MINNEAPOLIS (AP) - The Federal Aviation Administration (FAA) is proposing an $18,000 civil penalty against United Airlines for two maintenance violations the FAA said occurred before a United jet skidded off a runway and ended up in three feet of snow in February.

The FAA disclosed the fine yesterday after The Associated Press asked about violations cited in FAA documents acquired under the Freedom of Information Act. The FAA said it notified United of the proposed penalty last Friday.

A February 25 flight with 125 people aboard slid off the runway after landing in Jackson Hole, Wyoming. No one was seriously hurt. The National Transportation Safety Board said in March that the A320 at Jackson Hole and another United A320 that also skidded off a runway had crossed wiring in their main landing gear. It is believed that caused the wheels to lock.

United checked all its A320s and found a third with the wiring problem. That aircraft was not involved in an accident.

FAA documents reviewed by the AP alleged two violations by United:

— For three weeks leading up to the Jackson Hole incident, United had operated that A320 on 66 flight legs when it "was not airworthy" according to the instructions in an Airbus manual.

— United failed to identify that wiring for anti-skid devices on the landing gear were swapped.

The FAA found that the wires were swapped when new landing gear was installed on that aircraft in Denver on February 3. The connections were tested and the plane returned to flying the next day.

A United spokeswoman said the airline did not have any immediate comment. United is a unit of Chicago-based UAL Corp.

Airline maintenance has been in the spotlight since spring, when the FAA came under fire for its handling of safety issues at Southwest Airlines Co. and AMR Corp.'s American Airlines. The agency is seeking a $7.1 million fine from American and has proposed a $10.2 million fine - its largest ever - against Southwest.