Black box seized after 'technical' failure on Boeing-made LATAM plane

New Zealand investigators Tuesday seized the flight recorder from a Boeing-made LATAM plane, searching for the cause of a mid-air plunge that injured dozens of terrified travellers.

The Boeing 787 Dreamliner was en route from Sydney to Auckland on Monday evening when it lurched earthward without warning, slinging some unrestrained passengers out of their seats and smashing others into the cabin ceiling.

"Everyone started screaming, crying," said Australian receptionist Ellie Addison, one of 263 passengers aboard flight LA800.

"People were launched out of their seats, there was blood pouring from people's faces."

It is the latest in a string of headline-grabbing safety incidents to trouble US plane maker Boeing.

Both Boeing and Chile-based LATAM Airlines have promised to cooperate with authorities to pinpoint the cause of the unspecified "technical event".

Confusion has clouded early investigations, with both Chilean and New Zealand safety watchdogs suggesting the other nation was taking the lead.

New Zealand accident investigators said Tuesday they had started gathering evidence, "including seizing the cockpit voice and flight data recorders".

But, a spokesman added, "it is Chile's investigation".

Sales administrator Veronica Martinez said it felt like the plane had stopped mid-air, and then "we just plunged".

"People were flying, babies fell, it was horrible, lots of people were injured," she told AFP.

Emergency crews raced to Auckland Airport to meet the incoming flight, dispatching more than a dozen ambulances and other medical vehicles.

Support worker Gabriel Felipe de Oliveira Adaime said the flight was "traumatising", while fellow passenger Agustin Ramonda said it was "one of the worst three seconds of my life".

Paramedics said they treated about 50 patients. Four people remained in hospital as of Tuesday morning, Health officials told AFP.

The flight arrived on time, LATAM said in a statement.

- 'Black swan event' -

Passenger Brian Jokat said he spoke to one of the pilots after the plane touched down.

"I asked him 'what happened?' and he said to me 'I lost my instrumentation briefly and then it just came back all of a sudden'," he told national broadcaster Radio New Zealand.

Air accident safety investigator Joe Hattley told AFP that technical problems were rare in modern aircraft.

"That flight record will be key to understanding this event," said Hattley, who also teaches at the University of New South Wales in Australia.

"It will tell investigators if it was an atmospheric event or a technical problem with the aircraft."

Ashok Poduval, a commercial airline pilot for 15 years and now chief executive of the Massey University School of Aviation, said the incident appeared to be an ultra-rare "black swan event".

"A malfunction of the autopilot or unexpected clear-air turbulence are some of the possibilities that could cause an upset of this nature," he said.

Data from airline tracker FlightAware showed the plane began losing altitude about two hours into the three-hour flight. But it was unclear if this was part of its descent into Auckland.

- Safety issues -

US manufacturer Boeing said it "stands ready to support the investigation-related activities as requested."

The aircraft maker has suffered a series of safety issues in recent years, including the fatal Lion Air and Ethiopian Airlines crashes of 737 MAX planes in 2018 and 2019 that killed more than 350 people.

The manufacturer is still reeling from a near-catastrophic incident in January when a fuselage panel on a Boeing 737 MAX 9 Alaska Airlines jet blew off mid-flight in the United States.

Last week, a Boeing 777 jetliner bound for Japan had to make an emergency landing shortly after takeoff from San Francisco when a wheel fell off and plunged into an airport parking lot, damaging several cars.

US regulators earlier this month gave Boeing 90 days to come up with a plan addressing quality control issues, with the Federal Aviation Administration chief saying the company must "commit to real and profound improvements".

Boeing's share price has dropped 25 percent since the start of the year.

Upstream Aviation consultant Tim Collins said Boeing has had some production issues, "but generally most aircraft are good and reliable."

He said Boeing made up about 50 percent of the global jet fleet.

"While some people might think twice about Boeing's reputation, the same would happen if an Airbus crashed tomorrow."