* About half of fleet to get evacuation slide inspections
* Cancels 18 of 121 scheduled flights Friday
* More disruptions likely Sunday and Monday
* Shares fall about 5 percent
Sept 20 (Reuters) - Allegiant Travel Co, a low-cost carrier that provides service to leisure destinations, is grounding as many as 30 of its planes, or roughly half of its fleet, to inspect emergency exit slides to comply with safety guidelines.
The company's shares fell about 5 percent on Friday, when it canceled 18 of 121 scheduled flights, a move that affected roughly 2,700 passengers.
Brian Davis, a spokesman, said 16 of the flights originally planned for Friday would operate on Saturday, when the carrier also expects to complete a full schedule of 33 flights.
Davis added that more disruptions were likely on Sunday and Monday, which are busier days. "We do anticipate more cancellations," he said during a conference call.
The Las Vegas-based discounter, which offers flights to leisure destinations such as Orlando and Fort Lauderdale in Florida and cities in Hawaii, said it had secured seven aircraft from other carriers to help it provide flights as it makes the inspections of its MD-80s.
To complete the needed checks, the slides must be taken off planes and sent to a third party for overhaul. Davis also said Allegiant was buying evacuation slides in a bid to return planes to service as soon as possible.
The FAA directed the carrier to report the status of the evacuation slides on its MD-80s while investigating an emergency evacuation of an Allegiant flight in Las Vegas on Monday. As part of the FAA review, Allegiant said it found that it was not meeting updated manufacturer guidelines that called for older slides to be overhauled every year, and so decided to pull planes from service to make the checks. Allegiant said it had been checking the MD-80 slides every three years.
"The FAA this week became aware that Allegiant Air may not have inspected some emergency evacuation slides on its MD-80 fleet at required intervals," Ian Gregor, public affairs manager with the FAA Pacific Division, said in a statement.
"We directed them to report on the slides' inspection status," Gregor added in an email.
Allegiant said it expected the slide inspections to be completed by the end of this month. The carrier added it was offering vouchers, refunds and hotel and meal accommodations to passengers whose flights were delayed or cancelled because of the slide inspections.
Las Vegas-based Allegiant operates 52 MD-80 aircraft, six Boeing Co 757-200 aircraft, and three Airbus A319 jets. The MD-80 was made by McDonnell Douglas, which Boeing acquired in 1997.
Allegiant shares closed down $5.08 at $97.91 on the Nasdaq on Friday.