? Crews in the investigation of Flight 1549?s splashdown in the Hudson River are focusing on an object, located by sonar, on the bottom of the river.

Investigators say the object is about the size of the missing aircraft?s engine, but divers ran out of daylight before they could take a closer look.

The plane is being examined to better understand why the jetliner?s engines failed. Early evidence and communications from the crew lend support to the belief that the aircraft hit a flock of birds shortly after takeoff.

Police have already located pieces of debris from the plane, including flotation seat cushions, life jackets and pieces of luggage.

The pilot who safely landed the plane on the water, Chesley ?Sully? Sullenberger, attended the inauguration of President Barack Obama Tuesday. Sullenberger was personally invited by the president to spend the day with the first family.

Sullenberger was bombarded with questions by the media, but would not comment.