An aviation expert has explained the crucial question investigators need to answer next after a UPS cargo plane crashed during take-off on Tuesday (November 4).
At least 13 people have died after a triple-engined McDonnell Douglas MD-11 went down moments after taking off from Louisville Muhammad Ali International Airport, Kentucky.
Six people are still missing after the crash.
Three crew members were onboard the airliner, which departed at 5.13pm, beginning what was meant to be an eight-and-a-half-hour flight to Honolulu, Hawaii.
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According to tracking data from FlightRadar24, Flight 2976 taxied along runway 17R and accelerated to around 214 mph during takeoff.
Moments later, footage captured the left wing bursting into flames as the plane climbed to roughly 175 feet, clearing the airport’s perimeter fence.
Investigators from the National Transport Safety Board (NTSB) believe that the engine detached from the left wing shortly afterwards, causing the aircraft to veer sideways and crash into several structures on the ground, including a fuel recycling facility, an auto repair business and a water bottling plant.
As the NTSB continue their investigation, a former pilot has broken down the questions that remain.
Shawn Pruchnicki, assistant professor at The Ohio State University in the College of Engineering, flew as a Captain with a Delta Connection carrier for 10 years.
He told UNILAD that losing an engine alone is not necessarily enough to cause a plane to crash.
"That, in and of itself, doesn’t cause an airplane to crash. In fact, airliners are designed so that if you have an engine fire that you’re unable to put out, you go through the procedure, but if you can’t extinguish it and it keeps burning, sometimes the engine can even burn itself right off the airplane wing and fall off," Pruchnicki explained.
"Of course, it’s a big deal, but it doesn’t mean you’re going to crash."
The big question that remains, Pruchnicki says, is exactly why the plane crashed when its engine fell off.
"The concern we’re thinking about now as investigators is whether it damaged vital components on that wing that were required for the airplane to continue to fly," he continued.
One component is the flaps which hang down off the back of the wing, while the other is the slats, located on the front of the wing.
"Did it damage those, or cause them to automatically retract?" Pruchnicki asked.
He went on to compare the situation to a similar tragedy that took place back in 1979, also in the US.
Some 273 people were killed when American Airlines Flight 191 smashed into the ground at Chicago's O'Hare International Airport, again, after one of the plane's engines fell off during takeoff.
Noting there was 'no fire' in that incident, Pruchnicki added: "The engine broke off, came up over the wing, hit the slat, and damaged it so badly that, because the hydraulic system failed, the slats on the left side retracted.
"The pilot flew the failed-engine procedure beautifully, but because the slats retracted on that side, the wing was now below stall speed, so the left wing stalled and the airplane rolled over to the left and crashed."
This leaves experts questioning what happened during the Louisville crash and whether it played out in a similar way.
Referencing shocking video footage of the November 4 crash from a truck driver circulating online, Pruchnicki said: "That one clearly shows the airplane rolling to the west before it impacts the ground.
"It’s almost, not quite 90 degrees, but getting pretty close.
"I saw that video, I thought, 'Oh man, is this another 191?' So I’m talking to all my investigator buddies that I know, and we’re all thinking the same thing."
"Now, we’re not saying that because we know that’s what it is - we’re just saying, wow, that looks similar," he clarified, before adding: "I’m sure that’s what the NTSB is focused on - why did that wing stall? It’s pretty clear that the wing stalled, and that’s why the airplane rolled over to the left."
Ellie Kemp