family Legal Services now being marketed to area banks, credit unions and financial institutions, members pay a $100 yearly fee in return for a wide range of legal services, including unlimited consultations and attorneys fees in cases involving separation and divorce, consumer law and crimes against persons, including murder.

In civil suits, medical malpractices cases or those involving injuries sustained in automobile accidents, all of which frequently involve large cash awards, the plan pays the first $1,000 with the remainder negotiable with the attorney. Tax and business law cases are not covered under the plan.

According to Nathaniel Floyd, executive vice-president of Benefit Services and is marketing the plan, members who request legal services will be referred to an attorney who is on call 24 hours a day. So far, 12 attorneys have registered for the GSA plan.

"The West Coast has been selling pre-paid legal insurance since 1967, but the concept is new on the East Coast, so many people don't understand how it works," Floyd said. Since June, District government employees have been eligible for a similar plan through their credit union. Last July, the Chrysler Corporation and the United Auto Workers announced a $17.5 million legal services plan for 150,000 present and former employees.

Floyd said that for attorneys, the pre-paid legal services, represent an alternative to advertising which was recently approved by the Supreme Court as well as something of a financial boon.

"Some lawyers feel it's a little more professional than taking out cut-rate ads in newspapers and magazines. We can direct hundreds of people in a lawyers' direction," said Floyd who added, "but we're not dealing with ambulance chasers."

Paticipating attorneys, all drawn from small and medium-size firms, are paid a monthly fee regardless of whether clients use their services. Attorneys are also required to belong to local, state and national bar associations, provide a 24-hour answering service and para-legal assistance. Corporate attorneys are excluded, according to plan administrator Walter B. Dennis, because "There's no feel for the (individual). A lot of the people using the plan are first-time users and attorneys have to be able to relate to them."

In order to prevent a deluge of calls from subscribers who want instant divorces, there is a six-month waiting period after enrollment before beginning proceedings. Consumers must wait 90 days on felony charges and cases involving wills or probates, and 30 days for consultations involving preventive law including real estate title searches.

Floyd said he thinks the plan will benefit those who have in the past been hesitant to contact lawyers, particularly regarding consumer complaints, because of fear of the cost involved.

"In the Washington area, attorney's fees for a one-hour consultation now often run about $50-60."