Pilots of a chartered jet that ran into a river at a Florida military base made a last-minute change to the runway where they would make a landing, a federal investigator said Sunday.

The pilots on the Miami Air International plane requested the change to air traffic controllers shortly before landing at Naval Air Station Jacksonville Friday night.

The 9,000-foot-long runway where the Boeing 737 landed was essentially limited to 7,800 feet since there was a wire barrier set up to recover Navy aircraft in instances they couldn't land on a carrier during training, said Bruce Landsberg, vice chairman of the National Transportation Safety Board.

"We don't know what they were thinking or why they made that choice," Landsberg said at a news conference. "That will be one of the things we look to find out."

Landsberg didn't elaborate on the significance of the runway change, but said it would be a focus of investigation.

NTSB investigators said they hope a cockpit voice recorder helps them answer that question, but they have been unable to recover it yet since the part of the plane where it's located is still underwater in the St. Johns River. Investigators also plan to interview the pilots, Landsberg said.

Investigators have retrieved the flight data recorder.

Landsberg said the plane recently had been in maintenance, and logs showed a left-hand thrust reverser that was inoperative.

Thrust reversers are used to divert thrust from the engine, but they typically aren't used in calculating a plane's performance, Landsberg said.

According to a Purdue University College of Engineering description , reverse thrust can be used to help an aircraft come to a stop.

"We will be looking very carefully at the maintenance of the aircraft in the several weeks prior," Landsberg said.

There were no serious injuries on the flight from a military base at Guantanamo Bay, Cuba, although almost two dozen of the 143 passengers and crew members sought medical attention for minor injuries.

Capt. Michael Connor, the base's commanding officer, said all passengers had left the base Sunday on their way to their scheduled destinations.

Some aircraft will be allowed to depart the base and be relocated so that pilots can continue with their training, but Naval Air Station Jacksonville will essentially be closed until the plane is removed from the river, Connor said.

The NTSB investigators are still deciding whether to relocate the plane off the base, which would require the use of a barge.

"How the aircraft is positioned now certainly gives you limitations on a good thorough assessment," said NTSB investigator John Lovell. "We are not aware of the extent of the damage under the waterline because it can't be seen."

All fuel needs to be removed before the plane can be moved, and that effort was complicated by the aircraft being partially submerged in the river, as well as stormy weather on Sunday, Landsberg said.

Officials said they didn't know how many gallons of fuel have spilled into the river, but engineers were using booms to contain the fuel and skimmers to vacuum up contaminants.

Divers on Sunday were sent into the plane's cargo area to search and remove a few pets that they had been unable to be rescued because of safety concerns. The investigators didn't say outright whether the animals were dead, but the pets would have been submerged for almost two days.

Cell phone video from passenger Darwing Silva captured the immediate, uncertain moments after the chartered jet landed.

A passenger shouted "Watch out! Watch out!" as other passengers and crew members cautiously walked out on a wing of the plane. Another passenger shouted, "Baby coming through!" and a man can be seen holding an infant in his arms as he walks along the other passengers in yellow life jackets getting drenched by rain.

Silva shared the video with Jacksonville television station News4Jax.

Silva told the Tampa Bay Times that passengers initially were told Friday the aircraft might not be fit for takeoff. Then the flight was cleared to leave Cuba, but with the warning there would be no air conditioning.

Even though the plane was hot, there were no other problems during the flight from Guantanamo Bay, Cuba, Silva said.

The landing at Naval Air Station Jacksonville seemed normal at first, but then the plane didn't stop on the runway. There was a loud bang, he hit his head on the ceiling, and the jet ended up in the water, Silva said.

He looked down and his ankles were in water, he said, and he heard someone yell, "Fuel!"

Silva said he helped usher people out an emergency door onto a wing.

On Sunday, Miami Air International, which operated the aircraft, notified passengers that their overhead luggage from the plane was available for pickup. The airline said passengers would be contacted directly once their checked bags were retrieved.

Also Sunday, a small, one-propeller airplane crashed into the St. Johns River in Jacksonville. The pilot, who was the only person on board and wasn't injured, was rescued by a kayaker, according to the Jacksonville Fire and Rescue Department.

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Mike Schneider reported from Orlando, Fla.