Pilots of a Southwest Airlines Boeing 737-700 made an emergency landing in Philadelphia on 17 April after encountering significant damage to the aircraft's left-side CFM International CFM56 turbofan.
Pictures posted on social media show a badly-mangled engine with an outward-ripped cowling and significant damage to forward area near the fan.
At least one passenger was transported to the hospital, according to media reports.
Officials have put a ground stop in place at Philadelphia due to an "emergency", according to the Federal Aviation Administration's website.
Southwest confirms the aircraft diverted to Philadelphia and says it is transferring passengers and crew to the terminal. The aircraft was carrying 143 people, it says.
"We are in the process of gathering more information," Southwest adds.
The airport and the FAA did not immediately respond to a request for information.
The aircraft was operating Southwest flight 1380 from New York LaGuardia airport to Dallas Love Field, but diverted to Philadelphia, according to FlightStats.com.
It departed LaGuardia at about 10:45 local time and ascended to about 30,000ft within 20min, then began a rapid descent, landing 15min later in Philadelphia, according to Flightradar24.com
The aircraft stopped off the runway and was met by emergency personnel and firefighters, who sprayed foam on the aircraft's left engine as passenger deplaned on the right side using stairs, live news feeds of the event show.
The 737-700, registration N772SW, is powered by CFM56-7B22 engines. Boeing delivered the 143-seat aircraft to Southwest in July 2000, according to Flight Fleets Analyzer.
The aircraft accumulated 63,000h of flight time and 36,700 cycles since February, according to the most recent data available on Flight Fleets Analyzer.