(CNN) A plane that overran its runway and came to a stop in the St. Johns River in Jacksonville, Florida, on Friday night is still resting in the water as authorities work to investigate why it changed runways shortly before landing.

The plane was supposed to land at Naval Air Station Jacksonville to the west into the wind, as is typical for most aircraft. But the pilots requested to instead land to the east on a different runway, NTSB Vice Chairman Bruce Landsberg said Sunday.

Preliminary information from the flight data recorder shows that the plane touched down at 163 knots and then had a ground speed of 178 knots, which translates to a 15-knot tailwind.

"The pilots requested to change the active runway. We don't know what they were thinking or why they made that choice," Landsberg said. "That will be one of the things we look to find out as we go through the cockpit voice recorder."

In addition, Landsberg said there was a barrier toward the end of the runway that effectively shortened its length from 9,000 feet to 7,800 feet. Further, the maintenance log noted that the left-hand thrust reverser on the aircraft was inoperative, and there are procedures to deal with that, Landsberg said.

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