The Federal Aviation Authority (FAA) has proposed fines of $5.4 million against US Airways and $3.8 million against Untied for a variety of safety procedure violations.
In US Airways' case, the FAA cited failures to perform inspections for cracking on the landing gear on Airbus A320s and engine work on a Boeing 757. These violations were found on eight planes, used to operate 1,647 total flights last fall and winter.
United's violation centers on the use of towels instead of approved caps to cover openings in the oil sump area. According to CNN, "A pilot noticed a low fuel pressure indication while on a flight from Denver, Colorado, on April 28, 2008. The pilot shut down an engine and returned to the Denver airport. United mechanics who inspected the engine found that two shop towels had been used to cover openings in the oil sump area, instead of protective caps."
Both airlines have 30 days to respond to the proposed fees.