The Way this Louisville Cargo Aircraft Crash Unfolded and What Could Have Caused It

No fewer than nine people have died and 11 left injured after a freight aircraft crashed while taking off from a major air hub in Kentucky's largest city on Tuesday night.

Aviation experts suggest the plane crashed due to one engine failed and a second seemed compromised while lifting off.

The exact cause remains unknown what caused the plane to crash, leading to a huge explosion to erupt after it couldn't become airborne from the airstrip. Video evidence showed flames were consuming one wing of the plane while it was attempting to take off, 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 144,000 litres of fuel aboard the trijet aircraft needed for the flight likely escalated the fire, which rapidly extended to several buildings past the airstrip and burned for hours.

What initiated the incident?

UPS operates from Louisville Muhammad Ali International Airport as a logistics center for its worldwide network and its designated flight was at the start of a 4,300 mile journey to Honolulu in Hawaii when the freight aircraft initiated departure.

Data from flight monitoring services indicates the plane began to taxi along the 17R runway at around 17:15 local time and managed to reach a top speed of 344km/h.

But verified footage shows that when 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 shelter-in-place order to local residents and dispatched hundreds of firefighters to the location.

The state's governor verified particulars visible in security camera recordings that depict the aircraft flying just feet above the surface before a bright flash engulfed the plane. It is then seen slamming into the ground as a massive fire explosion erupts around it about a minute into its journey.

Authenticated footage recorded by drivers on adjacent roads displayed the flames erupting into the skyline while subsequent recordings showed smoke billowing from the scene.

Overhead photographs shown on local media showed debris showering the runway and falling onto the roofs of at least two local businesses.

Potential causes of the accident

ATC transmissions examined are largely garbled and filled with static so no meaningful conversation can be heard about the crash as it developed.

However, experts suggested that a dramatic failure of two of the engines may have been responsible for the tragedy.

The MD-11 transport plane employs three engines. Two are mounted under the wings, and a third is built into the tail at the bottom of the tail fin.

Footage confirmed revealed a blaze engulfing the left wing of the aircraft, which then tilted to the left as it attempted to gain lift and take-off.

Multiple specialists independently suggested the left engine may have separated from the plane following a mechanical or structural failure.

Separate images taken after the crash displayed a charred engine sitting on the grass next to the runway.

An experienced former aviator and aviation safety expert commented that it was "extremely rare" for an powerplant to separate during operation.

He referenced the 1979 aviation disaster disaster, in which 273 people were killed after 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 caused the powerplant separation on the MD-11.

The specialist explained the freight aircraft would have been able to fly with just two engines but the damage resulting from the fire on the left wing was likely so great it resulted in the aircraft's remaining engine to fail to produce power.

"With such a catastrophic event we cannot determine what other damage was done when the engine came adrift," the expert commented.

Another aviation expert said the footage seemed to indicate the remaining powerplant had been compromised because it released smoke. The damage could have occurred while it was struck by wreckage from the fire and the powerplant separation.

"The upper engine that released smoke appears to wind down almost immediately afterwards," the specialist stated. "This left just the right engine producing thrust, resulting in a severe power imbalance and making the plane incapable to gain height.

"Losing two engines during take-off results in only a third of its power and minimal opportunity of maintaining flight, particularly under full departure mass," the specialist added.

Reasons for extensive destruction

Post-accident videos revealed a situation of total disorder with multiple fires blazing across a extensive area of the site and smoke rising upward.

The plane, which was three decades old and had been used as a passenger plane before conversion, had previously made one round trip from Louisville to Baltimore in Maryland on Tuesday.

It has not been confirmed which goods was aboard the flight bound for Hawaii, though authorities said the aircraft didn't contain anything that would pose an increased danger of contamination.

"This was a long-haul cargo flight from Louisville to Honolulu, so the trijet was carrying a significant fuel quantity," a specialist said. "The substantial fuel quantity not only diminished capability but also accounts for the large fireball seen after the crash."

Officials told reporters that the plane was transporting 144,000 litres of fuel for the extended trip when it crashed. The fire was probably intensified on the surface because the aircraft slammed into a fuel processing facility next to the airport.

The expert indicated authorities will concentrate on the origin of the blaze, and "whether debris struck the central powerplant, and if previous repairs on the portside powerplant were a factor." The expert continued: "Atmospheric conditions were favorable, so weather-related causes are unlikely."

The National Transportation Safety Board has dispatched personnel to the location and will take charge of the investigation into the accident's origins, though such inquiries may require years to complete.