The maker of the jet engine that blew apart on Southwest Airlines Flight 1380, marring the U.S. commercial airline industry's nine-year run without a fatality, is calling for stepped-up inspections of fan blades on older engines of that type.

The Federal Aviation Administration quickly followed suit Friday and ordered emergency ultrasonic inspections of one of the world's most popular jet engine types, the CFM56-7B made by CFM International Inc.

The FAA's action comes amid questions about whether the agency should have acted faster in light of a 2016 emergency landing caused by a midair engine failure on a Southwest flight using the same type of engine.

In the U.S., an estimated 352 engines with at least 30,000 takeoffs and landings will need to be inspected within 20 days. More than 150 engines have already been inspected by the carriers, according to CFM International.

The FAA said its directive is based on CFM's bulletin to airlines and on information gathered from the investigation into the latest Southwest accident. European regulators are expected to adopt similar requirements because there are 681 of the engines worldwide that meet the 20-day inspection criteria.

Jennifer Riordan, a 43-year old bank executive and mother of two from New Mexico, died Tuesday after she was partially sucked out of the Southwest plane when a window blew out at 32,000 feet. That led to a dramatic 20-plus minute flight for the plane's 149 passengers and crew before the plane landed safely in Philadelphia.

The death marked the first passenger fatality for the Dallas-based airline in its 47-year history.

National Transportation Safety Board investigators said the fan blade that broke off was showing signs of metal fatigue -- cracks from repeated use that are too small to be seen by the naked eye.

The engine on Flight 1380 had clocked 40,000 takeoffs and landings, Southwest CEO Gary Kelly said in a media briefing Tuesday. But he added that the engine had recorded only 10,000 since its last major overhaul.

In a prepared statement Friday night, Southwest said its maintenance program "meets or exceeds all the requirements" in the FAA's order.

CFM International also is recommending inspections by the end of August for fan blades on engines with 20,000 or more takeoff-and-landing cycles and checks to all other fan blades when they reach that mark.

CFM is a joint venture between GE Aviation and France's Safran Aircraft Engines.

The CFM56-7B engine entered commercial service in 1997 and is used in Boeing 737-600, 700, 800 and 900 jets operated by various U.S. airlines. As many as 14,000 of the CFM56-7B engines are in operation globally.

The August inspection deadline applies to at least 2,500 engines globally, according to CFM. Its bulletin said the ultrasonic inspections of fan blades take about four hours per engine.

Besides the immediate inspections, the manufacturer is also recommending similar checks every time these engines complete 3,000 takeoffs and landings.

A former federal regulator told The Associated Press that these inspections should have been called for soon after the 2016 failure involving the same engine type. CFM had issued a similar service bulletin after that emergency landing, and European regulators followed suit in March.

Jim Hall, NTSB chairman during the Clinton administration, said all CFM engines on 737s should be inspected. He also said the FAA did not move quickly enough. NTSB is yet to issue a final report on its investigation into that midair engine failure.

Last August, the FAA notified airlines that it was considering requiring inspections based on CFM's service bulletins, but it hadn't made a final decision.

"I've been concerned about the FAA from when I was chairman in terms of how quickly they move sometimes on safety matters," Hall told the AP. "That's the way the system works, and I respect that."