Lidle, 34, and a flight instructor, 27-year-old Tyler Stanger, died on Oct. 11, 2006, when Lidle's Cirrus SR-20 plane collided with a high-rise apartment building on Manhattan's Upper East Side.
The NTSB report stated that it has not been able to determine who was piloting the plane at the time of the accident. An investigation revealed no system, structural or engine malfunctions.
"The accident is a great tragedy in which a pleasure flight went horribly wrong and ultimately cost the lives of two young men," NTSB chairman Mark Rosenker said. "The pilots placed themselves in a precarious situation that could have been prevented by better judgment and planning."
Following the Yankees' playoff elimination in the American League Division Series, Lidle had said that he planned to fly his plane across the country to his California home, stopping periodically along the way to refuel.
Lidle and Stanger -- a commercial pilot with a flight instructor's certificate -- took off from New Jersey's Teterboro Airport on Oct. 11 in what was believed to have been a brief sightseeing excursion. The plane was piloted around the Statue of Liberty and up New York's East River, in view of Yankee Stadium.
Using radar data, the report concluded that the plane's pilot had attempted a 180-degree turn maneuver inside a limited turning space, but did not aggressively bank the airplane throughout the turn.
The pilot also did not use the full available width of the river. Wind may have played a factor, the report said.
As a result of the crash, the Federal Aviation Administration ordered small fixed-wing planes not to fly over the East River unless the pilot was in contact with air traffic controllers -- a regulation that the NTSB indicated will become permanent.
The NTSB said that Lidle's plane did not have a cockpit voice recorder or a flight data recorder, which may have yielded further information.
The identity of the person piloting the plane is of vital importance to Lidle's widow, Melanie, who has filed a suit against the insurance company MetLife, Inc., claiming that she is owed $1 million under Major League Baseball's benefit plan.
The plan contains an exclusion for an aircraft incident in which Lidle would have been acting in any role other than as a passenger, The Associated Press reported.
Melanie Lidle and the pitcher's 6-year-old son, Christopher, were invited to Yankee Stadium to throw out a ceremonial first pitch on April 2 as part of a moving Opening Day ceremony.
Jason Giambi, a high school and professional teammate of Lidle's, assisted with the ceremony and later drove in three runs in a game he dedicated to Lidle's memory.
"That was probably one of the toughest things I've ever had to do in my life," Giambi said then.
Lidle was acquired by the Yankees last July 30 as part of a multiple-player trade with the Philadelphia Phillies that also netted outfielder Bobby Abreu. He appeared in 10 games for the Yankees, going 4-3 with a 5.16 ERA in nine starts, plus one more appearance in the postseason.
The Yankees announced this spring that they would honor Lidle's memory by wearing a black stripe on the left sleeve of their home and road uniforms for the entire 2007 season. Lidle's locker stall at Yankee Stadium will also be left unused in tribute.
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.