SAN DIEGO -- Southwest Airlines says it has canceled roughly 1 percent of its scheduled flights as it carries out inspections prompted by an engine failure that led to a passenger's death last week.
The airline has canceled 91 flights for Monday, according to flight tracker FlightAware. That is on top of nearly 50 flights canceled on Sunday. Additional cancellations are possible.
As of 8 a.m. Monday, four Southwest flights were canceled at San Diego International Airport.
The affected Southwest Boeing 737 took off Tuesday morning from New York, headed for Dallas. About 20 minutes into the flight, at about 32,500 feet, a fan blade broke off the engine and shrapnel shattered a window.
Jennifer Riordan, 43, and a mother of two, was almost sucked out of the broken window and pulled back inside by fellow passengers. She died from blunt force trauma at a hospital after the plane's emergency landing in Philadelphia.
After the incident, Southwest Airlines said it was accelerating its existing engine inspection program relating to the CFM56 engine family "out of an abundance of caution" over the following 30 days.
In a statement Sunday it said that its flight cancellations had been minimal.
"We have minimized flight disruptions this past week through actions such as proactive aircraft routings to cover open trips, performing inspections overnight, and utilizing spare aircraft, when available. On Sunday, we only canceled about 40 flights due to fan blade inspections out of a planned schedule of almost 4,000 flights," the airline said.
Southwest said its cancellations were the result of a "voluntary, accelerated engine fan blade inspection program" rather than inspections ordered by US and European aviation authorities. It recommended customers check their flights' status on its website.
The US Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA) each issued an emergency airworthiness directive on Friday requiring airlines to perform an ultrasonic inspection of certain CFM56-7B engines within 20 days.
The FAA and EASA directives came on the same day that the engine manufacturer, CFM International, issued a service bulletin recommending the CFM56-7B engine be inspected more frequently.
"CFM recommends ultrasonic inspections within the next 20 days to fan blades of CFM56-7B engines with more than 30,000 cycles since new," it said. "Also, it recommends inspections by the end of August for fan blades with 20,000 cycles, and inspections to all other fan blades when they reach 20,000 cycles."
After reaching a certain age, the engines should be inspected approximately every two years, the manufacturer said.
According to CFM International, about 680 engines will be impacted by the order to inspect engines with more than 30,000 cycles within the next 20 days. More than 150 of those have already been checked by operators, it said.
Another 2,500 engines will be impacted by the recommendation to inspect fan blades with 20,000 cycles by the end of August, CFM International said. A jet engine cycle comprises an engine start, takeoff and landing, and full shut down.
"The inspection, conducted on-wing with an ultrasonic probe along the surface of the fan blade, takes about four hours per engine," the manufacturer said.
US federal safety investigators have said the naked eye cannot detect the cracks and signs of metal fatigue that doomed the engine on Southwest Flight 1380.