Failure to follow a recommended maintenance schedule for emergency slides led Allegiant Air to ground dozens of its Boeing MD-80 family aircraft on 20 September.
Allegiant says slide manufacturer Zodiac Aerospace changed its recommendations in 2007 to call for maintenance and inspection once yearly for slides more than 15 years old.
Previously, Zodiac had recommended maintenance once every three years.
“We have been overhauling our slides on a three-year cycle,” the Las Vegas-based airline says during a media call.
Allegiant became aware of the problem following an investigation of a 16 September emergency evacuation at Las Vegas, says the airline. That flight, bound for Peoria, Illinois, was evacuated due to reports of smoke in the cabin.
“This prompted Allegiant to proactively remove aircraft from service until all slides could be brought into compliance,” the airline says in a media release.
As of Friday evening, 31 of the Allegiant’s MD-80s remained grounded.
Allegiant operates a fleet of 52 of those aircraft, although three aircraft were already out of service due to heavy maintenance work, the airline has said. Allegiant’s MD-80s have an average age of 24 years, according to the Ascend Online database.
Allegiant is sending all non-compliant slides to a third-party facility for inspection. Allegiant did not say the operator or location of the facility.
Because the slides are classified as hazardous materials, they must travel to the maintenance facility via ground transportation, a trip that takes one day each way, Allegiant says.
The maintenance and inspection process takes three days, meaning each non-compliant slide will be out of service for at least five days.
“Its an intense overhaul procedure,” says the carrier..
Allegiant says it does not know how long the process will take to complete.
Not all of Allegiant’s slides are noncompliant; many were inspected in the last year, the airline says.
It is now collecting those slides from across the fleet in an effort to get as many aircraft in the air as possible.
As of Friday afternoon, 18 of Allegiant’s MD-80s were in service, with 22 expected to by flying Saturday, says the airline.
“[We are adding] more aircraft by piecing together slides that are compliant,” says Allegiant.
Allegiant said 18 of 121 flights would not operate Friday due to the grounding. Sixteen of those flights were rescheduled until tomorrow and two were cancelled.
Allegiant has charted some aircraft from other carriers to help fill gaps in the schedule on Saturday, but expects to operate its entire schedule for the day.