Allegiant Air’s flight attendants union has asked the Federal Aviation Administration to conduct a complete audit of the company’s scheduling, crew rest and fatigue procedures.

The Transport Workers Union, which represents more than 600 Allegiant flight attendants, and the Las Vegas-based airline have been at odds since the flight attendants voted in December 2010 in favor of union representation. The two sides are still negotiating, with the assistance of federal mediators, to conclude their first contract.

"We’ve had numerous reports from Allegiant flight attendants that they are being required to remain on duty for more than 14 hours, even when a replacement is available," TWU International Vice President Thom McDaniel said. "We’ve also had complaints that the company is cutting short on required rest periods."

TWU made the request Monday in a letter sent by email to FAA Administrator Michael Huerta.

"If these reports are true, then Allegiant may not be operating its flights in compliance with federal regulations," McDaniel said. "These regulations are in force because flight attendants have critical responsibilities to ensure passenger safety, comfort and convenience on every flight. If flight attendants are overworked and don’t have proper rest, it’s more difficult to deliver the high standard of service that Allegiant passengers have every right to expect."

Allegiant spokeswoman Jessica Wheeler said the company is adhering to FAA regulations.

"The safety of our operation is our top priority," she said. "We routinely work closely with FAA representatives to ensure continued compliance with all regulations, including those related to flight crew scheduling."

Allegiant, which announced several months ago it would suspend flights from seven mainland cities to Hawaii starting this week, also recently said it would eliminate 17 positions, or 45 percent, of the 37 full-time positions in Hawaii. The Hawaii-based flight attendants were told they could bid on open jobs in other cities.

Earlier this year the flight attendants won a battle with Allegiant over health care coverage when the airline reversed course and decided to make its flight attendants in Hawaii full time rather than part time.

That change enabled the flight attendants to receive health care coverage similar to Allegiant’s mainland-based attendants.