KNOXVILLE, Tenn. (WVLT) -- Federal aviation officials are trying to figure out what caused a small airplane to crash into the Tennessee River on Thursday evening.

It happened about 5:30 p.m. near Downtown Island Home Airport in South Knoxville.

Two people were on board the Cirrus SR-22 single engine aircraft when it plunged into the water.

Knoxville Fire Department officials said the pilot and passenger were both men in their forties who were returning to Knoxville following a business trip to Tampa, Florida.

The pilot apparently radioed ahead to warn that he was having mechanical issues while in the air. When he tried to land at the airstrip, the SR-22 skidded down the runway.

“They reported they were having engine problems,” said Capt. D.J. Corcoran with the Knoxville Fire Department. “Also at that time there was a downpour of rain. I don't know if that contributed to the wreck but that was also going on."

They ended up nose down in the Tennessee River, just east of the airport. Witnesses immediately called 911 and crews from the Knoxville Police Department, Knoxville Fire Department and Knox County Sheriff’s Office quickly arrived on scene. Luckily both men were able to safely escape the downed plane.

"The two men were able to get out of the aircraft fine and rescue crews picked them up from the water,” said Corcoran.

The men were uninjured and refused medical treatment once they were brought back to land.

Meanwhile the plane remained partially submerged underwater late Thursday night.

"We have oil absorbing booms that will surround the plane,” said Corcoran. “They will absorb any fuel leak coming from the plane."

The booms are just a precaution and as of late Thursday night, there was no confirmed leak.

Investigators from the Federal Aviation Administration have been dispatched to figure out what exactly happened.

The plane is registered to NXCK LLC, a corporation that lists its address on Hubbs Crossing Lane in North Knox County. Flight records indicate it was flown from Island Home to Tampa International Airport on July 26th. Prior to that, the plane was flown from Island Home Johnston County, North Carolina.

Stay with Volunteer TV News and VolunteerTV.com for the latest on this developing story.