The former wife of Washington real estate developer Theodore R. Hagans Jr., who died in an airplane crash a year ago, has filed a $10 million lawsuit against his estate for what she claims was the "wrongful death" of their son, who also died in the crash.

Delores Hagans claims in the suit that her former husband caused the death of their son, Theodore R. (Buster) Hagans III, 32, because he "did not have the competence to fly" the plane and was "negligent in failing to familiarize himself with emergency procedures."

Theodore (Ted) Hagans, one of the District's most successful black businessmen and a politically powerful friend of Mayor Marion Barry, died April 28, 1984, when the twin-engine plane he was piloting crashed in Timonium, Md., about 20 minutes after takeoff from Lancaster, Pa. His son was the only passenger.

Delores Hagans, who was divorced from her husband about 15 years before his death, is the representative of her son's estate, and in that capacity she is suing her daughter, Michele Hagans, 35, and two other persons who are the co-executors of the elder Hagans' estate, according to documents filed Wednesday in D.C. Superior Court.

Hagans left an estate worth close to $6 million, including apartments in the District worth almost $3 million, a $63,000 1981 Rolls Royce Silver Spur, $930,000 in corporate stocks and $14,000 cash in a safety deposit box, according to Hagans' will and other documents on file in the Register of Wills office in D.C. Superior Court.

After the payment of debts and taxes and the dividing up of joint property, Delores Hagans is to receive $50,000, the will says.

The balance of Hagans' property, minus some real estate in Florida, was to be divided between three beneficiaries, with his deceased son getting 40 percent of the remaining estate, Michele Hagans receiving 40 percent and the remaining 20 percent going to Barbara Gillum, described in the will as "my friend."

However, Hagans stated in the will that should any of those three die within 60 days of him, that person's share would be divided between the other two in the proportions "set forth."

In her suit, Delores Hagans alleges that "Mr. Hagans knew or should have known that he did not have the competence to fly a twin-engine Piper Aerostar 601-P unassisted because a Piper aircraft instructor refused to approve and provide a passing grade to Mr. Hagan upon completion of a flight training program."

The suit charges that Hagans was negligent for not having a flight instructor, safety pilot or competent pilot on board the aircraft; for failing to familiarize himself with emergency procedures and the handling characteristics of the plane; for failing to take proper action when the plane rose above a certain altitude or when it experienced a loss of fuel pressure; and for losing control of the aircraft during the descent.

Ira Furman, a spokesman for the National Transportation Safety Board, said yesterday that the probable cause of the crash is still under investigation.

At the time, witnesses reported hearing an engine "sputter" and seeing "a black cloud" pour from an engine cowling.

The suit also alleges that Hagans did not warn his son that he had failed to complete his flight training and was unfamiliar with emergency procedures.

In addition to seeking damages for the "wrongful" death of her son, Delores Hagans is also seeking damages under a "Survival Act Claim" on behalf of her son's estate, claiming that he experienced "fright, shock, and mental anguish . . . during the minutes while the aircraft plummeted to the earth."

The suit claims that, as a result of his death, Buster Hagans " . . . sustained property loss, lost wages and earning capacity" and also was "deprived of an inheritance expectancy" resulting from the death of his father.

Brian H. Siegel, the lawyer for Hagens's estate, said Delores Hagans's suit is "in litigation and we have no comment on it. We will be filing a response to the complaint within a few weeks."

Delores Hagans first filed a claim against her former husband's estate on behalf of her son's estate in November for an "undetermined sum," according to court documents.

On Jan. 4, according to court documents, Gillum petitioned the court asking that she be advised of any proposed settlement and that she be allowed to comment on it. The request was approved Feb. 11.

Gillum's petition claims that because of the death of the younger Hagans she is now entiled to one third of the remaining estate -- the original 20 percent she was provided for, plus one third of the 40 percent that would have gone to Buster Hagans if he had not died.

Gillum's petition states that she "understands" that the co-executors of the Hagans estate "are considering settling the claim . . . by a payment to Delores Hagans of perhaps as much as $1,000,000" or by transferring to her name property in Maryland with an appraised value of $986,000 that is "presently listed for sale at an asking price of $2,500,000."

Gillum stated in the document that Michele Hagan "may be presumed to have a natural affinity" for her mother, and asked to be consulted before any settlement or compromise was made.