U.S. District Court Judge Aubrey E. Robinson Jr. ordered the Federal Aviation Administration yesterday to ground all DC10 jumbo jets, but then stayed his order late last night just as the FAA was preparing to implement it.

Robinson will hold a new hearing on the issue at 9 a.m. today, at which time he could reinstate the order.

Robinson's original order grounding all U.S. operated DC10s came in response to a petition from the Airline Passengers Association, which charged that inspections of DC10s ordered so far by the FAA have been "wholly inadequate." The inspections have been ordered as a result of structural failures found in the engine mounting assembly on a DC10 that crashed in Chicago May 25, killing 275 people.

Robinson's original order directed FAA Administrator Langhorne Bond to ground the 138 U.S. DC10s "until such time as the cause for the loss of the left engine on American Airlines DC10 Flight 191 is identified and sufficient corrective measures have been taken to prevent future occurrences. . ."

Robinson said in a telephone interview last night that he granted the stay "just to give the agency an opportunity to make a record." Most of the Justice Department's arguments on behalf of the FAA yesterday were based on questions of whether Robinson had jurisdiction in the matter, not whether the DC10 should still be flying. Robinson confirmed in the telephone interview that he was not impressed. "You gather correctly," he said. "I operate on what's on the record. . ."

FAA and Justice Department attorneys talked to Robinson by conference call before he granted his stay. Earlier attempts to find an appellate court judge to act failed, according to FAA officials.

While five hours of legal maneuvering were going on, the DC10s were flying. FAA officials completed their draft of the order grounding the plane and had announced that it would be issued, but then the stay came.

FAA Administrator Bond was in Europe yesterday, but his deputy, Quentin Taylor, was here and would have authority to stop domestic DC10 flights.

The FAA itself already has ordered some or all DC10s grounded on three occasions since the Chicago crash but then permitted them to fly again once inspections were completed and repairs, if necessary, were made to the engine mounting assemblies.

Windle Turley, attorney for the Airline Passengers Association (APA), a self-described consumer group that claims 50,000 members, told Robinson that the inspections the FAA had ordered so far were "wholly inadequate." He complained that the FAA in its latest grounding order issued Monday night, had failed to insist that airlines follow procedures recommended by the National Transportation Safety Board.

The safety board suggested that metal fittings that hold the engine support pylon to the wing be inspected by employing "eddy current or other approved techniques to ensure detection" of flaws. Eddy current is a sound wave test that can determine interior cracks in metal that might not be visible.

The FAA, in its order to airlines Monday night, ordered them to "visually inspect" the area in question. That order, it was later determined, applied to only five domestically operated DC10s.

Turley told a reporter after the hearing that "visual inspections in a complex structure are not just adequate; it should be the most sophisticated inspection possible."

The FAA, represented by Assistant U.S. Attorney Royce Lamberth, argued that Bond's inspection orders to date had been "adequate," but emphasized that Robinson lacked jurisdiction in the case because rulings of the FAA administer should be appealed to the U.S. Court of Appeals. Robinson rejected that argument.

When Lamberth said that "no one is required to travel on these planes; each individual who travels can make these decisions," Robinson replied:

"To 274 people, that is irreparable damage. All the airlines lose [if DC10s are gounded] is money."

The death toll in the crash was revised upward to 275 yesterday when the body of a male was found under dirt and debris in the wreckage of an old aircraft hanger that burned when the plane crashed nearby. The victim was apparently not a passenger on the plane because his body was not dismembered, Cook County Coroner Robert Stein said. That raises to three the number of persons on the ground who were killed when the plane crashed. There were no survivors on board.

The engine mounting assembly problem has captured the attention of the public as the revelation after another has come from investigators.

First, investigators on the crash site found that an important bolt was broken in the engine mounting assembly on the crashed DC10s, as was the metal flange of another engine mount. Those two points were ordered inspected and DC10s were grounded until they were.

Those inspections turned up a host of new problems in the engine mounting assembly. Cracked flages, spars and bearings were found. Another round of inspections was ordered and the planes were grounded for a second time. A total of 93 problems in the engine mounting assemblies was found on 68 planes.

In both of the first two inspections, the airlines managed to get most of their DC10 fleets back in the air in less than 24 hours.

Then on Monday afternoon the safety board suggested for the first time that a departure from recommended maintenance procedures may have been responsible for metal failures on the crashed airplane, as well as on several other airplanes.

The question was whether the engine and pylon were removed as a single unit from the aircraft - a procedure used by American Airlines as well as several other U.S. airlines - or whether they were removed and replaced separately, as was recommended by McDonnell Douglas, the DC10 manufacturer.

If they were replaced together into the wing, damage to the flange was possible because of the weight and bulk of the unit, the board said. Reinspections of airplanes in which that procedure had been used during early inspections were ordered Monday night by the FAA.

Despite all that, it has still not been determined exactly what failed first in the crashed plane. Furthermore, damage in the engine mounting assembly has been found on planes that were serviced or inspected in accordance with the approved procedures.

Additionally, many questions remain as to why the plane would not fly after the engine separated from the wing. What systems were damaged that made the plane uncontrollable? That question is receiving as much attention from the saftety board as the engine mounts.

Criticism of the DC10 came from another quarter yesterday, the Association of Flight Attendants, a 20,000-member group affiliated with the Air Line Pilots Association.

AFA President Patricia Robertson Miller called for a congressional investigation of the FAA and said the DC10, along with other wide-bodied jets, is unsafe.

She said the FAA permits the DC10, the Boeing 747 and the Lockheed £1011, all wide-bodies, to fly with one emergency exit out of operation if the number of passengers is reduced and if the exist sign is blocked off.

She also criticized an FAA waiver granted several airlines to a requirement that planes flying up to 150 miles over water must carry life rafts.

Contributing to this article were Washington Post Staff Writers Laura A. Kiernan and Keith Richburg.