WINDSOR LOCKS, Conn. (CBS/AP) -- A World War II-era B-17 bomber with 13 people aboard crashed and burned at the Hartford airport after encountering mechanical trouble on takeoff Wednesday, killing seven of them.
The four-engine, propeller-driven plane struggled to get into the air and slammed into a maintenance building at Bradley International Airport as the pilots circled back for a landing, officials and witnesses said.
It had 10 passengers and three crew members, authorities said.
"There are fatalities," said James Rovella, the commissioner of Connecticut's Department of Emergency Services, at an airport press conference Wednesday afternoon. He said some of those on board suffered severe burns and "the victims are very difficult to identify."
Some of the survivors of the crash were critically injured, authorities said. One person on the ground was also hurt in the crash and a firefighter involved in the response suffered a minor injury. No children were on the plane.
Related: Former B-17 Pilot Speaks Out
The death toll of seven could rise, Rovella said. He said some lives were likely saved by the efforts of people including a person who raced to help the victims and people on the plane who helped others to escape the fire by opening a hatch, Rovella said.
The FAA said the vintage Boeing B-17 bomber crashed while trying to land on a runway at about 10 a.m. The plane was operated by the Collings Foundation, an educational organization based in Stow, Massachusetts.
The flight crew notified air traffic controllers "that there was an issue with the aircraft" about five minutes into the flight, Connecticut Airport Authority Executive Director Kevin Dillon said.
"The aircraft obviously lost control," Dillon said.
The National Transportation Safety Board sent a team of 10 to investigate the cause of the crash.
"We know that the crew circled back to runway six and attempted to land on runway six," said Jennifer Homendy of the NTSB. "We don't have more information on what that issue was at this time to share."
The NTSB will provide a preliminary report in 7-10 days and asked the public to send any photos or videos that may help in the investigation to witness@NTSB.gov.
Photos on social media showed thick black smoke from the crash above the airport.
Witnesses said it appeared the plane lost one of its four engines.
"A big plume of smoke came out the back. You could hear it sputtering and he wasn't climbing anymore," Brian Hamer told WFSB-TV. "He was making a very large, very wide turn to make it back to the airport."
Bill Schweitzer spotted the plane near his house. He also thought one of the B-17's engines was stalled.
"I see it coming in, flying low right over the horizon, right at me and I'm like, 'oh my goodness.' And then I start hearing the pop, pop, pop, pop," Schweitzer told WBZ-TV. "The one engine is running out of time with the other engines."
Antonio Arreguin said he had parked at a construction site near the airport for breakfast when he heard an explosion. He said he did not see the plane but could feel the heat from the fire, which was about 250 yards away.
"In front of me, I see this big ball of orange fire, and I knew something happened," he said. "The ball of fire was very big."
A smaller explosion followed about a minute after the first blast, he said. He saw emergency crews scrambling within seconds.
The airport reopened one of its runways at about 2 p.m.; travelers are being told to check with their airline about their flight status.
The Collings Foundation focuses on automobile and aviation history. Its "Wings Of Freedom" Tour, offering flights on vintage bomber planes to the public, came to Bradley Airport on Monday and was scheduled to last through Thursday.
"Our thoughts and prayers are with those who were on that flight and we will be forever grateful to the heroic efforts of the first responders at Bradley," the foundation said in a statement. "The Collings Foundation flight team is fully cooperating with officials to determine the cause of the crash of the B-17 Flying Fortress and will comment further when details become known."
Only a handful of the roaring, four-engine Boeing B-17s are still airworthy. They were critical in breaking Nazi Germany's industrial war machine during World War II.
The Collings Foundation said that the same plane in Wednesday's crash also crashed in August 1987 air show near Pittsburgh, injuring several people. The bomber overshot a runway while attempting to land and plunged down a hillside as spectators waited for the show's finale.
The foundation said that the plane was hit by a severe crosswind after it touched down and that the right wing lifted into the air, causing it to overshoot the runway. The plane was damaged but later restored.
WBZ-TV's Bill Shields reports
The B-17 was built in 1945, too late for combat in World War II, according to the foundation.
It served in a rescue squadron and a military air transport service before being subjected to the effects of three nuclear explosions during testing, the foundation said. After a 13-year "cooling off" period, the plane was sold as scrap and eventually was restored. The foundation bought it 1986.
"This is kind of shocking; it's a loss to lose a B-17," said Hamer, whose father served in the Air Force. "I mean, there aren't very many of those left."
Immediate family members looking for information on the plane crash can call 860-685-8190.
(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)
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