The Miracle on the Hudson will take over movie screens this weekend with the release of "Sully," a new Clint Eastwood film about the life of Chesley Sullenberger, the pilot who pulled off an emergency plane landing on the Hudson River on Jan. 15, 2009.

Tom Hanks stars as "Sully," who struggles with post-traumatic stress disorder and public backlash after his split-second decision to save U.S. Airways Flight 1549. The movie already has an impressive 81 percent on Rotten Tomatoes, but viewers may wonder about the veracity of the film. Just how true is this dramatic retelling?

Here are the basic facts: Flight 1549 was en route from New York City to Charlotte, North Carolina, with 155 people on board when it hit a flock of Canada geese, according to National Geographic. The engines failed, and Sullenberger — worried the Airbus A320 wouldn't make it back to the airport — decided to land on the water. He did, and everyone survived.

But afterward, the National Transportation Safety Board launched a 15-month investigation into the incident and Sullenberger himself, who took a cell phone call in the cockpit before liftoff. The probe found that, in simulations, pilots were able to land at the airport rather than attempting the risky water landing. They ultimately concluded that Sullenberger made the right choice, the Wall Street Journal reported.

Here's the truth about three major themes of the movie:

Portrayal Of Sully

The real Sully, who has retired and now works as a consultant and speaker, appears to approve of his fictional counterpart. He posted the "Sully" trailer on his website, appeared at the movie's premiere and has been doing interviews to promote it. He even told CBC he helped set up time for Hanks and his costar Aaron Eckhart to use a flight simulator to get into character.

Like Hanks' Sully in the film, Sullenberger did suffer from PTSD. He blogged about it on his website, writing that he had insomnia, high blood pressure and flashbacks.

"The story being told came from my experiences and reflects the many challenges that I faced and successfully overcame both during and after the flight," Sullenberger said in a statement to the New York Post.

Recreation Of The Flight

Several reviews of "Sully" have pointed out that the most talked-about parts of the film will likely be the scenes from on board the flight. The plane experience itself is true-to-life. "It doesn’t just look like air travel — it feels like air travel. And if you've ever flown, you'll reach for your seat belt because you’re going to feel like you, too, are on that plane," ABC News wrote.

Rescuers who were actually on the scene for the 2009 landing were hired to help filmmakers recreate the incident, The Wrap reported. The dialogue between Hanks' Sully and his copilots is also accurate, matching cockpit recording transcripts that came out after the emergency landing, Airways Magazine reported.

The Investigation

In the film, the transportation officials are "seemingly bound and determined to prove that Sully was in error and could have made it to a nearby airport," USA Today wrote in its review.

"We're not the KGB. We're not the Gestapo," investigator Robert Benzon told the Associated Press. "We weren't out to embarrass anybody at all."

The National Transportation Safety Board told Bloomberg in a statement that it wasn't asked to be included in the production of "Sully," so "we were not afforded an opportunity to ensure our actions and words were portrayed with accurate context or reflected our perspective."