CHICAGO, April 25 (Reuters) UAL Corp's (UAL) United Airlines said on Thursday it has reached a tentative contract deal with the union representing 23,000 ramp, customer service and other workers. The International Association of Machinists and Aerospace Workers, unit 141, said the agreement covers contracts for five different groups at the No. 2 U.S. airline. United now plans to ask all labor groups for concessions to help return the airline to financial stability. Last week United reported a $510 million loss for the first quarter. Union spokesman Joe Tiberi said the latest agreement gives the workers industry-leading contracts. The ramp workers get a 13 percent retroactive pay rise and another 7 percent upon the signing of the contract. Rank and file workers have yet to ratify the contract. The base hourly wage for ramp workers goes up to $23.49, immediately upon signing, and reaches $25.16 by the end of the deal in 2004. Upon signing the contract, the ticket and reservations agents' rate will be $24.59 per hour. Last month, United reached an agreement with 13,000 mechanics, narrowly averting a strike. The airline also held a meeting with other labor union leaders Thursday afternoon. United has said the meeting between Chief Executive Jack Creighton and union leadership was to discuss a financial recovery plan for the carrier, but would not provide details of what took place at the talks. ©2002 Reuters Limited.