As a result, FAA is ordering airlines use ultrasonic detection devices to inspect all 24 fan blades on older CFM56-7B engines for cracks.
Other passengers were able to pull Riordan into the plane, where passenger Peggy Phillips, a retired nurse, rushed to her aide after hearing a call for anyone who knew CPR, reports ABC-6.
The inspections recommended within the next 20 days will affect about 680 engines globally, USA regulators said. It was also first passenger fatality since 2009 for a USA commercial airline. Family, friends and community leaders are mourning the death of Riordan, a bank executive on a Southwest Airlines jet that blew an engine as she was flying home from a business trip to NY.
The FAA said it ordered the accelerated inspections in what is known as an airworthiness directive because metal fatigue in a fan blade "is likely to exist or develop in other products of the same design". About 20 minutes into the flight, at about 32,500 feet, a fan blade broke off the engine and shrapnel shattered a window.
Fellow passengers grabbed Ms Riordan, 43, and dragged her back into the plane, then tried to plug the hole after the sudden loss of cabin pressure.
Riordan was a Wells Fargo banking executive and well-known community volunteer from Albuquerque, New Mexico, the company said. The directive stipulates that these inspections must be completed within the next 20 days.
The GE-Safran partnership that built the engine said it was sending about 40 technicians to help with Southwest's inspections.
The FAA had proposed inspections last August and was going through the complicated rule-making process to get an order in place.
In August 2016, a Southwest flight made a safe emergency landing in Pensacola, Florida, after a fan blade separated from the same type of engine and debris ripped a hole above the left wing.
The Dallas-based airline agreed with that timeline, but CFM International said it should only take 12 months.