Robert Alexander/Getty Images(PHILADELPHIA) — In the next two weeks, the Federal Aviation Administration will order the inspection of at least 220 Boeing 737 engines following a deadly engine failure on a Southwest Airlines flight Tuesday.

The FAA will determine precisely which engines, and their fan blades, need to be inspected before the long-debated action will become an official order. There are more than 13,000 of these engines in service made by CFM International, jointly run by General Electric and a French company.

This directive first came about after a 2016 incident, also on Southwest, which a source tells ABC News was similar to the latest deadly incident. In both cases, metal fatigue appears to have led to a blade breaking and being ejected forward out of the engine, the National Transportation Safety Board told reporters this week.

Southwest already announced it is starting an “accelerated inspection” of its fleet after the deadly failure, and other airlines have announced their own inspection plans. American Airlines said it started additional inspections of its 737s before Tuesday’s accident, while the directive was being debated.

The two pilots of Tuesday’s Southwest Airlines Flight 1380, Captain Tammie Jo Shults and First Officer Darren Ellisor, released a statement saying their “hearts are heavy.”

“As captain and first officer of the crew of five who worked to serve our customers aboard Flight 1380 yesterday, we all feel we were simply doing our jobs. Our hearts are heavy. On behalf of the entire crew, we appreciate the outpouring of support from the public and our coworkers as we all reflect on one family’s profound loss. We joined our company today in focused work and interviews with investigators. We are not conducting media interviews and we ask that the public and the media respect our focus.”

The NTSB investigation is expected to take 12 to 15 months.

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