Southwest canceled dozens of flights to inspect engines for exploding fan blades after fatal flight (LUV)

Southwest Airlines canceled about 40 flights on Sunday to free up aircraft for enhanced engine inspections after one of its jets suffered a catastrophic failure that killed a passenger last week.

The cancellations account for roughly 1% of the 4,000 flights scheduled for Sunday, Southwest said in a statement.

According to FlightAware, the Dallas-based airline has canceled nearly 120 flight so far on Monday. It's unclear how many of those are due to inspections.

"We will continue our work to minimize flight disruptions by performing inspections overnight while aircraft are not flying, and utilizing spare aircraft, when available. We anticipate minimal delays or cancellations each day due to the inspections," Southwest said in a statement to Business Insider.

Southwest Airlines Flight 1380

One passenger, Jennifer Riordan, died as a result of the incident. Her death wasthe first in an accident aboard a US commercial airlinersince 2009.

National Transportation Safety Board investigators found evidence of cracking and metal fatigue in the area where the blade failed.

The engine in question, the CFM56-7B turbofan, is the product of a 40-year-old joint venture between GE Aviation and France's Safran Aircraft Engines called CFM International.

The CFM56 arguably the most popular jet engines in the world with more than 30,000 units produced since 1980 and is used on both civilian and military aircraft. The CFM56-7B debuted in 1997 and currently powers more than 6,700 planes in the world. CFM International is the exclusive engine supplier for the Boeing 737.

Tuesday evening, Southwest Airlines announced that its entire fleet of more than 700 CFM56-powered 737s will be inspected for cracks using ultrasonic devices within the next 30 days.

On Friday, CFM International issued a service bulletin asking for older CFM56-7B engines to undergo ultrasonic inspections. A few hours later, the Federal Aviation Administration followed up with an emergency airworthiness directive (EAD) that requires certain older CFM56-7B engines to be inspected within the next 20 days. The FAA order applies only to engines with more than 30,000 cycles which equates to roughly 20 years of service.

In a statement, Southwest clarified that the cancellations are because of the airline's own voluntary inspection program and not as a result of the FAA EAD.