The News

 The Miami Dolphins downgraded quarterback Tua Tagovailoa to doubtful for Sunday's game against the Cleveland Browns with a hip injury.

Tagovailoa initially suffered the injury during the Dolphins' loss to the Houston Texans in Week 15, but he was able to finish the game and play in the team's win over the San Francisco 49ers in Week 16.

He downplayed the injury earlier this week, describing it as typical wear and tear at this point of the season.

"I mean, it's good. It's just like anyone else on the team and anyone else around the league," Tagovailoa said Thursday when asked how his hip felt. "You get banged up little bit towards the ending of the year, so just got to take care of that."

Tagovailoa was limited in every Dolphins practice this week and was initially listed as questionable to play Sunday.

Tagovailoa suffered a compound hip fracture during his final season at Alabama in 2019 that put his playing career in jeopardy.

He was cleared in time to play his rookie season; this would be the first instance of him missing an NFL game with a hip injury.

The next two weeks are critical for the Dolphins, who can secure a third consecutive playoff berth if they win both games, they finish with a better record than the Indianapolis Colts, and the Denver Broncos lose both of their remaining games.

If Tagovailoa cannot play Sunday, Tyler Huntley would start at quarterback for the Dolphins, with Skylar Thompson serving as the primary backup. Huntley started three games for Miami this season, resulting in a win and two losses.

In those three starts, he completed 59% of his passes for 377 yards, 1 touchdown and 1 interception.

This would be a return of sorts to Cleveland for Huntley, who signed with the Browns as a free agent in March but was released in August. Miami signed Huntley off Baltimore's practice squad in September after Tagovailoa suffered the third documented concussion of his NFL career.

 The Jeju Air plane that crashed in southwestern South Korea was a Boeing 737-800, a model that is used widely around the world.

There are about 28,000 passenger planes in service globally, according to Cirium, an aviation data provider. About 15 percent, or 4,400, are Boeing 737-800s. The plane belongs to the company’s Next-Generation 737 family of jets, the precursor to the more modern 737 Max, which was involved in two fatal accidents more than five years ago that led to a global grounding of the Max fleet.

Nearly 200 airlines use the 737-800, according to Cirium, including five in South Korea: Jeju Air, T’way Air, Jin air, Eastar Jet and Korean Air. The plane is popular in Asia, Europe and North America, and Boeing has delivered about 5,000 to customers since 1998.

“The plane in question is very safe and has a good safety record,” said Najmedin Meshkati, a professor of engineering at the University of Southern California who has studied the safety history of the Boeing 737 line.

The age of the global fleet of 737-800 planes ranges from about 5 years old to more than 27 years old. A well-maintained passenger jet can fly 20 to 30 years or even longer. According to the flight tracking website Flightradar24, the plane that crashed was 15 years old. Ryanair in Europe was the first airline to operate the aircraft, which was leased to Jeju Air in 2017 by SMBC Aviation Capital, according to Cirium.

Officials said they were investigating the cause of the crash, including the possibility that a bird strike led to a landing gear malfunction.

Boeing said in a statement on Sunday that it was in contact with Jeju Air and was ready to help the airline.

Bird strikes are not uncommon in aviation. In some cases, they have resulted in cracked windshields. Some airports deploy falcons and take other measures to keep their skies clear of birds. Muan International Airport, where the crash occurred, uses measures such as playing audio of distress calls to disperse birds as well as shooting them, according to the Korean Office of Civil Aviation.

Mr. Meshkati said that the landing gear of the 737-800 line is well designed and has a history of reliability, though poor upkeep could result in it not deploying correctly. “Maintenance is really one of the most important causes of aviation accidents,” he said.

But Mr. Meshkati and other aviation experts cautioned against rushing to judgment about such incidents. Crashes are often caused by multiple factors, which can take years to uncover through in-depth investigations.