A small jet takes off at Muhammad Ali Louisville International Airport on Wednesday, November 5, as a plume of black smoke rises from a UPS jet that crashed the day before.

A UPS cargo plane bound for Honolulu, Hawaii, crashed near Louisville, Kentucky's Muhammad Ali International Airport shortly after takeoff on Tuesday, Nov. 4, killing multiple people and leaving authorities scrambling for answers about what happened.

While early photos and videos document the moments around the devastating crash, investigations into air disasters take extensive time and research. Determining the cause of the crash will be part of an already-in-progress National Transportation Safety Board investigation. Expect the full results of the inquiry to take a year or more.

The crash also comes on the heels of other high-profile aviation incidents this year, including a fatal collision between an American Airlines regional jet and an Army Black Hawk helicopter over the Potomac River in January, prompting potential safety concerns.

It also comes amid a charged political climate, with a government shutdown drawing attention to federal agencies involved in air safety, including the Federal Aviation Administration and the NTSB. Here's what to know in the early stages of the investigation:

Why did the UPS plane crash?

There's no definitive answer yet, but early photos and videos may offer clues about what went wrong.

Video footage of the crash appeared to show the plane taking off with fire on one wing, and a huge fireball erupted as it hit the ground. Several buildings in an industrial area beyond the runway were on fire after the crash, with thick black smoke rising into the sky.

Congressman Morgan McGarvey, D-Kentucky, said 28 members of the NTSB are on the ground in Louisville, aided by support staff in Washington, DC.

“They are going to analyze absolutely every bit of what happened,” he said during a press briefing on Nov. 5. “We're talking about everything that is man-made, that is machine-made, that is environmental, the NTSB is going to go over with a fine-tooth comb.”

The agency will hold its own media briefing in the afternoon.

Did the government shutdown cause the UPS plane crash?

Even in a hotly politically charged climate, politicians have generally avoided speculating about the shutdown's impact on the crash or the investigation.

"I don't know at this stage what impact (the shutdown) has, but we will be asking all questions in the hours and days ahead," McGarvey told WHAS11.

McGarvey added in Nov. 5's press briefing, however, that the shutdown would have "no impact" on the NTSB investigation. "Every resource of NTSB is being brought to bear on this," he said.

How long will the NTSB investigation take?

The NTSB has already launched an investigation. They’ll look at everything from maintenance records to flight data to weather conditions. Early findings usually come out within a few days, but the full investigation — the final report — can take 12 to 24 months. So it may be a while before we know exactly what caused this crash.

How does the UPS plane crash impact air travelers?

While cargo and passenger flights operate differently, there can be overlap: They sometimes use the same runways and air traffic control systems, and travelers may be wondering what the crash means for their upcoming flights.

In the aftermath of the crash, some passengers with upcoming flights to or from Louisville Muhammad Ali International Airport could experience disruptions. Both commercial airplanes and cargo aircraft rely on the same air traffic control towers, which also manage military and general aviation flights.

Louisville's Muhammad Ali International Airport said Runway 11/29 was open as of Wednesday morning.

"TSA screening remains on-going this morning for departing passengers," the airport said on its website. "Anyone scheduled to depart or arrive at SDF today is encouraged to closely monitor their flight status as delays and cancellations are likely following yesterday’s incident."

What has UPS said about the crash?

UPS issued a statement after the crash: "We are terribly saddened by the accident tonight in Louisville," the company said. "Our heartfelt thoughts are with everyone involved. UPS is committed to the safety of our employees, our customers, and the communities we serve. This is particularly true in Louisville, home to our airline and thousands of UPSers."

UPS said it was working with the NTSB and was in close contact with the FAA. "We will work tirelessly with state and local authorities on response efforts," according to the statement.

This story has been updated to add new information.

Contributing: James Powel, Chris Kenning, Olivia Evans, Matthew Glowicki, Amanda Lee Myers, Keisha Rowe, Stephanie Kuzydym, Thao Nguyen and Zach Wichter, USA TODAY NETWORK

This article originally appeared on USA TODAY: What caused the UPS plane crash? What we know and don't know.

Reporting by Nathan Diller and Joel Shannon, USA TODAY / USA TODAY

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