The teen-age daughter of a woman who was killed last May while hijacking a helicopter was captured by FBI agents last night after she herself had used a phony bomb to hijack a TWA plane carrying 87 people.

Both the mother in May and the daughter yesterday attempted to use hijacking to win freedom for the same inmate of the maximum security federal penitentiary in Marion, III. The TWA jetliner had been flown at the hijacker's insistence to the Wiliamson County Airport near Marion yesterday morning.

"We have the subject and everythings is under control" FBI agents in Marion told Washington headquarters at 8:48 last night, nine hours after the plane had been seized near Kansas City. No one was injured.

The hijacker was identified by Federal Aviation Administration officials as Robin Oswald, 17. FBI agent Ed Hagerty told the Washington Post that Oswald had boarded TWA flight 541 in Louisville yesterday morning. The plane had made an intermediate stop in St. Louis en route to Kansas City. It was approaching Kansas Ccity when the hijacking occured.

Oswald's mother, Barbara Annette Oswald, was killed by a helicopter pilot May 25 after she forced him at gunpoint to fly to the Marion penitentiary. The pilot managed to seize the gun and shoot her. Mrs. Oswald was attempting to free three inmates.

Robin Oswald yesterday seeking the freedom for only one of the three, Garrett B. Trapnell. Trapnell, serving a life sentence for hijacking an airplane in 1972, was convicted yesterday in Benton, III, for conspiracy in connection with the helicopter-hijacking escape attempt.

The phony bomb device was described early in the day as three sticks of dynamite strapped to her body. The FAA was told that a stewaredess had seen something that looked like three sticks of dynamite, some wiring, and a button.

The device turned out to be three railroad flares attached to wires and a doorbell button. It would not have exploded, the FBI said.

Bud Zaret, one of the passengers and a photo firm executive from Atlantic Beach, N.Y., said the hijacker kept constantly repeating, "I want Garrett."

Only one person on the flight became hysterical, Zaret said, and she was among the first released. The hijacker permitted four people with medical problems and two infants to leave shortly after the plane landed at Marion.Later in the day, 14 more people - all of them 60 or older - were permitted to leave.

Throughout the day and into the evening, the hijacker remained in the rear of the plane, sitting first on one side of the aisle, then on the other.

After several hours the FBI was able to get a telephone into the plane.

"Once she got that phone she used it constantly," Zaret said. "She would hang up, then dial immediately." The phone was connected to an FBI command center set up on the airport.

While Oswald was talking on the phone, the remaining 67 passengers began to devise their own escape.

Zaret said that larger men on the plane would stand up and "stretch," blocking Oswald's view of the front of the plane, where the exit is. People began to leave in twos and threes. Oswald and the FBI kept talking on the phone.

There were moments of high tension.

Tommie Blake, a passenger from Columbus, Ohio, told The Washington Post that "when it got dark [Oswald] got scared, aggressive and was very demanding and threatening.

At 6 o'clock she announced that if Tranpnell were not on the plane by 6:30, 'All 72 people [left on the plane] are going to be blown from the face of the earth.'" The appointed hour passed.

Finally, the FBI's Hagerty said "she came to her senses" and "felt concerned for the other passengers." About 20 passengers were still on the plane when FBI agents boarded it. Oswald surrendered without a struggle.

Passengers were given the choice of remaining in Marion overnight or taking a special TWA flight to St. Louis or Kansas City.

The plane was alternatively hot and stuffy or cold and stuffy, passengers said.

Passengers were told individually about the hijacking by the stewardesses, Mona Wagoner and Stella Thomas, both of New York. The pilot was James D. Miller, of Phoenix, and the copilot ws Lyle D. Mitchell, of Kansas City.

The plane, a twin-jet McDonnell Douglas DC9, had no difficulty landing at the Marion airport, FAA officials said. The runaway there is longer thatn the main runaway at Washington National Airport.

After landing in Marion, the plane ran out of fuel. Then its batteries expired. An auxilary power unit - standard equipment at any major airport - had to be flown in. Although it was connected, full ventilation was never restored.

FBI and FAA officials are reluctant to discuss their tacties in such situations. But it is known that every effort is made to establish contact with a hijacker and continue talking. Psychiatrists are available at the FAA command center in Washington and frequently advise on negotiating tactis. A trained FBI negotiator was flown in from Louisville to handle the FBI's end of the telephone.

It could not be learned last night whether Oswald and Trapnell were ever permitted to talk to each other as Oswald regularly demanded.

Trapnell left the Benton courtroom three times during his trial on the helicopter case yesterday to talk with security personnel, the Associated Press reported. A reporter asked Trapnell what was happening. "I can't tell you except there's been an outside threat," he said.

When Judge Harold Baker reconvened the trial, Trapnell asked for a delay, saying "I'm in a very emotional state." The request was denied.

In an interview on CBS-TV's "60 minutes" in October 19778 Trapnell said he would break out of the Marion prison.

Two of those charged in the May plot with Trapnell entered negotiated pleas of guilty last week. Trapnell was convicted by a jury last night.

Trapnell had acted as his own attorney during the trial, and hijacker Oswald was one of his witnesses Wednesday, the Associated Press reported. The only question Trapnell asked Oswald, a St. Louis high school dropout, was whether she had ever been arrested for prositution. She denied it.