August 9, 1983

The Army's new Chief of Staff, Gen. John A. Wickham Jr., asserted today that poor performance of arms and equipment in his service was largely due to deficiencies in quality control in American industry. For instance, he said, all five failures in 16 flight tests of Pershing 2 missiles were caused by mistakes made by the contractor. The Martin Marietta Corporation of Bethesda, Md., is the company primarily responsible for making the medium-range missile, which is scheduled for deployment in West Germany in December. A spokesman for the missile producer, reached by telephone in Orlando, Fla., declined to comment.

A 13,000- square-foot ceiling crashed down at the PATH railroad line's Journal Square center here today, killing two people and injuring eight others. Even as emergency crews cut through the tangle of debris in a search for victims, officials of the Port Authority of New York and New Jersey announced that a ''sag'' had been found in the ceiling in April and that the ceiling collapsed while three workmen were trying to make minor repairs. The officials said there had been no reason to believe the structure was ''in imminent danger of collapse.'' The ceiling - 150 by 90 feet and estimated to weigh 50 tons - gave way at about 9 A.M., shortly after the height of the morning rush hour. Service Halted Six Hours Some 60,000 bus and rail commuters a day go through the center, 27,000 of them on the PATH line. The accident shut down all PATH service between Newark and Manhattan for more than six hours.

The White House has told the Treasury not to support a new effort in the House of Representatives to tax such employee fringe benefits as free airline tickets or use of company cars, according to a top Treasury official. Taxing such benefits may be good tax policy, he said, but it is bad pre-election year politics. ''We're going to shuffle and waffle on this one,'' the Treasury official said in commenting on the decision against a new House Ways and Means Committee bill that would, for the first time, make some fringe benefits taxable as income. ''The people who get these fringe benefits,'' he said, passing on the White House reasoning, ''are our constituents, the middle class.''

International In Guatemala, a military coup brought down the Government of Brig. Gen. Efrain Rios Montt. Brig. Gen. Oscar Humberto Mejia Victores, the Defense Minister, was sworn to succeed General Rios Montt, whose fate was not known. The new leader pledged to legalize political parties and hold elections for a constituent assembly in July that would lead eventually to presidential balloting. It was the country's second coup in 17 months. (Page A1, Column 6.) The Reagan Administration reacted with caution to the coup in Guatemala. Administration officials said it was difficult to predict how the change would affect United States- Guatemala relations or Guatemala's role in Central America. (A11:1.)

Because of an editing error, an article in Business Day on Saturday regarding withholding taxes and foreign trade incorrectly described imports from the Caribbean that can enter the United States duty free. Textiles, apparel, leather goods and watches from the area cannot enter duty free.