They say the safest time to travel by plane is the day after a crash, but what about when a panel is ripped from an aircraft in flight?

After part of the fuselage tore off the left side of an Alaska Airlines flight last week, authorities in the US have grounded 171 Boeing 737 MAX 9 jetliners.

The flight that sparked the safety checks was able to make an emergency landing, just minutes after take-off and all 171 passengers and six crew members were fine, bar a few reported minor injuries.

A “key missing component” from the jet was recovered in a suburban backyard by a Portland schoolteacher identified only as ‘Bob’.

National Transportation Safety Board (NTSB) chair Jennifer Homendy said she was “very relieved” it had been found.

She had earlier told reporters the aircraft part was vital to determine why the accident occurred.

“Our structures team will want to look at everything on the door — all of the components on the door to see to look at witness marks, to look at any paint transfer, what shape the door was in when found. That can tell them a lot about what occurred,” she said earlier.

The force from the loss of the plug door was strong enough to blow open the cockpit door during flight, said Homendy.

The Federal Aviation Administration (FAA) did not rule out further action as a probe began into the apparent structural failure.

Investigators will look at maintenance records, the pressurisation system and the door components.

Alaska Air said it had halted flights by 18 of its MAX 9 planes that it had resumed using on Saturday after recent in-depth inspections.

The airline said it was in discussions with the FAA “to determine what, if any, further work is required before these aircraft are returned to service”.

Source: X (Federal Aviation Administration)

It’s not the first time Boeing planes have been at the centre of safety concerns. 

In 2018, 189 people were killed on a Lion Air flight to Indonesia and five months later, 157 people on board an Ethiopian Airlines flight were killed.

Both planes were Boeing 737 MAX jets and, as a result, all were grounded globally for almost two years before eventually being cleared to fly.

Boeing fixed its control system, which mistakenly activated during both flights.

Will the Alaska Air incident affect Australian travellers?

Speaking toThe New Daily, UTS senior lecturer in tourism David Beirman said it was an “absolute miracle” that no one was sitting into the seat next to where the part of the plane broke off.

Although it wasn’t a crash and no one was seriously hurt, the sight of the exposed sky while in the air and oxygen masks coming down undoubtedly frightened those on board.

However, Beirman doesn’t think the Alaska Airlines incident will deter people from travelling by plane, simply due to the fact that aviation is incredibly safe.

“If you look at all the different modes of transport that are around, aviation is actually the safest by a long shot,” he said.

“It’s much safer than trains, which occasionally derail and have accidents. It’s certainly a lot safer than driving a car, as we all know, whenever you go out in the traffic.”

The hole where a window used to be before it blew off midair.

Although there has been quite a fuss about the Alaska Air incident, Beirman anticipates the hype to die down within a few days because the damage was structural and there were no casualties.

“An incident like this, as terrible as it was for the people who were on board that flight because it really would have spooked them, it’s going to leave a lasting impression on them,” Beirman said.

“But it will become, if I may use the term, “fish and chips wrappers” probably after about another week or so.”

Incidents just like this occur several times a year, Beirman said, while reiterating that air travel is still remarkably safe.

Alaska Air mainly flies within the US, with a few international locations in North and South America. It has grounded all Boeing 737 MAX 9 jetliners in its fleet.

Other airlines around the world have done the same, however, none of Australia’s airlines carry the specific Boeing in question.

Beirman imagines airlines will seek out planes to use in the meantime while Boeing 737 MAX 9 jetliners are grounded.

Alaska Airlines has grounded its Boeing 737 MAX 9 fleet. Photo: Getty

Why travelling by plane is so safe

Incidents in the air can happen at any time, with any aircraft.

Not only are fatalities few and far between, there’s much at stake when something goes wrong.

Beirman may not be an engineer, but he understands the industry and the very strict rules airlines have to follow.

On a global level, there’s the International Civil Aviation Organisation (ICAO), which is a UN body that sets the global minimum standards for all of the world’s aircraft.

Then there’s the International Air Transport Association (IATA), which has even stricter guidelines than the ICAO, but is voluntary. About 85 per cent of the world’s airlines are part of it.

Because of the guidelines set by the ICAO and the IATA, it isn’t a total shock that the planes have been grounded.

Alaska Airlines has issued several statements about the incident.

Below the ICAO and the IATA are the airlines. Each has a reputation to protect and any incident, even minor ones, can deter future passengers, so it is in their best interest to ensure safety is the No.1 priority.

Checking other Boeing jets also reassures stakeholders.

The aircraft maker has responded to the grounding of the planes, reiterating that safety was the company’s “top priority” and it “deeply” regrets the “impact this event has had on our customers and their passengers”.

“We agree with and fully support the FAA’s decision to require immediate inspections of 737-9 airplanes with the same configuration as the affected airplane,” Boeing said in a statement.

“In addition, a Boeing technical team is supporting the NTSB’s (National Transportation Safety Board)  investigation into last night’s event. We will remain in close contact with our regulator and customers.”

Additionally, Boeing’s president and CEO has cancelled a retreat with VPs within the company and has called for a safety meeting for all employees, according to journalist Dominic Gates.