Transcript for Flight makes emergency landing because of loss of parts, violent shaking
Now to that midair scare. United airline flight making an emergency landing in Hawaii after losing an engine cover. You can see the frightening image right there looking out your passenger window to see that and David Kerley has new details and, David, the NTSB are now investigating. Reporter: They want to know what happened. It was a really shaky end of the flight to Honolulu for passenger, Michael, with part of their jet blew away and were told to base for an emergency landing. Terrifying moments when a piece of this plane an engine cover rips off in flight over the pacific ocean. Passengers recording the violent vibrations that follow. Almost felt like an explosion and a huge jolt of the plane. It had jaws started violently shaking. Reporter: The flight from San Francisco was headed to Hawaii when the part peels off. It was truly like being inside a gigantic washing machine that had all the towels moved to one side. It felt like the while plane would shake apart. Reporter: Aaron and his sisters say it wasn't just the cover coming off. Through the remainder we continued to see different pieces of debris and bolts flying out of it and hitting the side of the plane or just falling into the ocean. Reporter: The pilots were taking no chances asking for an emergency landing. We're an emergency aircraft. Roll the fire trucks. Reporter: The crew instructing passengers to brace for that landing. Brace, brace, brace. Reporter: Now the plane landed safely. Nobody was hurt. Now the engine was vibrating because of -- instead of the air smoothly going over the engine it was being bounced without that cover causing that vibration, alarming sight. Pretty scary. No incident for them. They got on the ground safely. United, guys, is going to refund all the passengers' tickets. Happy they landed safely. Scary. Thank you. Thanks, David.
This transcript has been automatically generated and may not be 100% accurate.