By DAVE CARPENTER (AP) Tom Reardon, assistant general chairman of the International Association of Machinist and Aerospace... CHICAGO (AP) - United Airlines mechanics and aircraft cleaners approved a contract Tuesday that will give them their first raise since 1994 and end a bitter two-year dispute. The contract was ratified by 59 percent of the voting membership, union officials said. The approval averted a strike that could have started as soon as 12:01 a.m. Thursday EST. Analysts have said a walkout would have grounded the airline and forced it into bankruptcy. "Today's ratification puts a long and difficult process behind us," said United's chief executive officer, Jack Creighton. The ratification removes a key obstacle for the struggling carrier as it pursues a recovery plan aimed at stemming its financial hemorrhaging. The Elk Grove Village, Ill.-based airline lost an industry-record $2.1 billion last year and its troubles have continued - the carrier said Tuesday that passenger traffic in February fell 13.8 percent from a year ago. The 12,800 mechanics and cleaners resoundingly rejected a previous contract offer three weeks ago and authorized a strike. But United sweetened the terms of the five-year pact and negotiators reached a tentative agreement Feb. 18. "I want to thank our members at United for the strong support they gave their negotiating committee under very difficult circumstances," said union president Scotty Ford. "Their determination and professionalism allowed the negotiating committee to obtain the best agreement possible." Under the new contract, senior mechanics' pay would go from $25.60 an hour to $35.14, or about $73,000 a year. For top-scale aircraft cleaners, hourly pay would increase 19 percent to $19.76 an hour, or about $41,000 a year. Those figures were unchanged from the previous offer, crafted by a presidential emergency board. But United made other key changes in order to win the approval of negotiators from District 141-M of the International Association of Machinists and Aerospace Workers. The airline increased the retroactive pay due each mechanic to $16,500 from $12,500, speeded up the timetable under which it will be paid, boosted pensions and agreed workers would retain the right to vote on concessions envisioned as part of United's emergency recovery plan. Some mechanics remained opposed because they disagreed with the amount or timing of retroactive wages for work since the contract came up for renewal in July 2000. Retroactive pay won't begin until December. Moving to ensure approval, United went to court last week to remove another sore spot with mechanics - an injunction it obtained last year in an effort to end work slowdowns