MIAMI--A federal judge yesterday refused to order Eastern Airlines pilots back to work, even though Eastern warned it will otherwise be driven to bankruptcy by the four-day-old Machinists strike.

Meanwhile, a spin-off job action by pilots nationwide failed to clog airports as feared.

Eastern earlier in the day sent 2500 more non-union workers home, blaming pilots for leaving it with "no business on the books."

"If the pilots do not come back to work, Eastern Airlines is gone," company attorney David Ross said. He warned during a court hearing that Eastern was faced with bankruptcy without its 3600 pilots, who have refused to cross picket lines the Machinists union set up Saturday.

U.S. District Judge Edward B. Davis deniedEastern's request for a temporary restrainingorder less than a half hour after the three-hourhearing.

Pilots union spokesperson J.B. Stokes calledthe ruling "a victory of principle; a victory ofethics."

"We've obviously made our case. Basically whatthis means is that nothing's changed," Stokessaid, adding pilots will continue to honorMachinists picket lines.

Eastern spokesperson Robin Matell said thecompany would appeal immediately to the 11th U.S.Circuit Court of Appeals in Atlanta.

Ross said the company couldn't operate morethan 48 to 72 hours more without the pilots andcould have to file for federal bankruptcyprotection.

Matell said bankruptcy would be "a course oflast resort." He declined to speculate on how longit would be before Eastern would make such a move.

Eastern, the nation's seventh-largest airline,already has nearly shut down, saying it has beenforced to lay off a total of 9500 workers thisweek because of the pilots' adherence to theMachinists' strike in a 17-month-old contractdispute.

The airline wants $150 million in concessions;the Machinists--representing mechanics and rampservice workers--want $50 million in raises.Eastern has said it lost more than $1 billion thisdecade and $1 million a day before the strike.

"Clearly that has gotten worse," said JoeLeonard, Eastern executive vice president andchief operating officer, at a briefing announcingthe layoffs of 2500 more people yesterday.

The national pilots union had asked its 40,000members at all airlines to follow rule booksstringently starting yesterday, and there werefears of havoc of piggy-backing delays around thecountry as pilots slowly completed safetychecklists. But while the union said 60 percent ofits members followed the directive, delays werefew.

"The reports we have are that there has been noeffect on operations," said Capt. Roger Hall,spokesperson for the Air Line Pilots Association.