What Could Have Caused the UPS Cargo Plane Crash in Kentucky?

At least 12 people were killed and more than a dozen injured after a UPS cargo plane crashed while taking off from an airport in Louisville, Kentucky, on Tuesday night.

Aviation experts who spoke to BBC Verify believe the plane crashed after one engine failed and another appeared to be damaged during take-off.

It is unclear what caused the plane to crash, causing a huge fireball to erupt after it failed to take off from the runway. Footage showed that the fire had already engulfed one wing of the plane as it attempted to take off, which could have spread across the plane and caused the explosion, or the plane could have caught fire after colliding with an object on the ground.

The National Transportation Safety Board (NTSB), which is investigating the crash, said it recovered CCTV footage from the airport showing the plane’s left engine falling off the wing during takeoff.

The agency also recovered from the wreckage the cockpit flight recorder and the flight data recorder, known as a black box, said Todd Inman of the NTSB.

What is also evident is that the 38,000 gallons (144,000 liters) of fuel aboard the MD-11 aircraft required for the flight likely intensified the fire, which quickly spread to several buildings beyond the runway and burned for hours.

BBC Verify has been analyzing footage that emerged overnight to piece together how the crash unfolded.

UPS uses Louisville Muhammad Ali International Airport as a distribution center for its global operations and its flight 2976 was at the beginning of a 4,300-mile journey to Honolulu in Hawaii when the cargo plane attempted to take off.

Data from tracking website FlightRadar24 shows that the plane began taxiing onto runway 17R around 17:15 local time (22:15 GMT) and managed to reach a maximum speed of 214 mph (344 km/h).

But verified footage shows that by the time the plane reached this speed a fire had completely engulfed its left wing and the plane struggled to clear the runway before the explosion.

The NTSB said the plane’s engine was on fire while it was working to take off and then detached from the wing. The plane was able to climb to 175 feet and cleared a fence at the end of the runway before turning toward the buildings and businesses surrounding the airport.

Authorities issued a shelter-in-place order to local residents and sent hundreds of firefighters to the scene.

Governor Andy Beshear confirmed details seen on CCTV footage showing the plane flying just meters off the ground before a bright flash engulfed it. He is then seen crashing to the ground as a massive fireball erupts around him about a minute into his journey.

A verified clip taken by motorists on a nearby highway showed flames bursting on the horizon, while later videos showed smoke billowing from the scene.

Aerial images broadcast by local media showed debris falling onto the runway and landing on the roofs of at least two local businesses.

The air traffic control communications reviewed by BBC Verify are largely garbled and full of interference, so no meaningful conversation can be heard about the crash as it unfolded.

But analysts who spoke to BBC Verify suggested that a dramatic failure of two of the engines could have been responsible for the disaster.

The MD-11 transport aircraft uses three engines. Two are mounted under the wings and a third is integrated into the tail at the base of the vertical stabilizer.

Footage confirmed by BBC Verify showed a fire engulfing the plane’s left wing, which then pitched to the left as it attempted to gain lift and take off.

Two experts independently suggested that the left engine could have detached from the plane after suffering a mechanical or structural failure. And the NTSB later confirmed that the left engine detached from the plane’s wing during takeoff.

Separate images taken after the crash showed a charred engine on the grass next to the runway at Louisville International Airport.

Terry Tozer, a retired airline pilot and aviation safety expert, told BBC Verify it was “almost unheard of” for an engine to come loose in flight.

He referenced the American Airlines Flight 191 disaster in 1979, in which 273 people died after the plane’s engine came loose while taking off from Chicago’s O’Hare International Airport. Parts of the engine had been damaged when it was replaced on the plane, but Tozer said it was too early to say whether a similar failure caused the engine to come loose on the MD-11.

Tozer said the cargo plane would have been able to fly with just two engines, but the damage caused by the fire to the left wing was probably so extensive that it caused the plane’s engine built into the tail to lose thrust.

“With such a catastrophic event we cannot know what other damage occurred when the engine became adrift,” he said.

Marco Chan, senior lecturer in aviation operations at Buckinghamshire New University, said the images appeared to show the third engine had been damaged because it expelled a burst of smoke. The damage may have occurred while it was being pelted with debris from the fire and the engine was dislodged.

“The upper engine that ejected a cloud of smoke appears to stop almost immediately afterwards,” Chan said. “That left only the right engine producing thrust, creating a serious power imbalance and leaving the plane unable to gain altitude.

“The loss of two engines during takeoff leaves the aircraft with only a third of its power and little chance of maintaining flight, especially at maximum takeoff weight,” Chan added.

Footage after the crash showed a scene of complete chaos with multiple fires burning across a large swath of the site and smoke rising into the sky.

The plane, which was 34 years old and had been used as a passenger plane until 2006, had already completed a return trip from Louisville to Baltimore, Maryland, on Tuesday.

It has not been confirmed what cargo was aboard the Hawaii-bound flight, although authorities said the plane was not carrying anything that could create a greater risk of contamination.

“This was a long-haul cargo flight from Louisville to Honolulu, so MD-11 was carrying a large amount of jet fuel,” Chan said. “That heavy fuel load not only reduced performance but also explains the large fireball seen after the accident.”

Authorities told reporters that the plane was carrying 38,000 gallons (144,000 liters) of fuel for the long trip when it crashed. The fire was likely amplified on the ground because the plane crashed into a fuel recycling company next to the airport.

Chan said investigators will now focus on how the initial fire started and “whether debris hit the center engine and whether previous maintenance on the left engine had anything to do with it.” He added: “Weather conditions were calm and clear, so environmental factors are unlikely.”

The National Transportation Safety Board (NSTB) has sent a team to the scene and will now lead the investigation into the causes of the accident, although it may take up to two years to complete.

Additional reporting by Emma Pengelly, Kayleen Devlin and Paul Brown.