No fewer than nine individuals lost their lives and 11 left injured after a UPS cargo plane crashed while taking off from an international airport in Kentucky's largest city on Tuesday night.
Aircraft specialists suggest the aircraft went down after a single engine malfunctioned and another appeared to be damaged while lifting off.
It is unclear what caused the plane to crash, prompting a massive fireball to erupt after it failed to take-off from the airstrip. Footage revealed fire had already engulfed one wing of the aircraft during its takeoff attempt, potentially spreading through the plane and triggered the blast, or the jet could have caught fire upon hitting an object on the ground.
What's clear is that the 38,000 gallons of fuel aboard the MD-11 jet needed for the flight probably intensified the fire, which rapidly extended to several buildings past the airstrip and burned for hours.
How did it start?
The shipping giant uses Louisville Muhammad Ali International Airport as a logistics center for its global operations and its Flight 2976 was beginning of a 6,920 kilometer trip to Hawaii's capital when the freight aircraft attempted to take off.
Data from FlightRadar24 shows the plane started moving along the 17R runway at around 17:15 local time and attained a top speed of 214mph.
However, confirmed videos demonstrate that by the time the plane achieved this velocity a fire had completely engulfed its left wing and the aircraft failed to gain altitude before the massive explosion.
Officials activated a local safety directive to local residents and scrambled numerous fire crews to the scene.
The state's governor verified particulars seen in CCTV footage that depict the aircraft flying just metres off the ground before a intense light engulfed the plane. It is then seen slamming into the ground as a massive fire explosion erupts around it about a minute after departure.
Authenticated footage taken by drivers on adjacent roads displayed the flames erupting into the skyline while later videos revealed smoke pouring from the area.
Overhead photographs shown on regional news outlets depicted debris showering the runway and landing on the tops of at least two local businesses.
Potential causes of the accident
Air traffic control communications reviewed are largely garbled and filled with static so no clear dialogue can be discerned about the crash as it developed.
However, experts suggested that a dramatic failure of multiple engines may have been the cause of the tragedy.
The MD-11 transport plane uses three engines. Two are mounted under the airfoils, and a third is built into the tail at the bottom of the tail fin.
Footage confirmed revealed a blaze engulfing the port wing of the plane, which then tilted to the left as it tried to achieve altitude and take-off.
Multiple specialists independently suggested the left engine may have separated from the plane following a mechanical or structural failure.
Additional photographs captured post-accident displayed a burned powerplant sitting on the turf adjacent to the airstrip.
An experienced former aviator and aviation safety expert commented that it was "almost unheard of" for an powerplant to separate during operation.
He referenced the 1979 American Airlines Flight 191 disaster, in which 273 individuals were fatally injured when the plane's engine detached as it took off from O'Hare International Airport. Engine components had been compromised when it was installed on the aircraft, but the specialist stated it was premature to determine whether a similar fault led to the powerplant separation on the trijet.
The specialist said the cargo plane would have been able to fly with only two powerplants but the destruction resulting from the wing blaze was likely so great it resulted in the plane's third engine to fail to produce power.
"With such a catastrophic event we cannot determine what other damage was done when the engine came adrift," he said.
A different aircraft specialist observed the video evidence appeared to show the third engine had been damaged because it expelled a burst of smoke. The issue could have occurred while it was pelted with debris from the blaze and the engine detaching.
"The upper engine that released smoke seems to shut down right after," the specialist said. "That left only the right engine generating power, resulting in a severe power imbalance and making the plane incapable to gain height.
"Failing two powerplants while departing leaves the aircraft with only a fraction of its thrust and minimal opportunity of maintaining flight, particularly under maximum take-off weight," the expert continued.
Reasons for extensive destruction
Post-accident videos showed a situation of total disorder with numerous blazes blazing across a extensive area of the site and smoke rising upward.
The aircraft, which was three decades old and had been operated for passenger travel before conversion, had already completed one return journey from the Kentucky hub to the East Coast on the same day.
Authorities haven't verified which goods was aboard the Hawaii-bound aircraft, though officials stated the plane was not carrying anything that would pose an increased danger of environmental hazard.
"This involved extended freight transport from Kentucky to Hawaii, so the MD-11 was carrying a lot of jet fuel," a specialist said. "That heavy fuel load not only reduced performance but also accounts for the large fireball observed post-accident."
Officials informed media that the plane was carrying 38,000 gallons of fuel for the long journey when it crashed. The fire was probably intensified on the ground because the plane crashed into a fuel recycling business adjacent to the airfield.
The expert said authorities will concentrate on the origin of the blaze, and "if wreckage hit the central powerplant, and whether earlier maintenance on the portside powerplant played a role." The expert continued: "Atmospheric conditions were favorable, so weather-related causes are improbable."
The federal investigation agency has sent a team to the location and will take charge of the probe into the causes of the crash, though such inquiries may require years to complete.
