Sen. Heinz, 6 Others Die in Air Crash Over School : Aviation: Light plane, helicopter collide near Philadelphia. Two children on ground are victims.

Sen. John Heinz (R-Pa.), heir to a food fortune and a leading voice in Congress on health and trade policy, was killed along with six other people Thursday when his small plane collided with a helicopter and crashed into a schoolyard.

Heinz, 52, was on his way to a meeting with constituents when his plane apparently developed landing-gear trouble near Philadelphia. A Sun Oil Co. helicopter--sent up to take a look--collided with the Heinz aircraft.

Authorities said that all three people in the plane and two in the helicopter were killed in the collision. Two children died when the flaming wreckage hit the ground outside Merion Elementary School.

Three other children and two school employees were injured.

Witnesses said that school janitor John Fowler, 48, heard the explosions then saw a 7- or 8-year-old boy run into the building, his clothing aflame. Fowler knocked the boy down and put out the fire with his hands, suffering second-degree burns.

“A teacher was trying to restrain (the boy),” Fowler said. “His pants were on fire. We knocked him down and snuffed it out.

“I saw two children on the ground,” he added. “It was too hot to get close to them.”

Anne Ravreby lives about a block from the school of 560 pupils, which her daughter attends. She noted that only parts of the first and second grades were on the playground when debris rained down.

“In another 10 minutes, they would have all been out there” for recess, she said standing amid electronic equipment, a pair of sunglasses and other aircraft debris that littered the ground for blocks in an affluent neighborhood of big houses and tall trees.

Hannah, 8, Ravreby’s daughter, said that all the children on the playground started crying when the aircraft exploded above them.

“They were just scared, they were really scared,” she said.

Joelle Morgan, 10, a fifth grader who was in math class at the time, said that “the room started shaking and the windows blew open. The teacher yelled: ‘Fire!’ Everyone was crying. Everyone wanted to go home.”

Two pilots on Heinz’s twin-engine Aerostar PA60--Rick Shreck and Tron Stegan--died in the crash. Their ages were not available. Two men in the Bell 412 helicopter were identified as Charles J. Burke, 42, and Michael Pozzano, 43. Police withheld identities of the dead children.

Federal safety investigators immediately began an investigation of the crash.

Heinz, whose grandfather and father built the H. J. Heinz empire of pickles, catsup and other foods, was considered a skilled legislator who fought to protect U.S. industry against foreign imports and played key roles on health and Social Security issues. First elected to the House in 1971 and to the Senate in 1976, he had a liberal voting record for a Republican and received strong backing from labor unions.

However, his intensity, stubbornness and aloofness tended to irritate colleagues and hampered his climb up the Senate leadership ladder.

Clifford S. Heinz of Newport Beach expressed sadness over his cousin’s death.

“We were good friends,” said Heinz, 71, a philanthropist who in 1988 gave $300,000 to UC Irvine to found the Clifford S. Heinz Chair in Economics and the Public Policy of Peace.

Heinz, a second cousin to the late senator, said the nation has “lost a valuable member of the Senate and a very valuable member of Pennsylvania politics. . . . He did a lot for that state.”

News of Heinz’s death also shocked fellow lawmakers. Sen. Timothy E. Wirth (D-Colo.), saying that he and his wife, Wren, considered Heinz and his wife, Teresa, “our dearest friends in the Senate,” paid tribute to his “intense intelligence, sparkling charm and broad vision.”

Senate Minority Leader Bob Dole (R-Kan.) called Heinz “a dynamic and dedicated public servant, a tireless champion for Pennsylvania and a good and decent family man.”

Vice President Dan Quayle, in Los Angeles for a speech, said that “we are going to miss John Heinz tremendously. He made a tremendous contribution to the U.S. Senate.”

Pennsylvania Gov. Robert P. Casey, a Democrat, is expected to appoint a Democratic replacement for Heinz within 10 days. That will allow the Democrats to boost their 56-44 Senate edge over Republicans as well as to improve their chances of retaining control of the chamber in next year’s congressional elections. State law requires that the seat be subject to an election this November.

Among those thought to be in the running for appointment are Lt. Gov. Mark Singel, who had been aiming at a challenge of Sen. Arlen Specter (R-Pa.) next year; Harris Wofford, the state’s secretary of labor and industry and a former John F. Kennedy aide close to Casey; House Democratic Whip William H. Gray III (D-Pa.), and Rep. William J. Coyne (D-Pa.).

Of that group, Coyne--who represents Pittsburgh, Heinz’s home--is the only one from western Pennsylvania. Sources said that there will be pressure on Casey to name a senator from that region. Specter is from Philadelphia.

Word of Heinz’s death came from his Washington office. At midafternoon, sobbing members of his staff began walking out of his office in the Russell Senate Office Building. A few minutes later, the senator’s legislative director, Richard Bryers, announced Heinz’s death to reporters.

As a senator, Heinz was particularly mindful of import threats to Pennsylvania’s steel industry and was one of Congress’ most vocal advocates of a retaliatory trade policy. On the Senate Finance Committee, he pushed for aggressive enforcement of anti-dumping laws and worked to deny giving administrations discretion in granting relief from economic injury caused by imports.

Heinz also was influential in efforts to solve the long-range financial problems of the Social Security system. As a strong backer of eliminating mandatory retirement, Heinz worked to end the financial penalty imposed on Social Security recipients who work after age 65. And he was the chief advocate of a successful bill to bar mandatory retirement policies by most employers.

He was a key player on legislation passed in 1987 (though repealed a year later) to cover catastrophic illness. He was also a leader in toughening rules for nursing homes that take Medicare and Medicaid patients.

“His death is a personal shock to me and a great loss to the Senate,” said California Sen. Alan Cranston, the Senate’s former No. 2 Democratic leader. “I knew him as a responsible, committed senator.”

Cranston praised Heinz for working closely with Democrats on the Banking, Housing and Urban Affairs Committee.

“John was a critical player in formulating the first major piece of housing legislation in a decade, which we enacted into law last year,” he said.

Senate Majority Leader George J. Mitchell (D-Me.) said that Heinz “gave as much care to the interests and needs of older Americans as any political leader.”

Sen. Dave Durenberger (R-Minn.) agreed, saying that Heinz “was a protector of the rights of the elderly, an advocate of a strong, affordable and fair health care system, and a tireless worker for good quality care and conditions in nursing homes.”

Tumulty reported from Merion Station and Houston reported from Washington. Staff writer Kristina Lindgren contributed to this story from Orange County.