The latest round in Allegiant Air's public relations battle with its pilots' union opens this week with the union's release of its third report in the last year tallying maintenance issues on aircraft that interrupted flights or departures.
The report by the Teamsters Aviation Mechanics Coalition, which is working with the Teamster local representing pilots, said the Las Vegas airline continues to suffer from a "high rate" of preventable emergency landings, flight delays, aborted takeoffs and other issues — 98 from September 2015 to January.
The coalition said 35 of those involved engine issues, including two catastrophic engine failures — a failure that causes an engine to partially break apart.
"The airline's approach to maintenance is dangerous and not up to industry standards," said Chris Moore, chair of the coalition and an aviation mechanic who wrote the report. "An emergency landing virtually every week due to maintenance issues on a fleet this size isn't normal."
Allegiant has a fleet of roughly 80 aircraft.
Allegiant officials did not respond to a request seeking comment Friday. In the past, they have accused the Teamsters of falsely portraying the airline as having safety issues as a ploy to gain leverage in stalled contract negotiations with pilots. The airline has said all commercial carriers experience the sort of issues that have been noted by the union.
The Federal Aviation Administration does not publish any comparison of airlines based on maintenance issues like emergency landings or aborted takeoffs. So it can be exceedingly difficult to empirically demonstrate one airline is safer than any other.
Of the 98 incidents in this latest report, 12 involved aircraft either flying from or to St. Pete-Clearwater International Airport, where 95 percent of the airport's passenger traffic is tied to Allegiant. A record 1.6 million passengers used the airport in 2015.
Of the dozen tied to St. Pete-Clearwater, four flights made unscheduled landings because of mechanical problems. Another five made "ground returns," which is when a flight taxiing to the runway returns to the gate. And three planes made "air returns," which means the aircraft returned to the starting airport.
The report also noted findings of the coalition's investigation of these incidents:
• Little or no documentation of mechanics' work during shift changes. A mechanic starting a shift, the coalition said, needs to know where to pick up an ongoing repair.
• Allegiant flies out of many smaller airports with little or no major commercial traffic. Allegiant often relies on contract maintenance at these airports. And many of those mechanics have little experience working on MD-80 aircraft, which make up the bulk of Allegiant's fleet.
• Allegiant maintenance teams often fail to follow proper procedure when they delay repairs to redundant aircraft components or systems under what is called an plane's "minimum equipment list," or MEL. An aircraft can fly under some circumstances with a malfunctioning component. For example, an aircraft may have two autopilot systems and still fly if one is broken. But mechanics must follow detailed rules designed to guarantee safety when something is placed on the MEL.
"Mechanics report a culture of 'just move the metal' and feel pressure to get the aircraft to the next station," the report said.
Last year, the coalition reported 65 maintenance problems that interrupted flights from September 2014 to March 2015. And 28 problems were catalogued in June and July of 2015.
Contact William R. Levesque at firstname.lastname@example.org. Follow @Times_Levesque.